As far as I am aware most approaches revolve around the doping of the part
which emits light. Normally more than one led is used each giving off a
fairly narrow range of colour, and then combining them to make a
perceptually white light.
I have also seen some that refine this a bit with internal filtering, but
essentially, as far as I am aware, nobody has made a single led element that
has a sufficiently wide band output to give white on its own.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"James Wilkinson Sword" wrote in message
news
Yes, I've googled it, but there are many different approaches. Which one
is used in domestic LED bulbs?

Yes that is true, but once again its because the bandwidth of an led is
quite narrow.
I feel this thread is a bit of a slight troll here as I think this very
topic was discussed here not very many months ago, as regards lighting that
could be set to different tints.
Brian

--
----- -
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please!
"Graham." wrote in message
...
On Tue, 25 Apr 2017 12:25:35 +0100, "James Wilkinson Sword"
wrote:

Yes, I've googled it, but there are many different approaches. Which one
is used in domestic LED bulbs?

Ultra-violet LED exciting a white phosphor, much the same principle
used in florescents.

--

Graham.
%Profound_observation%

And of course I read every thread.


On Wed, 26 Apr 2017 08:58:47 +0100, Brian Gaff wrote:

Yes that is true, but once again its because the bandwidth of an led is
quite narrow.
I feel this thread is a bit of a slight troll here as I think this very
topic was discussed here not very many months ago, as regards lighting that
could be set to different tints.
Brian



--
You keep believing, I'll keep evolving

With a few junctions and a few phosphors, I can't see why we can't make a real sun spectrum. All we have is cool white and warm white.


On Wed, 26 Apr 2017 08:56:46 +0100, Brian Gaff wrote:

As far as I am aware most approaches revolve around the doping of the part
which emits light. Normally more than one led is used each giving off a
fairly narrow range of colour, and then combining them to make a
perceptually white light.
I have also seen some that refine this a bit with internal filtering, but
essentially, as far as I am aware, nobody has made a single led element that
has a sufficiently wide band output to give white on its own.
Brian



--
You keep believing, I'll keep evolving

James Wilkinson Sword wrote

With a few junctions and a few phosphors, I can't see why we can't make a
real sun spectrum.

Because the sun produces a quite uniform spectrum
because of the way it emits the light.

All we have is cool white and warm white.

Wrong, as always.


On Wed, 26 Apr 2017 08:56:46 +0100, Brian Gaff
wrote:

As far as I am aware most approaches revolve around the doping of the
part
which emits light. Normally more than one led is used each giving off a
fairly narrow range of colour, and then combining them to make a
perceptually white light.
I have also seen some that refine this a bit with internal filtering,
but
essentially, as far as I am aware, nobody has made a single led element
that
has a sufficiently wide band output to give white on its own.
Brian



--
You keep believing, I'll keep evolving

"James Wilkinson Sword" wrote in message
news
As far as I am aware most approaches revolve around the doping of the
part
which emits light. Normally more than one led is used each giving off a
fairly narrow range of colour, and then combining them to make a
perceptually white light.
I have also seen some that refine this a bit with internal filtering,
but
essentially, as far as I am aware, nobody has made a single led element
that
has a sufficiently wide band output to give white on its own.

We've just got a couple of Philips Hue bulbs which can be set to a variety
of different colours (as well as being dimmable), presumably by varying the
proportions of different coloured LEDs. It was my wife's idea and they are a
bit of a gimmick. I tend to use the one in my study mainly on fairly neutral
white (ranging between warm white and daylight) but my wife likes to set
hers to lurid purple or red as background lighting when she reads on her
Kindle (which produces its own light, so the colour of the room lighting
doesn't affect the colour of the text). We got them partly to test the
technology, controlling by mobile phone app or Alexa voice recognition; if
we were to get any more we'd go for much cheaper fixed-colour ones.

What is interesting is that even the whitest light, which appears slightly
blue to the eye, shows on a digital camera as being a little warmer than
full sunlight (about 5000K). A "daylight" CFL alongside it (OK, I was
curious so I did a comparison!) looks slightly warmer by eye but the camera
sees it as being cooler than the LED.

This goes to show that the eye is a very poor indicator of colour
temperature, and that it has a lot of auto-adjustment built into the
eye/brain mechanism.

Of course, if the digital camera is set to auto-white-balance rather than a
preset "tungsten", "fluorescent", "sunlight", "shade", it adjusts too.

Some time I'll have to try some test photos using the same Hue bulb on
various colours and brightnesses, and see what the colour rendition of real
subjects is like in various conditions.

When I've done it in the past, using sunlight, shade, tungsten bulb, warm
white fluorescent tube, daylight CFL and daylight LED GU10, the camera's
auto-white has made them all look fairly similar in terms of overall colour
cast, but red objects tend to be a bit darker and less vibrant with CFL and
LED.

I dread to think what the spectrum of some of these bulbs is like, but I bet
there are a lot of holes in the spectrum compared with a black-body radiator
like a tungsten bulb or the sun (ignoring very small gaps in sunlight due to
absorbtion lines of the atmosphere). I dimmed a tungsten bulb from full
brightness to barely lit, using a conventional thyristor dimmer, and the
camera's auto-white and auto-exposure made all the test photos look pretty
well identical, which is how it *ought* to be with LEDs and CFLs.

I presume LEDs vary their brightness by varying the duty cycle of a square
wave (and maybe even varying its frequency too). I've always wondered why
this doesn't causing any banding or beating when those lights are used as
studio lights in a TV studio.

In article ,
NY wrote:
What is interesting is that even the whitest light, which appears
slightly blue to the eye, shows on a digital camera as being a little
warmer than full sunlight (about 5000K). A "daylight" CFL alongside it
(OK, I was curious so I did a comparison!) looks slightly warmer by eye
but the camera sees it as being cooler than the LED.

This goes to show that the eye is a very poor indicator of colour
temperature, and that it has a lot of auto-adjustment built into the
eye/brain mechanism.

Colour temperature to the eye is subjective. The real problem with many of
this sort of light source is they ain't continuous or smooth over the
visible light spectrum. Which can make colours - like paint - appear a
different colour (or shade) than in daylight, or halogen.

This may not matter much in a domestic living setting, but certainly can
in a workshop, etc. Or even a kitchen.

--
*Why do we say something is out of whack? What is a whack?

Dave Plowman London SW
To e-mail, change noise into sound.

"Dave Plowman (News)" wrote in message
...
In article ,
NY wrote:
What is interesting is that even the whitest light, which appears
slightly blue to the eye, shows on a digital camera as being a little
warmer than full sunlight (about 5000K). A "daylight" CFL alongside it
(OK, I was curious so I did a comparison!) looks slightly warmer by eye
but the camera sees it as being cooler than the LED.

This goes to show that the eye is a very poor indicator of colour
temperature, and that it has a lot of auto-adjustment built into the
eye/brain mechanism.

Colour temperature to the eye is subjective. The real problem with many of
this sort of light source is they ain't continuous or smooth over the
visible light spectrum. Which can make colours - like paint - appear a
different colour (or shade) than in daylight, or halogen.

This may not matter much in a domestic living setting, but certainly can
in a workshop, etc. Or even a kitchen.

Or if you are viewing certain precious stones which change colour
dramatically under sunlight or tungsten or one of the many CFL or LED
lights.

The other thing you have to be careful of is pulsed lights with very short
persistence. I first learned this from my grandpa who had a lathe for making
model engineering models. He had his garage workshop illuminated with
fluorescent strip lights but he had a tungsten bulb that he could shine on
the work. He showed me how important that light was by running the lathe a
certain speeds which were an exact multiple of the mains frequency. Under
the fluorescents along, the work appeared to be stationary (and therefore
safe to touch); under the tungsten light you could see enough blur to make
it obvious that it was spinning and therefore dangerous to touch. And he was
catering for that moment of inattention; normally when you have your brain
devoted to the task, it's blindingly obvious that if you can hear the motor,
the chuck is spinning.

I gather that in situations where pulsed light (eg fluorescent or LED) is
used as the only light in engineering works, they have circuitry which
throws in occasional "extra random heartbeats" into the mains-fed lights,
which is enough to give some blur or jitter on the work in the lathe to make
it clear that it is spinning, even though dead-regular mains at 50 Hz would
freeze it stroboscopically. I heard of this when someone was filming a video
in an engineering works and got all sorts of flicker even though the camera
was set to a flicker-free 50 Hz refresh. He had to get H&S to sanction
temporarily disabling this safety feature during filming because it was
noticeable even though most of the light came from the filming lights.


My wife has an LED desktop lamp with LEDs that are supposed to give better
colour matching more like daylight or tungsten (ie with fewer peaks and
troughs). But it does have an annoying side-effect. I don't know what
frequency they pulse the LEDs at, but occasionally if you move your eyes
rapidly from one thing to another you can see a trail of sharp images,
especially if it's dimmed so there's probably more space and less mark in
each cycle of the lights. It's like you see with some car tail lights. or
with the "red/green man" signs on the pole of pedestrian lights - the large
bright lights that you see from the opposite side of the crossing are fine,
but the little telltale light on the pole beside the button has bad flicker
that is visible out of the corner of your eye.

On Wed, 26 Apr 2017 11:06:24 +0100, Rod Speed wrote:

James Wilkinson Sword wrote

With a few junctions and a few phosphors, I can't see why we can't make a
real sun spectrum.

Because the sun produces a quite uniform spectrum
because of the way it emits the light.

So? Put several LEDs in the package, then add phosphors to smooth things over. I'm not asking for identical, just something vaguely similar.

All we have is cool white and warm white.

Wrong, as always.

Apart from some specialised ones perhaps. But most LED bulbs only have two whites.


On Wed, 26 Apr 2017 08:56:46 +0100, Brian Gaff
wrote:

As far as I am aware most approaches revolve around the doping of the
part
which emits light. Normally more than one led is used each giving off a
fairly narrow range of colour, and then combining them to make a
perceptually white light.
I have also seen some that refine this a bit with internal filtering,
but
essentially, as far as I am aware, nobody has made a single led element
that
has a sufficiently wide band output to give white on its own.
Brian


--
How do they seperate the men from the boys in the Navy?
With a crowbar.

On Wed, 26 Apr 2017 01:57:25 +0100, Johnny B Good wrote:

On Tue, 25 Apr 2017 21:12:37 +0000, Johnny B Good wrote:

====snip====

I thought a quick follow up with some references would be in order.

It's been a rather disappointing wait for Cree to begin fulfilling that
(probably ill advised) promise made by their spokesperson just over
three years ago when they announced their record breaking achievement in
LED efficacy. Here we are, some 50 percent further along than their
upper timescale to get 300Lm/W lamps to market, with lamps of only half
that efficacy to show for their efforts thus far.

If you google for "303Lm/W LED Cree" you'll be swamped by Cree's own web
page hits where they seem to be trying to re-write history. However, I
did manage to find an original trade press report:

https://www.forbes.com/sites/peterde...will-get-even-
more-efficient-cree-passes-300-lumens-per-watt/#374ac9112611

Apologies for the line wrap.

Interestingly, the 'spokesperson' turned out to be no less a personage
than Cree's vice president for product strategy, Mike Watson himself who
was quoted as saying,

"While some of these performance improvements already impact our current
developments, commercializing products with this level of performance
typically takes between 18 to 24 months from when we announce a research
and development result."


Still, at least *some* progress has finally materialised at long last,
so I suppose we ought to be grateful to finally be free of the 2013
'Time Warp' we seem to have been living in for the past 3 or 4 years.
:-) Better late than never.


Having re-read that article, it is only now, with the benefit of
hindsight, that I recognise the skilful use of Marketing Weasel Speak by
Cree's VP for Product Strategy.

I'm guessing the hope was that their one and only competitor, Philips
Lighting, would give up trying to win the race and drop out of the game
(as they subsequently did), allowing Cree to just coast along and milk
this promise of improved LED lamps for as long as the (technically
ignorant) consumer masses would tolerate the tiny incremental
improvements being drip fed into the market place.

With Philips Lighting gone, it's no wonder we seem to have been "Stuck
in 2013" for the past four years as far as LED lighting products are
concerned. I suppose we should eventually see 250 LPW lamps make an
appearance since Cree will have no choice but to spend that margin
between their best achieved 303LPW laboratory example and the current
marketing period's "Best LPW offering to date".

Before anyone else jumps in with a best guess at when we're likely to
see 250LPW LED GLS lamps finally make an appearance, I'll offer mine.

I reckon Cree could get away with a 20LPW improvement per marketing
season which, given the size of the worldwide market they have exclusive
access to, is likely to straddle a two year interval. Assuming the
current LPW is now at the 150 mark, I reckon this gives Cree another
decade's worth of high living before they're finally obliged to offer a
250LPW lamp sometime towards the end of the third decade of this current
millenium (assuming Trump hasn't plunged the whole world into Nuclear
Armageddon during the next 4 or 8 years of his presidency[1]).

[1] In which case, I can foresee Cree diversifying into tallow and wick
based lighting technology, always, of course, assuming enough of their
board of directors survive "The Event" to keep the operation going as a
vital part of the business of rebuilding a post apocalyptic society (and
thereby get their snouts back into the trough).

Why do you hate CREE so much? They appear to be the ones at the forefront of LED technology.

--
7 wheelchair athletes have been banned from the Paralympics after they tested positive for WD40.

NY wrote
James Wilkinson Sword wrote

As far as I am aware most approaches revolve around the doping of the
part which emits light. Normally more than one led is used each giving
off a fairly narrow range of colour, and then combining them to make a
perceptually white light.

I have also seen some that refine this a bit with internal filtering,
but essentially, as far as I am aware, nobody has made a single led
element that has a sufficiently wide band output to give white on its
own.

We've just got a couple of Philips Hue bulbs which can be set to a variety
of different colours (as well as being dimmable), presumably by varying
the proportions of different coloured LEDs.

I'm in the process of changing over to Hues entirely.

It was my wife's idea and they are a bit of a gimmick. I tend to use the
one in my study mainly on fairly neutral white (ranging between warm white
and daylight)

I prefer the cool white end myself. Surprised me a bit because
I used to use PAR38 floods inside the house because I preferred
the light from those to the long tube fluoros with daylight tubes.

but my wife likes to set hers to lurid purple or red as background
lighting when she reads on her Kindle (which produces its own light, so
the colour of the room lighting doesn't affect the colour of the text).

Urk don't do that at all myself.

We got them partly to test the technology, controlling by mobile phone app
or Alexa voice recognition;

I did it mainly to move to complete automation of the lights
and other stuff like the electric blanket etc. Ideally I would
prefer to operate without having to ever use light switches
at all and have the system work out when someone is in a
particular location and decide if light is required there etc.

Not totally automatable probably unless I can work out some
time based rules too, because I prefer to have full light when
I am actually eating, but not when using the computer or
watching video and that's all done in the one place.

Not yet clear if time rules added to presence detection
will work. It might because I do eat at a very fixed time
for the evening meal and don't need full light for my
very minimal breakfast which is just a huge great slab
of toast, as thick as will still fit in the toaster.

if we were to get any more we'd go for much cheaper fixed-colour ones.

I did start with that starter kit but hate the very orangy color of those.

Don't mind so much in the bedroom, but hated it for the main
armchair I do most stuff from, including eating the evening meal.

Didn't like it in the kitchen either so I got some of the fully color temp
controllable ones to replace those. The fixed color temp ones will be
fine in the less often used places like the room full of brewed beer and
distilled spirits etc in massive great piles of our milk crates with the
beer mostly in full sized beer bottles we call long necks.

What is interesting is that even the whitest light, which appears slightly
blue to the eye,

Doesn't to me for some reason. With the Light strip Plus that I have
two of now in the kitchen, I can't find the white that just has the big
white leds on, the other two colored leds are on at a low level too.

I've only been driving them with the apps so far tho, not by programming.

shows on a digital camera as being a little warmer than full sunlight
(about 5000K). A "daylight" CFL alongside it (OK, I was curious so I did a
comparison!) looks slightly warmer by eye but the camera sees it as being
cooler than the LED.

This goes to show that the eye is a very poor indicator of colour
temperature, and that it has a lot of auto-
adjustment built into the eye/brain mechanism.

Of course, if the digital camera is set to auto-white-balance rather than
a preset "tungsten", "fluorescent", "sunlight", "shade", it adjusts too.

Some time I'll have to try some test photos using the same Hue bulb on
various colours and brightnesses, and see what the colour rendition of
real subjects is like in various conditions.

When I want to put stuff on one of the facebook buy sell swap
groups or ebay etc I normally just put on a table outside in the sun.

Would be more convenient to have a dedicated
table inside with a Hue or two I spose.

When I've done it in the past, using sunlight, shade, tungsten bulb, warm
white fluorescent tube, daylight CFL and daylight LED GU10, the camera's
auto-white has made them all look fairly similar in terms of overall
colour cast, but red objects tend to be a bit darker and less vibrant with
CFL and LED.

I dread to think what the spectrum of some of these bulbs is like,

Yeah, bet its really weird.

but I bet there are a lot of holes in the spectrum compared with a
black-body radiator like a tungsten bulb or the sun (ignoring very small
gaps in sunlight due to absorbtion lines of the atmosphere). I dimmed a
tungsten bulb from full brightness to barely lit, using a conventional
thyristor dimmer, and the camera's auto-white and auto-exposure made all
the test photos look pretty well identical, which is how it *ought* to be
with LEDs and CFLs.

I presume LEDs vary their brightness by varying the duty cycle of a square
wave

IMO its much more likely to be done by varying the
constant current but I don't know that for a fact. It
would be easy to check with the Lightstrip Plus using
a CRO, must dig mine out and see what they do.

(and maybe even varying its frequency too).

Dunno what the point of varying the frequency would be.

I've always wondered why this doesn't causing any banding or beating when
those lights are used as studio lights in a TV studio.

Yeah, that's the other reason for varying the current and not doing PWM
with those, That inevitably going to be a major problem with photographing
stuff, even for domestic situations rather than professional with digital
cameras.

James Wilkinson Sword wrote
Rod Speed wrote
James Wilkinson Sword wrote

With a few junctions and a few phosphors, I can't see why we can't make
a real sun spectrum.

Because the sun produces a quite uniform spectrum because of the way it
emits the light.

So?

So you'll never get even close with leds.

Put several LEDs in the package,

All that does if put more spikes in the spectrum.

then add phosphors to smooth things over.

Phosphors don't do that. They have their own spikes.

I'm not asking for identical, just something vaguely similar.

It isnt even vaguely similar spectrum wise.

Adequate for a domestic situation, but that's all.

All we have is cool white and warm white.

Wrong, as always.

Apart from some specialised ones perhaps.

Nothing specialised about the ones where you can
control the color temp because they can do 16M colors.

But most LED bulbs only have two whites.

Most can in fact do full RGB.

On Wed, 26 Apr 2017 08:56:46 +0100, Brian Gaff

wrote:

As far as I am aware most approaches revolve around the doping of the
part
which emits light. Normally more than one led is used each giving off a
fairly narrow range of colour, and then combining them to make a
perceptually white light.
I have also seen some that refine this a bit with internal filtering,
but
essentially, as far as I am aware, nobody has made a single led element
that
has a sufficiently wide band output to give white on its own.
Brian

On 2017-04-26, Dave Plowman (News) wrote:

In article ,
NY wrote:
What is interesting is that even the whitest light, which appears
slightly blue to the eye, shows on a digital camera as being a little
warmer than full sunlight (about 5000K). A "daylight" CFL alongside it
(OK, I was curious so I did a comparison!) looks slightly warmer by eye
but the camera sees it as being cooler than the LED.

This goes to show that the eye is a very poor indicator of colour
temperature, and that it has a lot of auto-adjustment built into the
eye/brain mechanism.

Colour temperature to the eye is subjective. The real problem with many of
this sort of light source is they ain't continuous or smooth over the
visible light spectrum. Which can make colours - like paint - appear a
different colour (or shade) than in daylight, or halogen.

This may not matter much in a domestic living setting, but certainly can
in a workshop, etc. Or even a kitchen.

I saw an interesting science demonstration once where the presenter
had a box painted white on the inside, with three lights of different
colours (RBG, I think) shining into it. He turned down the house
lights & adjusted the brightness of each one until the audience
generally agreed that the inside of the box looked white. Then he put
various fruits & vegetables in the box & they did not look right.

On 27/04/2017 12:15, Adam Funk wrote:
On 2017-04-26, Dave Plowman (News) wrote:

In article ,
NY wrote:
What is interesting is that even the whitest light, which appears
slightly blue to the eye, shows on a digital camera as being a little
warmer than full sunlight (about 5000K). A "daylight" CFL alongside it
(OK, I was curious so I did a comparison!) looks slightly warmer by eye
but the camera sees it as being cooler than the LED.

This goes to show that the eye is a very poor indicator of colour
temperature, and that it has a lot of auto-adjustment built into the
eye/brain mechanism.

Colour temperature to the eye is subjective. The real problem with many of
this sort of light source is they ain't continuous or smooth over the
visible light spectrum. Which can make colours - like paint - appear a
different colour (or shade) than in daylight, or halogen.

This may not matter much in a domestic living setting, but certainly can
in a workshop, etc. Or even a kitchen.

I saw an interesting science demonstration once where the presenter
had a box painted white on the inside, with three lights of different
colours (RBG, I think) shining into it. He turned down the house
lights & adjusted the brightness of each one until the audience
generally agreed that the inside of the box looked white. Then he put
various fruits & vegetables in the box & they did not look right.


Thats because the eye doesn't see a continuous range of colour.
It only sees the relative levels of colours in three fairly wide bands
and the brain constructs the colours from that information.

Its quite easy to fool the brain about the actual colour and what you
think you see.
There are images where you can move a square of material from one spot
to another and its perceived colour changes.
Add in that the sun is not a black body emitter of light and has some
very strong yellow lines in it and you can see why colour varies so much
from person to person.

On 2017-04-27, dennis home wrote:

On 27/04/2017 12:15, Adam Funk wrote:
On 2017-04-26, Dave Plowman (News) wrote:

Colour temperature to the eye is subjective. The real problem with many of
this sort of light source is they ain't continuous or smooth over the
visible light spectrum. Which can make colours - like paint - appear a
different colour (or shade) than in daylight, or halogen.

This may not matter much in a domestic living setting, but certainly can
in a workshop, etc. Or even a kitchen.

I saw an interesting science demonstration once where the presenter
had a box painted white on the inside, with three lights of different
colours (RBG, I think) shining into it. He turned down the house
lights & adjusted the brightness of each one until the audience
generally agreed that the inside of the box looked white. Then he put
various fruits & vegetables in the box & they did not look right.


Thats because the eye doesn't see a continuous range of colour.
It only sees the relative levels of colours in three fairly wide bands
and the brain constructs the colours from that information.

Its quite easy to fool the brain about the actual colour and what you
think you see.
There are images where you can move a square of material from one spot
to another and its perceived colour changes.
Add in that the sun is not a black body emitter of light and has some
very strong yellow lines in it and you can see why colour varies so much
from person to person.

AIUI, photographs & RGB displays meant for humans won't fool insects
because they pick up 5 (or is it 6?) colour bands.

On 27/04/2017 16:42, Adam Funk wrote:
AIUI, photographs & RGB displays meant for humans won't fool insects
because they pick up 5 (or is it 6?) colour bands.

I think it varies.

Goldfish have 4.

A Mantis shrimp has a full on spectrometer, and a polarimeter.

Andy

On Wed, 26 Apr 2017 11:46:15 +0100, NY wrote:

"James Wilkinson Sword" wrote in message
news
As far as I am aware most approaches revolve around the doping of the
part
which emits light. Normally more than one led is used each giving off a
fairly narrow range of colour, and then combining them to make a
perceptually white light.
I have also seen some that refine this a bit with internal filtering,
but
essentially, as far as I am aware, nobody has made a single led element
that
has a sufficiently wide band output to give white on its own.

We've just got a couple of Philips Hue bulbs which can be set to a variety
of different colours (as well as being dimmable), presumably by varying the
proportions of different coloured LEDs. It was my wife's idea and they are a
bit of a gimmick. I tend to use the one in my study mainly on fairly neutral
white (ranging between warm white and daylight) but my wife likes to set
hers to lurid purple or red as background lighting when she reads on her
Kindle (which produces its own light, so the colour of the room lighting
doesn't affect the colour of the text). We got them partly to test the
technology, controlling by mobile phone app or Alexa voice recognition; if
we were to get any more we'd go for much cheaper fixed-colour ones.

What is interesting is that even the whitest light, which appears slightly
blue to the eye, shows on a digital camera as being a little warmer than
full sunlight (about 5000K). A "daylight" CFL alongside it (OK, I was
curious so I did a comparison!) looks slightly warmer by eye but the camera
sees it as being cooler than the LED.

This goes to show that the eye is a very poor indicator of colour
temperature, and that it has a lot of auto-adjustment built into the
eye/brain mechanism.

Of course, if the digital camera is set to auto-white-balance rather than a
preset "tungsten", "fluorescent", "sunlight", "shade", it adjusts too.

Some time I'll have to try some test photos using the same Hue bulb on
various colours and brightnesses, and see what the colour rendition of real
subjects is like in various conditions.

What about turning off the camera's white balance, taking a photo, and seeing what it shows up like in Photoshop?

When I've done it in the past, using sunlight, shade, tungsten bulb, warm
white fluorescent tube, daylight CFL and daylight LED GU10, the camera's
auto-white has made them all look fairly similar in terms of overall colour
cast, but red objects tend to be a bit darker and less vibrant with CFL and
LED.

I dread to think what the spectrum of some of these bulbs is like, but I bet
there are a lot of holes in the spectrum compared with a black-body radiator
like a tungsten bulb or the sun (ignoring very small gaps in sunlight due to
absorbtion lines of the atmosphere). I dimmed a tungsten bulb from full
brightness to barely lit, using a conventional thyristor dimmer, and the
camera's auto-white and auto-exposure made all the test photos look pretty
well identical, which is how it *ought* to be with LEDs and CFLs.

I presume LEDs vary their brightness by varying the duty cycle of a square
wave (and maybe even varying its frequency too). I've always wondered why
this doesn't causing any banding or beating when those lights are used as
studio lights in a TV studio.

Only cheap **** LEDs. Ones made well are not pulsed.

--
I am sorry I offended you - I should have lied.

On Wed, 26 Apr 2017 20:26:12 +0100, Rod Speed wrote:

NY wrote
James Wilkinson Sword wrote

As far as I am aware most approaches revolve around the doping of the
part which emits light. Normally more than one led is used each giving
off a fairly narrow range of colour, and then combining them to make a
perceptually white light.

I have also seen some that refine this a bit with internal filtering,
but essentially, as far as I am aware, nobody has made a single led
element that has a sufficiently wide band output to give white on its
own.

We've just got a couple of Philips Hue bulbs which can be set to a variety
of different colours (as well as being dimmable), presumably by varying
the proportions of different coloured LEDs.

I'm in the process of changing over to Hues entirely.

It was my wife's idea and they are a bit of a gimmick. I tend to use the
one in my study mainly on fairly neutral white (ranging between warm white
and daylight)

I prefer the cool white end myself. Surprised me a bit because
I used to use PAR38 floods inside the house because I preferred
the light from those to the long tube fluoros with daylight tubes.

but my wife likes to set hers to lurid purple or red as background
lighting when she reads on her Kindle (which produces its own light, so
the colour of the room lighting doesn't affect the colour of the text).

Urk don't do that at all myself.

We got them partly to test the technology, controlling by mobile phone app
or Alexa voice recognition;

I did it mainly to move to complete automation of the lights
and other stuff like the electric blanket etc. Ideally I would
prefer to operate without having to ever use light switches
at all and have the system work out when someone is in a
particular location and decide if light is required there etc.

Not totally automatable probably unless I can work out some
time based rules too, because I prefer to have full light when
I am actually eating, but not when using the computer or
watching video and that's all done in the one place.

All my lights simply operate by motion sensor and light sensor. With different time limits for each room. Eg the bedroom is shorter so it goes off shortly after I get into bed. The living room is longer to allow for me sitting still while watching TV.

I don't have the problem you do with wanting different brightnesses for different tasks, I just like it bright all the time unless I'm sleeping.

Not yet clear if time rules added to presence detection
will work. It might because I do eat at a very fixed time
for the evening meal and don't need full light for my
very minimal breakfast which is just a huge great slab
of toast, as thick as will still fit in the toaster.

if we were to get any more we'd go for much cheaper fixed-colour ones.

I did start with that starter kit but hate the very orangy color of those.

Don't mind so much in the bedroom, but hated it for the main
armchair I do most stuff from, including eating the evening meal.

Didn't like it in the kitchen either so I got some of the fully color temp
controllable ones to replace those. The fixed color temp ones will be
fine in the less often used places like the room full of brewed beer and
distilled spirits etc in massive great piles of our milk crates with the
beer mostly in full sized beer bottles we call long necks.

I just use daylight white everywhere. Sunlight is the nicest, so the closest to that is preferred.

What is interesting is that even the whitest light, which appears slightly
blue to the eye,

Doesn't to me for some reason.

Does to me if I've been looking at warm lights recently. But the headlight bulbs in BMWs always look blue, probably because they are. They should be outlawed. Too much like an emergency vehicle.

With the Light strip Plus that I have
two of now in the kitchen, I can't find the white that just has the big
white leds on, the other two colored leds are on at a low level too.

I've only been driving them with the apps so far tho, not by programming.

shows on a digital camera as being a little warmer than full sunlight
(about 5000K). A "daylight" CFL alongside it (OK, I was curious so I did a
comparison!) looks slightly warmer by eye but the camera sees it as being
cooler than the LED.

This goes to show that the eye is a very poor indicator of colour
temperature, and that it has a lot of auto-
adjustment built into the eye/brain mechanism.

Of course, if the digital camera is set to auto-white-balance rather than
a preset "tungsten", "fluorescent", "sunlight", "shade", it adjusts too.

Some time I'll have to try some test photos using the same Hue bulb on
various colours and brightnesses, and see what the colour rendition of
real subjects is like in various conditions.

When I want to put stuff on one of the facebook buy sell swap
groups or ebay etc I normally just put on a table outside in the sun.

Can't do that in the UK, you'd have to wait a few weeks.

Would be more convenient to have a dedicated
table inside with a Hue or two I spose.

When I've done it in the past, using sunlight, shade, tungsten bulb, warm
white fluorescent tube, daylight CFL and daylight LED GU10, the camera's
auto-white has made them all look fairly similar in terms of overall
colour cast, but red objects tend to be a bit darker and less vibrant with
CFL and LED.

I dread to think what the spectrum of some of these bulbs is like,

Yeah, bet its really weird.

but I bet there are a lot of holes in the spectrum compared with a
black-body radiator like a tungsten bulb or the sun (ignoring very small
gaps in sunlight due to absorbtion lines of the atmosphere). I dimmed a
tungsten bulb from full brightness to barely lit, using a conventional
thyristor dimmer, and the camera's auto-white and auto-exposure made all
the test photos look pretty well identical, which is how it *ought* to be
with LEDs and CFLs.

I presume LEDs vary their brightness by varying the duty cycle of a square
wave

IMO its much more likely to be done by varying the
constant current but I don't know that for a fact. It
would be easy to check with the Lightstrip Plus using
a CRO, must dig mine out and see what they do.

(and maybe even varying its frequency too).

Dunno what the point of varying the frequency would be.

Same pulse width more often to make it brighter?

I've always wondered why this doesn't causing any banding or beating when
those lights are used as studio lights in a TV studio.

Yeah, that's the other reason for varying the current and not doing PWM
with those, That inevitably going to be a major problem with photographing
stuff, even for domestic situations rather than professional with digital
cameras.

Car lights look damn stupid when being filmed (and some annoy me when I'm driving about as I can se the flicker). You'd think the more expensive cars would use proper LEDs without flashing.

--
The best parliament is a well-hung one?

On Wed, 26 Apr 2017 13:45:18 +0100, NY wrote:

"Dave Plowman (News)" wrote in message
...
In article ,
NY wrote:
What is interesting is that even the whitest light, which appears
slightly blue to the eye, shows on a digital camera as being a little
warmer than full sunlight (about 5000K). A "daylight" CFL alongside it
(OK, I was curious so I did a comparison!) looks slightly warmer by eye
but the camera sees it as being cooler than the LED.

This goes to show that the eye is a very poor indicator of colour
temperature, and that it has a lot of auto-adjustment built into the
eye/brain mechanism.

Colour temperature to the eye is subjective. The real problem with many of
this sort of light source is they ain't continuous or smooth over the
visible light spectrum. Which can make colours - like paint - appear a
different colour (or shade) than in daylight, or halogen.

This may not matter much in a domestic living setting, but certainly can
in a workshop, etc. Or even a kitchen.

Or if you are viewing certain precious stones which change colour
dramatically under sunlight or tungsten or one of the many CFL or LED
lights.

The other thing you have to be careful of is pulsed lights with very short
persistence. I first learned this from my grandpa who had a lathe for making
model engineering models. He had his garage workshop illuminated with
fluorescent strip lights but he had a tungsten bulb that he could shine on
the work. He showed me how important that light was by running the lathe a
certain speeds which were an exact multiple of the mains frequency. Under
the fluorescents along, the work appeared to be stationary (and therefore
safe to touch); under the tungsten light you could see enough blur to make
it obvious that it was spinning and therefore dangerous to touch. And he was
catering for that moment of inattention; normally when you have your brain
devoted to the task, it's blindingly obvious that if you can hear the motor,
the chuck is spinning.

I gather that in situations where pulsed light (eg fluorescent or LED) is
used as the only light in engineering works, they have circuitry which
throws in occasional "extra random heartbeats" into the mains-fed lights,
which is enough to give some blur or jitter on the work in the lathe to make
it clear that it is spinning, even though dead-regular mains at 50 Hz would
freeze it stroboscopically. I heard of this when someone was filming a video
in an engineering works and got all sorts of flicker even though the camera
was set to a flicker-free 50 Hz refresh. He had to get H&S to sanction
temporarily disabling this safety feature during filming because it was
noticeable even though most of the light came from the filming lights.


My wife has an LED desktop lamp with LEDs that are supposed to give better
colour matching more like daylight or tungsten (ie with fewer peaks and
troughs). But it does have an annoying side-effect. I don't know what
frequency they pulse the LEDs at, but occasionally if you move your eyes
rapidly from one thing to another you can see a trail of sharp images,
especially if it's dimmed so there's probably more space and less mark in
each cycle of the lights. It's like you see with some car tail lights. or
with the "red/green man" signs on the pole of pedestrian lights - the large
bright lights that you see from the opposite side of the crossing are fine,
but the little telltale light on the pole beside the button has bad flicker
that is visible out of the corner of your eye.

A decent LED light doesn't pulse.

--
If you are having sex with TWO women and ONE more woman walks in, what do you have?
Divorce proceedings, most likely.

"James Wilkinson Sword" wrote in message
news
On Wed, 26 Apr 2017 20:26:12 +0100, Rod Speed
wrote:

NY wrote
James Wilkinson Sword wrote

As far as I am aware most approaches revolve around the doping of the
part which emits light. Normally more than one led is used each giving
off a fairly narrow range of colour, and then combining them to make a
perceptually white light.

I have also seen some that refine this a bit with internal filtering,
but essentially, as far as I am aware, nobody has made a single led
element that has a sufficiently wide band output to give white on its
own.

We've just got a couple of Philips Hue bulbs which can be set to a
variety
of different colours (as well as being dimmable), presumably by varying
the proportions of different coloured LEDs.

I'm in the process of changing over to Hues entirely.

It was my wife's idea and they are a bit of a gimmick. I tend to use the
one in my study mainly on fairly neutral white (ranging between warm
white
and daylight)

I prefer the cool white end myself. Surprised me a bit because
I used to use PAR38 floods inside the house because I preferred
the light from those to the long tube fluoros with daylight tubes.

but my wife likes to set hers to lurid purple or red as background
lighting when she reads on her Kindle (which produces its own light, so
the colour of the room lighting doesn't affect the colour of the text).

Urk don't do that at all myself.

We got them partly to test the technology, controlling by mobile phone
app
or Alexa voice recognition;

I did it mainly to move to complete automation of the lights
and other stuff like the electric blanket etc. Ideally I would
prefer to operate without having to ever use light switches
at all and have the system work out when someone is in a
particular location and decide if light is required there etc.

Not totally automatable probably unless I can work out some
time based rules too, because I prefer to have full light when
I am actually eating, but not when using the computer or
watching video and that's all done in the one place.

All my lights simply operate by motion sensor and light sensor

I prefer different light levels for different situations.

With different time limits for each room. Eg the bedroom is shorter so it
goes off shortly after I get into bed. The living room is longer to allow
for me sitting still while watching TV.

Trouble is that the time isnt just determined by the location.

I don't have the problem you do with wanting different brightnesses for
different tasks, I just like it bright all the time unless I'm sleeping.

I prefer it much brighter when I am say dismantling
and fixing something than when watching TV etc.

And I want a much more complicated sequence in some situations.

Ideally the system should be able to work out when you
have just got up for a **** in the night and when you are
getting up to start the day, still before the sun gets up,
so it has the light level appropriate for using the scales,
which is different to just having a ****.

And be able to get up without any lights on at all in the
middle of the might if you hear something suspicious
and want to check on what is going on etc.

Ideally it should learn stuff too instead of having to be programmed.

Not yet clear if time rules added to presence detection
will work. It might because I do eat at a very fixed time
for the evening meal and don't need full light for my
very minimal breakfast which is just a huge great slab
of toast, as thick as will still fit in the toaster.

if we were to get any more we'd go for much cheaper fixed-colour ones.

I did start with that starter kit but hate the very orangy color of
those.

Don't mind so much in the bedroom, but hated it for the main
armchair I do most stuff from, including eating the evening meal.

Didn't like it in the kitchen either so I got some of the fully color
temp
controllable ones to replace those. The fixed color temp ones will be
fine in the less often used places like the room full of brewed beer and
distilled spirits etc in massive great piles of our milk crates with the
beer mostly in full sized beer bottles we call long necks.

I just use daylight white everywhere. Sunlight is the nicest, so the
closest to that is preferred.

I prefer more variation than that.

What is interesting is that even the whitest light, which appears
slightly blue to the eye,

Doesn't to me for some reason.

Does to me if I've been looking at warm lights recently. But the
headlight bulbs in BMWs always look blue, probably because they are. They
should be outlawed. Too much like an emergency vehicle.

Our emergency vehicles always have both red and blue
so they stand out like dogs balls and no cars ever look
anything like them. Those lights are much higher too,
at roof level and flashing too.

With the Light strip Plus that I have
two of now in the kitchen, I can't find the white that just has the big
white leds on, the other two colored leds are on at a low level too.

I've only been driving them with the apps so far tho, not by programming.

shows on a digital camera as being a little warmer than full sunlight
(about 5000K). A "daylight" CFL alongside it (OK, I was curious so I did
a
comparison!) looks slightly warmer by eye but the camera sees it as
being
cooler than the LED.

This goes to show that the eye is a very poor indicator of colour
temperature, and that it has a lot of auto-
adjustment built into the eye/brain mechanism.

Of course, if the digital camera is set to auto-white-balance rather
than
a preset "tungsten", "fluorescent", "sunlight", "shade", it adjusts too.

Some time I'll have to try some test photos using the same Hue bulb on
various colours and brightnesses, and see what the colour rendition of
real subjects is like in various conditions.

When I want to put stuff on one of the facebook buy sell swap
groups or ebay etc I normally just put on a table outside in the sun.

Can't do that in the UK, you'd have to wait a few weeks.

Yep, not surprising those of you lot with a clue migrate.

Would be more convenient to have a dedicated
table inside with a Hue or two I spose.

When I've done it in the past, using sunlight, shade, tungsten bulb,
warm
white fluorescent tube, daylight CFL and daylight LED GU10, the camera's
auto-white has made them all look fairly similar in terms of overall
colour cast, but red objects tend to be a bit darker and less vibrant
with
CFL and LED.

I dread to think what the spectrum of some of these bulbs is like,

Yeah, bet its really weird.

but I bet there are a lot of holes in the spectrum compared with a
black-body radiator like a tungsten bulb or the sun (ignoring very small
gaps in sunlight due to absorbtion lines of the atmosphere). I dimmed a
tungsten bulb from full brightness to barely lit, using a conventional
thyristor dimmer, and the camera's auto-white and auto-exposure made all
the test photos look pretty well identical, which is how it *ought* to
be
with LEDs and CFLs.

I presume LEDs vary their brightness by varying the duty cycle of a
square
wave

IMO its much more likely to be done by varying the
constant current but I don't know that for a fact. It
would be easy to check with the Lightstrip Plus using
a CRO, must dig mine out and see what they do.

(and maybe even varying its frequency too).

Dunno what the point of varying the frequency would be.

Same pulse width more often to make it brighter?

That's the duty cycle, not the frequency.

I've always wondered why this doesn't causing any banding or beating
when
those lights are used as studio lights in a TV studio.

Yeah, that's the other reason for varying the current and not doing PWM
with those, That inevitably going to be a major problem with
photographing
stuff, even for domestic situations rather than professional with digital
cameras.

Car lights look damn stupid when being filmed (and some annoy me when I'm
driving about as I can se the flicker). You'd think the more expensive
cars would use proper LEDs without flashing.

Not economically feasible with lights that bright.

The Peeler wrote:
Follow Birdbrain's and Rot Speed's idiotic endless threads and you'll
understand! BG




Sop you have found another target for your inane constant postings ?

On Tue, 25 Apr 2017 23:38:31 +0100, Rod Speed wrote:



"James Wilkinson Sword" wrote in message
news
On Tue, 25 Apr 2017 23:07:38 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 22:08:34 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 21:01:37 +0100, Rod Speed

wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 19:34:38 +0100, Rod Speed

wrote:

James Wilkinson Sword wrote
Graham. wrote
James Wilkinson Sword wrote

Yes, I've googled it, but there are many different approaches.
Which one is used in domestic LED bulbs?

Ultra-violet LED exciting a white phosphor,
much the same principle used in florescents.

That's what I would have assumed, but when you
look at a switched off white LED, it's not white.

All that means is that it isnt white when it doesn't have UV
falling
on it and that the protective outer isnt the phosphor itself.

I would have expected it to have a white coating that
can be seen like on a switched off fluorescent tube.

The difference is that leds don't have glass as the protective
outer.

Those adjustable-by-remote ones you have, just how many colours can
you
make?

They claim 16M

Do they only have R G and B emitters,

Nope. The strips where the leds are visible have one big led and a
couple
of smaller RGB ones. Not clear why there is more than one RGB one,
presumably because they arent anything like as bright as the white
one.

Just discovered I can't actually take a photo of the strip with the
leds
lit in the dark it completely ****s the exposure system in the phone.

Use a real camera

Don't have one anymore and wouldn't have any film for it even if I did.

I meant a real digital camera, with proper options like manual control
of
focussing and aperture for situations like this.

Don't bother with those, stupid waste of money given that the
phone does almost all I ever need and is with me all the time.

It's a child's toy compared to a proper camera.

Couldn't care less. It does what I want to do almost all of
the time and the times when it doesn't as so few that its not
worth having something more capable for those situation.

There likely is an app that allows full manual control
of the exposure but I havent bothered to look because
its not worth my time to even look for one.

Only any good to take a photo to show someone something, prove something
happened etc.

Its good for a hell of a lot more than that, like being a handy
video recorder that's with me all the time, handy for taking a
photo of shelf price stickers instead of recording prices any
other way, handy for taking photos of ID plates, handy for
taking photos of stuff that I would otherwise have to lie
flat on my face on the ground to see, handy for stuff with
print on it so fine and such poor contrast that I cant even
read, etc etc etc.

I can't say I need a camera at random like that. Only if I'm going out somewhere and want to take pictures, so I just take a proper camera. I see no reason to ever carry a phone with me, my mobile actually stays at home almost all the time. I occasionally take it with me if I know I need to phone someone on the way, otherwise I prefer not to have it get lost, broken, wet, stolen, etc.

The quality is awful.

Even sillier than you usually manage.

Well for gullible fools like you that spend hundreds on an Iphone it might be good quality. I just pay 10 quid for one. It texts, it calls, and it'll take a good enough picture if I have to, say for evidence of a car crash.

Simply not room on a phone for a proper lens.

Don't need a proper lens, I don't take that sort of photo.

A phone is not a camera, it's a handy thing which can take a dodgy photo
at a push.

Nothing dodgy about any of the ones I have taken.

Show me an example of a quality photo from your phone.

I don't bother with that sort of photo. There are plenty online.

And show me something like an animal in the distance you've zoomed in on.

Don't take that sort of photo.

Take a picture of a galah in a tree etc.

No galahs in my trees currently.

Have a look on Youtube of the truly awful quality videos people take with their phones.

--
Is God willing to prevent evil, but not able? Then he is not omnipotent.
Is he able, but not willing? Then he is malevolent.
Is he both able and willing? Then whence cometh evil?
Is he neither able nor willing? Then why call him God?
- Epicurus (341- 270 BC)

"James Wilkinson Sword" wrote in message
news
On Tue, 25 Apr 2017 23:38:31 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news
On Tue, 25 Apr 2017 23:07:38 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 22:08:34 +0100, Rod Speed

wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 21:01:37 +0100, Rod Speed

wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 19:34:38 +0100, Rod Speed

wrote:

James Wilkinson Sword wrote
Graham. wrote
James Wilkinson Sword wrote

Yes, I've googled it, but there are many different approaches.
Which one is used in domestic LED bulbs?

Ultra-violet LED exciting a white phosphor,
much the same principle used in florescents.

That's what I would have assumed, but when you
look at a switched off white LED, it's not white.

All that means is that it isnt white when it doesn't have UV
falling
on it and that the protective outer isnt the phosphor itself.

I would have expected it to have a white coating that
can be seen like on a switched off fluorescent tube.

The difference is that leds don't have glass as the protective
outer.

Those adjustable-by-remote ones you have, just how many colours
can
you
make?

They claim 16M

Do they only have R G and B emitters,

Nope. The strips where the leds are visible have one big led and a
couple
of smaller RGB ones. Not clear why there is more than one RGB one,
presumably because they arent anything like as bright as the white
one.

Just discovered I can't actually take a photo of the strip with the
leds
lit in the dark it completely ****s the exposure system in the
phone.

Use a real camera

Don't have one anymore and wouldn't have any film for it even if I
did.

I meant a real digital camera, with proper options like manual control
of
focussing and aperture for situations like this.

Don't bother with those, stupid waste of money given that the
phone does almost all I ever need and is with me all the time.

It's a child's toy compared to a proper camera.

Couldn't care less. It does what I want to do almost all of
the time and the times when it doesn't as so few that its not
worth having something more capable for those situation.

There likely is an app that allows full manual control
of the exposure but I havent bothered to look because
its not worth my time to even look for one.

Only any good to take a photo to show someone something, prove something
happened etc.

Its good for a hell of a lot more than that, like being a handy
video recorder that's with me all the time, handy for taking a
photo of shelf price stickers instead of recording prices any
other way, handy for taking photos of ID plates, handy for
taking photos of stuff that I would otherwise have to lie
flat on my face on the ground to see, handy for stuff with
print on it so fine and such poor contrast that I cant even
read, etc etc etc.

I can't say I need a camera at random like that.

Only because you are too stupid to think of using it for that.

Only if I'm going out somewhere and want to take pictures, so I just take
a proper camera.

You cant always predict when you will want to take
a picture, most obviously when some fool runs into
your car and you need to take a picture of the eejut
in case he later claims he wasn't there etc.

I see no reason to ever carry a phone with me,

Yes, you are that terminal a ****wit.

my mobile actually stays at home almost all the time.

Yes, you are that terminal a ****wit.

I occasionally take it with me if I know I need to phone someone on the
way,

But you cant always anticipate when you will need to do that.

otherwise I prefer not to have it get lost, broken, wet, stolen, etc.

I've never ever had that happen to any of mine.

The quality is awful.

Even sillier than you usually manage.

Well for gullible fools like you that spend hundreds on an Iphone it might
be good quality.

Much better quality than this **** below.

I just pay 10 quid for one. It texts, it calls, and it'll take a good
enough picture if I have to, say for evidence of a car crash.

Not when you have left it at home it wont.

Simply not room on a phone for a proper lens.

Don't need a proper lens, I don't take that sort of photo.

A phone is not a camera, it's a handy thing which can take a dodgy
photo
at a push.

Nothing dodgy about any of the ones I have taken.

Show me an example of a quality photo from your phone.

I don't bother with that sort of photo. There are plenty online.

And show me something like an animal in the distance you've zoomed in
on.

Don't take that sort of photo.

Take a picture of a galah in a tree etc.

No galahs in my trees currently.

Have a look on Youtube of the truly awful quality videos people take with
their phones.

Irrelevant to what the best of them are like.

On Wed, 26 Apr 2017 01:04:04 +0100, Rod Speed wrote:



"James Wilkinson Sword" wrote in message
news
On Tue, 25 Apr 2017 23:56:44 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 23:04:08 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 22:12:37 +0100, Johnny B Good
wrote:

On Tue, 25 Apr 2017 14:27:29 +0100, Martin Brown wrote:

On 25/04/2017 13:27, Graham. wrote:
On Tue, 25 Apr 2017 12:25:35 +0100, "James Wilkinson Sword"
wrote:

Yes, I've googled it, but there are many different approaches..
Which
one is used in domestic LED bulbs?

Ultra-violet LED exciting a white phosphor, much the same principle
used in florescents.

It is usually a high efficiency blue LED pump exciting a yellow
phosphor
with that mix determining the nominal colour temperature. It is
quite
peaky in the blue and more of a wide hump around the yellow. The
phosphor usually looks yellow and sits on top of the LED.

http://i.stack.imgur.com/lkyXG.png

The visible light flux out of an LED die on a high efficiency LED
these
days is about the same order of magnitude as the sun's photosphere.

It is a lot more obvious on the devices which use a remote phosphor.

http://www.cree.com/led-components/m...e-Phosphor.pdf

An interesting read (note the use of the expression "loosing
efficiency"
on page 8 regarding Fig 7a). Also of note is the copyright date of
this
document which is the year of their record breaking 303Lm/W led
efficacy
achievement in February/March of that year when the Cree Spokesperson
let
slip to the trade press that such laboratory achievements typically
took
a further 18 to 24 months of development before making their début on
store shelves for public consumption.

A simple arithmetic calculation reveals that this scheduled
development
has slipped by a rather conservatively estimated 13 months. :-( The
best
Lm/W efficacy figures I've noted recently have been around the 125 to
145
Lm/W mark. The former being a 1500Lm 12W GLS B22 2700K Warm White
lamp
I
sampled from a Home Bargains store for the princely sum of £2.99
which
turned out to have an *actual* consumption figure of 14 watts.

I thought the best LEDs were equivalent to 10W out per 1W in. Eg a
10W
LED bulb should be equivalent to a 100W incandescent. A 100W
incandescent
is 1435 lumens. So your bulb is consuming 14W to give out about 105W.
Not as good as I thought.

Since its illumination power doesn't seem as impressively bright as
I
was expecting (even making allowances for the eye's logarithmic
response
to brightness), I rather doubt the additional 2 watts is hiking the
claimed 1500Lm to 1750Lms as one might expect if the additional 2
watts
was simply the result of overly wide tolerances in the 'electronic
ballast circuit' causing the LEDs to be overdriven to a higher than
designed Lumens output.

I have a sneaking suspicion that the claims of "1500 Lumens at 12W
(100W
eqv)" have been based on the best of a sampling of these lamps off
the
production line, possibly based on the maximum positive tolerance
limit
of the 'nominal' power consumption to boot for good measure (+10%? =
13.2W) so might more typically be nearer the 110Lm/W mark than to the
claimed 125Lm/W figure. Even the claimed efficacy is not a
particularly
massive improvement over the 81Lm/W efficacy figures typical of many
LED
GLS lamps of just over three years ago.

Companies lie, they always do. Cameras state x MP, and if you take a
photo at full resolution, it's ****. Hard disks don't use gigabytes,
but
billions of bytes, shaving off a little.

The 145Lm/W lamps I saw were the grossly overpriced 1600Lm LES 11W
examples being offered by Asda. I might have considered buying one if
they'd been more sanely priced but at something like 10 to 18 quid a
pop
(I didn't bother trying to pin the confusing shelf price labelling
down
any tighter than that - it was enough to know that it was at least 3
times pricier than I'd been prepared to pay in Home and Bargain), I
wasn't in the least bit tempted.

I'm currently using this sort of thing:
http://www.ebay.co.uk/itm/231644564446

I want complete remote control of on/off, color temp and dimming, by
voice.

I don't see the need for that.

I do, I don't want the same light level all the time that its useful to
have
the light on.

I prefer a brighter light on what I am eating than when I am typing after
eating and a different light level when watching recorded videos etc.

Odd, I just like it bright all the time so I can see what I'm doing.

I do want to do that when eating or repairing stuff,
but not when using the computer or watching videos.

Why not?

I make the TV/monitor bright enough to see in that amount of ambient
light. The exception is my bedroom where I have a dimmer light so I don't
wake up and get dazzled.

Yeah, tho I prefer a soft start there, but want full
brightness so I can read the non backlit scales better.

I should get some automatically recording scales
but currently havent found any that are even that
reproducible so they read the same thing if you
weigh yourself say 5 times in a row. Had a hell
of a job finding a decent set of digital scales
that don't have any recording capability at all.

I don't have scales in the bedroom, don't they normally live in the bathroom?

Anyway why are you so obsessed with your weight?

All my rooms have one or more PIR/daylight sensors. They come on if
it's dark and someone (or a pet) is moving in the room. I never
manually turn on a light.

Too crude. I don't want the same light level all the time when its dark.

Don't when I get up either. I prefer to light to fade up over a
second or so it isnt too bright initially but is full brightness a
bit later when I weigh myself so I can see the scale properly.

Bedroom dim, every other room bright. Simpler that way.

Not viable when you want full brightness for reading the scales.

Your eyes must really suck.

And much more convenient physically too. The Hue Lightstrip Plus starts
with a 2M strip and has 1M plug in extensions with up to 8 allowed and
they go in the standard led strip extrusions that are much less bulky
than
yours and you can get in single lengths up to 10m or more in length so
you can have the one thing covering the entire long axis of even the
longest room and with joiners to go for 100m in total if you need to.

Mine are very easy. You plug in one strip to the power. Then they all
join to that one. As for physical mounting, ONE single screw in a
little clip supports each strip.

Useless for me because the only sensible place to attach
anything is to the base flange of the galvanised steel beams
that form the entire roof/ceiling structure at ceiling level.

These things are so light they will affix to plasterboard or wood panels
or whatever your ceiling is made of.

I have immense great sheets of paper faced on the bottom
and foil faced on the top, pollyfoam sheets that drop into
those galvanised steel beams that span the entire house
on the short axis. Not viable to screw anything into and
that leaves a hole with the spring toggle things. Much
more viable to double sided tape to the bottom flange
of the beams.

As I said, these things are VERY light. A self tapper would hold them onto your polyfoam. Although I don't see why you chose to make your ceiling out of such soft stuff.

Might not be the best price, I just linked to the first one I found,
not
where I bought them from. The LEDs are well spaced and they don't
exceed body temperature, so they don't fail like most LED bulbs.

Yeah, that's one big plus. Dunno what they look like
when one led dies tho as they must eventually.

As they run cool, they may well get the 50,000 hour life an LED is meant
to.

Sure, but that's still going to see some failures eventually.

Considering incandescent is 2000 hours and CFL is 8000 hours, 50000 is a
very long time indeed.

Trouble is with leds you are likely to not care about the
power used and leave them on more than you would usually.

Nope, I always use lights whenever I'm there and not otherwise.

And at £4 a strip, they're cheap to replace.

Those fully controllable led strips cost a lot more than that.

I don't need that.

And easy enough to replace a dodgy LED if one ever did fail.

Dunno, not clear how easy it is to actually change one of those LEDs in a
strip

As simple as changing any component on a circuit board.

Nope, there is no pcb with led strips.

Yes there is. How do you think they're mounted inside it?

I've got about 30 of them and have run them for 2 years.

Sure, but 2 years is **** all in the life of a house.

None in 2 years is better than other types of light.

Like hell it is with long tube fluoros. I got a lot longer
than that out of the PAR38 floods I used previously too.

And the single CFL on the bed head too.

And definitely better than any other LED I've used.

Sure, the cheap **** from china is notorious for short life.

Agreed.

It's not so much the electrical consumption cost savings that
interest me so much as the service life endurance promise standing a
much better chance of being fulfilled outside of a laboratory test
environment in the more demanding conditions typical of a domestic
pendant light fitting
complete with fancy draught excluding shade dangling in the warmest
layers of air to be found in a room basking in the warmth of a
centrally heated radiator or two.

I'm happy enough with the current crop of "60W 806Lm 120v 750 Hour
life
rated" American tungsten GLS lamp equivalent 9W LEDs where an 806 Lm
lamp
can provide the required illumination level (effectively replacing a
73W
240v 1000 hour tungsten filament GLS lamp in UK housing). It's all
these
15 and 18 watt 1500Lm LED GLS replacements for the 100W tungsten
filament
GLS lamps with their more marginal temperature tolerance that give me
pause in their deployment as a GLS alternative.

The LED version of the "100W GLS tungsten filament lamps now
starting
to
appear would seem to be a viable GLS candidate if their claimed
efficacies of 145 and 150 Lm per watt are based in reality rather
than
best hoped for efficacy.

It's been a rather disappointing wait for Cree to begin fulfilling
that
(probably ill advised) promise made by their spokesperson just over
three
years ago when they announced their record breaking achievement in
LED
efficacy. Here we are, some 50 percent further along than their upper
timescale to get 300Lm/W lamps to market, with lamps of only half
that
efficacy to show for their efforts thus far.

Still, at least *some* progress has finally materialised at long
last,
so I suppose we ought to be grateful to finally be free of the 2013
'Time
Warp' we seem to have been living in for the past 3 or 4 years. :-)
Better late than never.

At this rate of development, we'll be lucky to see the next efficacy
milestone of 200Lm/W being achieved within the next three years or
so.
Who knows? We may see a sudden spurt from Cree whereby the 200Lm/W
milestone in commercially available lamps is reached within the next
12
months. Either that or else an admission that the 303Lm/W lab results
were faked just to pressurise Philips Lighting into quitting the LED
lamp
business. :-(

They really should put sensible ratings on each LED bulb they sell.
It
should clearly state the actual electrical consumption

The high end stuff does. And states the lumens at various color temps
too.
http://www2.meethue.com/en-au/produc...specifications

(it's been mentioned in this thread that they lie), and equivalent
output
(eg "=60W incandescent". The general public don't know what a bloody
lumen is.

Sure, but when you have one already, you know if that amount of lumens
is
enough there or not.

I think in watts. I know what a 100W lightbulb is like.

I used to, but that doesn't work anymore with modern led bulbs that
you can change the color temp of to anything you like remotely.

Why not?

Because the lumens change dramatically with the color temp.
http://www2.meethue.com/en-au/produc...specifications

100W equivalent is easy to understand.

Not when the color temp changes.

I don't tend to buy adjustable ones. I buy ones with the temp I want, which is daylight white.

--
It said, "Insert disk #3," but only two will fit!

On Wed, 26 Apr 2017 22:08:33 +0100, Rod Speed wrote:

James Wilkinson Sword wrote
Rod Speed wrote
James Wilkinson Sword wrote

With a few junctions and a few phosphors, I can't see why we can't make
a real sun spectrum.

Because the sun produces a quite uniform spectrum because of the way it
emits the light.

So?

So you'll never get even close with leds.

Put several LEDs in the package,

All that does if put more spikes in the spectrum.

then add phosphors to smooth things over.

Phosphors don't do that. They have their own spikes.

I'm not asking for identical, just something vaguely similar.

It isnt even vaguely similar spectrum wise.

Adequate for a domestic situation, but that's all.

The current ones are pretty close. Double the number of LEDs or phosphors and the graph would look pretty good.

All we have is cool white and warm white.

Wrong, as always.

Apart from some specialised ones perhaps.

Nothing specialised about the ones where you can
control the color temp because they can do 16M colors.

They're not very common. Never even heard of them until you mentioned them.

But most LED bulbs only have two whites.

Most can in fact do full RGB.

Only a few like yours.

--
Ignoranus (n): A person who's both stupid and an asshole.

"James Wilkinson Sword" wrote in message
news
On Wed, 26 Apr 2017 01:04:04 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news
On Tue, 25 Apr 2017 23:56:44 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 23:04:08 +0100, Rod Speed

wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 22:12:37 +0100, Johnny B Good
wrote:

On Tue, 25 Apr 2017 14:27:29 +0100, Martin Brown wrote:

On 25/04/2017 13:27, Graham. wrote:
On Tue, 25 Apr 2017 12:25:35 +0100, "James Wilkinson Sword"
wrote:

Yes, I've googled it, but there are many different approaches.
Which
one is used in domestic LED bulbs?

Ultra-violet LED exciting a white phosphor, much the same
principle
used in florescents.

It is usually a high efficiency blue LED pump exciting a yellow
phosphor
with that mix determining the nominal colour temperature. It is
quite
peaky in the blue and more of a wide hump around the yellow. The
phosphor usually looks yellow and sits on top of the LED.

http://i.stack.imgur.com/lkyXG.png

The visible light flux out of an LED die on a high efficiency LED
these
days is about the same order of magnitude as the sun's
photosphere.

It is a lot more obvious on the devices which use a remote
phosphor.

http://www.cree.com/led-components/m...e-Phosphor.pdf

An interesting read (note the use of the expression "loosing
efficiency"
on page 8 regarding Fig 7a). Also of note is the copyright date of
this
document which is the year of their record breaking 303Lm/W led
efficacy
achievement in February/March of that year when the Cree
Spokesperson
let
slip to the trade press that such laboratory achievements typically
took
a further 18 to 24 months of development before making their début
on
store shelves for public consumption.

A simple arithmetic calculation reveals that this scheduled
development
has slipped by a rather conservatively estimated 13 months. :-( The
best
Lm/W efficacy figures I've noted recently have been around the 125
to
145
Lm/W mark. The former being a 1500Lm 12W GLS B22 2700K Warm White
lamp
I
sampled from a Home Bargains store for the princely sum of £2.99
which
turned out to have an *actual* consumption figure of 14 watts.

I thought the best LEDs were equivalent to 10W out per 1W in. Eg a
10W
LED bulb should be equivalent to a 100W incandescent. A 100W
incandescent
is 1435 lumens. So your bulb is consuming 14W to give out about
105W.
Not as good as I thought.

Since its illumination power doesn't seem as impressively bright
as
I
was expecting (even making allowances for the eye's logarithmic
response
to brightness), I rather doubt the additional 2 watts is hiking the
claimed 1500Lm to 1750Lms as one might expect if the additional 2
watts
was simply the result of overly wide tolerances in the 'electronic
ballast circuit' causing the LEDs to be overdriven to a higher than
designed Lumens output.

I have a sneaking suspicion that the claims of "1500 Lumens at 12W
(100W
eqv)" have been based on the best of a sampling of these lamps off
the
production line, possibly based on the maximum positive tolerance
limit
of the 'nominal' power consumption to boot for good measure (+10%?
=
13.2W) so might more typically be nearer the 110Lm/W mark than to
the
claimed 125Lm/W figure. Even the claimed efficacy is not a
particularly
massive improvement over the 81Lm/W efficacy figures typical of
many
LED
GLS lamps of just over three years ago.

Companies lie, they always do. Cameras state x MP, and if you take
a
photo at full resolution, it's ****. Hard disks don't use
gigabytes,
but
billions of bytes, shaving off a little.

The 145Lm/W lamps I saw were the grossly overpriced 1600Lm LES 11W
examples being offered by Asda. I might have considered buying one
if
they'd been more sanely priced but at something like 10 to 18 quid
a
pop
(I didn't bother trying to pin the confusing shelf price labelling
down
any tighter than that - it was enough to know that it was at least
3
times pricier than I'd been prepared to pay in Home and Bargain), I
wasn't in the least bit tempted.

I'm currently using this sort of thing:
http://www.ebay.co.uk/itm/231644564446

I want complete remote control of on/off, color temp and dimming, by
voice.

I don't see the need for that.

I do, I don't want the same light level all the time that its useful to
have
the light on.

I prefer a brighter light on what I am eating than when I am typing
after
eating and a different light level when watching recorded videos etc.

Odd, I just like it bright all the time so I can see what I'm doing.

I do want to do that when eating or repairing stuff,
but not when using the computer or watching videos.

Why not?

Works better to have the screen the brightest in that situation,
its not washed out by the maximum brightness room lighting.

I make the TV/monitor bright enough to see in that amount of ambient
light. The exception is my bedroom where I have a dimmer light so I
don't
wake up and get dazzled.

Yeah, tho I prefer a soft start there, but want full
brightness so I can read the non backlit scales better.

I should get some automatically recording scales
but currently havent found any that are even that
reproducible so they read the same thing if you
weigh yourself say 5 times in a row. Had a hell
of a job finding a decent set of digital scales
that don't have any recording capability at all.

I don't have scales in the bedroom, don't they normally live in the
bathroom?

I don't give a flying red **** what is normal,
I do what works best for me.

Anyway why are you so obsessed with your weight?

I'm not. But it's the reason I am within the best BMI range and you arent,
lard arse.

All my rooms have one or more PIR/daylight sensors. They come on if
it's dark and someone (or a pet) is moving in the room. I never
manually turn on a light.

Too crude. I don't want the same light level all the time when its
dark.

Don't when I get up either. I prefer to light to fade up over a
second or so it isnt too bright initially but is full brightness a
bit later when I weigh myself so I can see the scale properly.

Bedroom dim, every other room bright. Simpler that way.

Not viable when you want full brightness for reading the scales.

Your eyes must really suck.

And much more convenient physically too. The Hue Lightstrip Plus
starts
with a 2M strip and has 1M plug in extensions with up to 8 allowed
and
they go in the standard led strip extrusions that are much less bulky
than
yours and you can get in single lengths up to 10m or more in length
so
you can have the one thing covering the entire long axis of even the
longest room and with joiners to go for 100m in total if you need to.

Mine are very easy. You plug in one strip to the power. Then they
all
join to that one. As for physical mounting, ONE single screw in a
little clip supports each strip.

Useless for me because the only sensible place to attach
anything is to the base flange of the galvanised steel beams
that form the entire roof/ceiling structure at ceiling level.

These things are so light they will affix to plasterboard or wood panels
or whatever your ceiling is made of.

I have immense great sheets of paper faced on the bottom
and foil faced on the top, pollyfoam sheets that drop into
those galvanised steel beams that span the entire house
on the short axis. Not viable to screw anything into and
that leaves a hole with the spring toggle things. Much
more viable to double sided tape to the bottom flange
of the beams.

As I said, these things are VERY light. A self tapper would hold them
onto your polyfoam. Although I don't see why you chose to make your
ceiling out of such soft stuff.

Might not be the best price, I just linked to the first one I found,
not
where I bought them from. The LEDs are well spaced and they don't
exceed body temperature, so they don't fail like most LED bulbs.

Yeah, that's one big plus. Dunno what they look like
when one led dies tho as they must eventually.

As they run cool, they may well get the 50,000 hour life an LED is
meant
to.

Sure, but that's still going to see some failures eventually.

Considering incandescent is 2000 hours and CFL is 8000 hours, 50000 is a
very long time indeed.

Trouble is with leds you are likely to not care about the
power used and leave them on more than you would usually.

Nope, I always use lights whenever I'm there and not otherwise.

And at £4 a strip, they're cheap to replace.

Those fully controllable led strips cost a lot more than that.

I don't need that.

And easy enough to replace a dodgy LED if one ever did fail.

Dunno, not clear how easy it is to actually change one of those LEDs in
a
strip

As simple as changing any component on a circuit board.

Nope, there is no pcb with led strips.

Yes there is. How do you think they're mounted inside it?

I've got about 30 of them and have run them for 2 years.

Sure, but 2 years is **** all in the life of a house.

None in 2 years is better than other types of light.

Like hell it is with long tube fluoros. I got a lot longer
than that out of the PAR38 floods I used previously too.

And the single CFL on the bed head too.

And definitely better than any other LED I've used.

Sure, the cheap **** from china is notorious for short life.

Agreed.

It's not so much the electrical consumption cost savings that
interest me so much as the service life endurance promise standing
a
much better chance of being fulfilled outside of a laboratory test
environment in the more demanding conditions typical of a domestic
pendant light fitting
complete with fancy draught excluding shade dangling in the warmest
layers of air to be found in a room basking in the warmth of a
centrally heated radiator or two.

I'm happy enough with the current crop of "60W 806Lm 120v 750 Hour
life
rated" American tungsten GLS lamp equivalent 9W LEDs where an 806
Lm
lamp
can provide the required illumination level (effectively replacing
a
73W
240v 1000 hour tungsten filament GLS lamp in UK housing). It's all
these
15 and 18 watt 1500Lm LED GLS replacements for the 100W tungsten
filament
GLS lamps with their more marginal temperature tolerance that give
me
pause in their deployment as a GLS alternative.

The LED version of the "100W GLS tungsten filament lamps now
starting
to
appear would seem to be a viable GLS candidate if their claimed
efficacies of 145 and 150 Lm per watt are based in reality rather
than
best hoped for efficacy.

It's been a rather disappointing wait for Cree to begin fulfilling
that
(probably ill advised) promise made by their spokesperson just over
three
years ago when they announced their record breaking achievement in
LED
efficacy. Here we are, some 50 percent further along than their
upper
timescale to get 300Lm/W lamps to market, with lamps of only half
that
efficacy to show for their efforts thus far.

Still, at least *some* progress has finally materialised at long
last,
so I suppose we ought to be grateful to finally be free of the 2013
'Time
Warp' we seem to have been living in for the past 3 or 4 years. :-)
Better late than never.

At this rate of development, we'll be lucky to see the next
efficacy
milestone of 200Lm/W being achieved within the next three years or
so.
Who knows? We may see a sudden spurt from Cree whereby the 200Lm/W
milestone in commercially available lamps is reached within the
next
12
months. Either that or else an admission that the 303Lm/W lab
results
were faked just to pressurise Philips Lighting into quitting the
LED
lamp
business. :-(

They really should put sensible ratings on each LED bulb they sell.
It
should clearly state the actual electrical consumption

The high end stuff does. And states the lumens at various color temps
too.
http://www2.meethue.com/en-au/produc...specifications

(it's been mentioned in this thread that they lie), and equivalent
output
(eg "=60W incandescent". The general public don't know what a
bloody
lumen is.

Sure, but when you have one already, you know if that amount of
lumens
is
enough there or not.

I think in watts. I know what a 100W lightbulb is like.

I used to, but that doesn't work anymore with modern led bulbs that
you can change the color temp of to anything you like remotely.

Why not?

Because the lumens change dramatically with the color temp.
http://www2.meethue.com/en-au/produc...specifications

100W equivalent is easy to understand.

Not when the color temp changes.

I don't tend to buy adjustable ones.

I prefer to be able to vary that, because I
don't use the same color temp all the time.

I buy ones with the temp I want, which is daylight white.

The previous lights were a combination of 4' fluoros and
PAR38 floods. I prefer different color temps in some
situations most obviously when doing fine repair work
and when watching recorded video or reading a book etc.

"James Wilkinson Sword" wrote in message
news
On Wed, 26 Apr 2017 22:08:33 +0100, Rod Speed
wrote:

James Wilkinson Sword wrote
Rod Speed wrote
James Wilkinson Sword wrote

With a few junctions and a few phosphors, I can't see why we can't
make
a real sun spectrum.

Because the sun produces a quite uniform spectrum because of the way it
emits the light.

So?

So you'll never get even close with leds.

Put several LEDs in the package,

All that does if put more spikes in the spectrum.

then add phosphors to smooth things over.

Phosphors don't do that. They have their own spikes.

I'm not asking for identical, just something vaguely similar.

It isnt even vaguely similar spectrum wise.

Adequate for a domestic situation, but that's all.

The current ones are pretty close. Double the number of LEDs or phosphors
and the graph would look pretty good.

Nope.

All we have is cool white and warm white.

Wrong, as always.

Apart from some specialised ones perhaps.

Nothing specialised about the ones where you can
control the color temp because they can do 16M colors.

They're not very common.

Irrelevant to whether they are specialised or not.

Never even heard of them until you mentioned them.

Sure, they havent been around all that long yet.

But most LED bulbs only have two whites.

Most can in fact do full RGB.

Only a few like yours.

There are heaps of them than can do full RGB

On Sat, 06 May 2017 00:58:27 +0100, Rod Speed wrote:



"James Wilkinson Sword" wrote in message
news
On Wed, 26 Apr 2017 20:26:12 +0100, Rod Speed
wrote:

NY wrote
James Wilkinson Sword wrote

As far as I am aware most approaches revolve around the doping of the
part which emits light. Normally more than one led is used each giving
off a fairly narrow range of colour, and then combining them to make a
perceptually white light.

I have also seen some that refine this a bit with internal filtering,
but essentially, as far as I am aware, nobody has made a single led
element that has a sufficiently wide band output to give white on its
own.

We've just got a couple of Philips Hue bulbs which can be set to a
variety
of different colours (as well as being dimmable), presumably by varying
the proportions of different coloured LEDs.

I'm in the process of changing over to Hues entirely.

It was my wife's idea and they are a bit of a gimmick. I tend to use the
one in my study mainly on fairly neutral white (ranging between warm
white
and daylight)

I prefer the cool white end myself. Surprised me a bit because
I used to use PAR38 floods inside the house because I preferred
the light from those to the long tube fluoros with daylight tubes.

but my wife likes to set hers to lurid purple or red as background
lighting when she reads on her Kindle (which produces its own light, so
the colour of the room lighting doesn't affect the colour of the text).

Urk don't do that at all myself.

We got them partly to test the technology, controlling by mobile phone
app
or Alexa voice recognition;

I did it mainly to move to complete automation of the lights
and other stuff like the electric blanket etc. Ideally I would
prefer to operate without having to ever use light switches
at all and have the system work out when someone is in a
particular location and decide if light is required there etc.

Not totally automatable probably unless I can work out some
time based rules too, because I prefer to have full light when
I am actually eating, but not when using the computer or
watching video and that's all done in the one place.

All my lights simply operate by motion sensor and light sensor

I prefer different light levels for different situations.

Are you female?

With different time limits for each room. Eg the bedroom is shorter so it
goes off shortly after I get into bed. The living room is longer to allow
for me sitting still while watching TV.

Trouble is that the time isnt just determined by the location.

Is for me. Bedroom is for sleeping, I want it to go off just after I get into bed. Everywhere else I want it to stay on while I'm in the room and not moving for a while.

I don't have the problem you do with wanting different brightnesses for
different tasks, I just like it bright all the time unless I'm sleeping.

I prefer it much brighter when I am say dismantling
and fixing something than when watching TV etc.

The TV emits it's own light, why would you need the room dark?

What is interesting is that even the whitest light, which appears
slightly blue to the eye,

Doesn't to me for some reason.

Does to me if I've been looking at warm lights recently. But the
headlight bulbs in BMWs always look blue, probably because they are. They
should be outlawed. Too much like an emergency vehicle.

Our emergency vehicles always have both red and blue
so they stand out like dogs balls and no cars ever look
anything like them. Those lights are much higher too,
at roof level and flashing too.

Same here, but still, seeing a blue light makes me look.

With the Light strip Plus that I have
two of now in the kitchen, I can't find the white that just has the big
white leds on, the other two colored leds are on at a low level too.

I've only been driving them with the apps so far tho, not by programming.

shows on a digital camera as being a little warmer than full sunlight
(about 5000K). A "daylight" CFL alongside it (OK, I was curious so I did
a
comparison!) looks slightly warmer by eye but the camera sees it as
being
cooler than the LED.

This goes to show that the eye is a very poor indicator of colour
temperature, and that it has a lot of auto-
adjustment built into the eye/brain mechanism.

Of course, if the digital camera is set to auto-white-balance rather
than
a preset "tungsten", "fluorescent", "sunlight", "shade", it adjusts too.

Some time I'll have to try some test photos using the same Hue bulb on
various colours and brightnesses, and see what the colour rendition of
real subjects is like in various conditions.

When I want to put stuff on one of the facebook buy sell swap
groups or ebay etc I normally just put on a table outside in the sun.

Can't do that in the UK, you'd have to wait a few weeks.

Yep, not surprising those of you lot with a clue migrate.

I wish more of them would, it's too ****ing crowded here. Why is Australia less densely populated when you have the better weather? They're even building new housing estates here with single lane roads to save space. Anybody stops to deliver parcels and nobody can get through.

Would be more convenient to have a dedicated
table inside with a Hue or two I spose.

When I've done it in the past, using sunlight, shade, tungsten bulb,
warm
white fluorescent tube, daylight CFL and daylight LED GU10, the camera's
auto-white has made them all look fairly similar in terms of overall
colour cast, but red objects tend to be a bit darker and less vibrant
with
CFL and LED.

I dread to think what the spectrum of some of these bulbs is like,

Yeah, bet its really weird.

but I bet there are a lot of holes in the spectrum compared with a
black-body radiator like a tungsten bulb or the sun (ignoring very small
gaps in sunlight due to absorbtion lines of the atmosphere). I dimmed a
tungsten bulb from full brightness to barely lit, using a conventional
thyristor dimmer, and the camera's auto-white and auto-exposure made all
the test photos look pretty well identical, which is how it *ought* to
be
with LEDs and CFLs.

I presume LEDs vary their brightness by varying the duty cycle of a
square wave

IMO its much more likely to be done by varying the
constant current but I don't know that for a fact. It
would be easy to check with the Lightstrip Plus using
a CRO, must dig mine out and see what they do.

(and maybe even varying its frequency too).

Dunno what the point of varying the frequency would be.

Same pulse width more often to make it brighter?

That's the duty cycle, not the frequency.

Higher frequency with same pulse width = more duty cycle.

I've always wondered why this doesn't causing any banding or beating
when
those lights are used as studio lights in a TV studio.

Yeah, that's the other reason for varying the current and not doing PWM
with those, That inevitably going to be a major problem with
photographing
stuff, even for domestic situations rather than professional with digital
cameras.

Car lights look damn stupid when being filmed (and some annoy me when I'm
driving about as I can see the flicker). You'd think the more expensive
cars would use proper LEDs without flashing.

Not economically feasible with lights that bright.

I said expensive cars. And my 4 quid 90 watt equivalent room lights don't flicker at all.

--
Two things are infinite: the universe and human stupidity. And I'm not sure about the universe. - Albert Einstein

"James Wilkinson Sword" wrote in message
news
On Sat, 06 May 2017 00:58:27 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news
On Wed, 26 Apr 2017 20:26:12 +0100, Rod Speed
wrote:

NY wrote
James Wilkinson Sword wrote

As far as I am aware most approaches revolve around the doping of
the
part which emits light. Normally more than one led is used each
giving
off a fairly narrow range of colour, and then combining them to make
a
perceptually white light.

I have also seen some that refine this a bit with internal
filtering,
but essentially, as far as I am aware, nobody has made a single led
element that has a sufficiently wide band output to give white on
its
own.

We've just got a couple of Philips Hue bulbs which can be set to a
variety
of different colours (as well as being dimmable), presumably by
varying
the proportions of different coloured LEDs.

I'm in the process of changing over to Hues entirely.

It was my wife's idea and they are a bit of a gimmick. I tend to use
the
one in my study mainly on fairly neutral white (ranging between warm
white
and daylight)

I prefer the cool white end myself. Surprised me a bit because
I used to use PAR38 floods inside the house because I preferred
the light from those to the long tube fluoros with daylight tubes.

but my wife likes to set hers to lurid purple or red as background
lighting when she reads on her Kindle (which produces its own light,
so
the colour of the room lighting doesn't affect the colour of the
text).

Urk don't do that at all myself.

We got them partly to test the technology, controlling by mobile phone
app
or Alexa voice recognition;

I did it mainly to move to complete automation of the lights
and other stuff like the electric blanket etc. Ideally I would
prefer to operate without having to ever use light switches
at all and have the system work out when someone is in a
particular location and decide if light is required there etc.

Not totally automatable probably unless I can work out some
time based rules too, because I prefer to have full light when
I am actually eating, but not when using the computer or
watching video and that's all done in the one place.

All my lights simply operate by motion sensor and light sensor

I prefer different light levels for different situations.

Are you female?

No point in asking if you are a pathetic excuse for a troll, the answer is
obvious.

With different time limits for each room. Eg the bedroom is shorter so
it
goes off shortly after I get into bed. The living room is longer to
allow
for me sitting still while watching TV.

Trouble is that the time isnt just determined by the location.

Is for me.

Nope.

Bedroom is for sleeping, I want it to go off just after I get into bed.

Pity about when you are in the bedroom but not in the bed.

Everywhere else I want it to stay on while I'm in the room and not moving
for a while.

Not possible to work out when you have gone to sleep in front of the TV.

I don't have the problem you do with wanting different brightnesses for
different tasks, I just like it bright all the time unless I'm sleeping.

I prefer it much brighter when I am say dismantling
and fixing something than when watching TV etc.

The TV emits it's own light, why would you need the room dark?

I didn't say I need the room dark. But it works better
if its not as bright as when I am dismantling and
fixing something or looking for something.

What is interesting is that even the whitest light, which appears
slightly blue to the eye,

Doesn't to me for some reason.

Does to me if I've been looking at warm lights recently. But the
headlight bulbs in BMWs always look blue, probably because they are.
They
should be outlawed. Too much like an emergency vehicle.

Our emergency vehicles always have both red and blue
so they stand out like dogs balls and no cars ever look
anything like them. Those lights are much higher too,
at roof level and flashing too.

Same here, but still, seeing a blue light makes me look.

I only look when its red and blue and flashing.

With the Light strip Plus that I have
two of now in the kitchen, I can't find the white that just has the big
white leds on, the other two colored leds are on at a low level too.

I've only been driving them with the apps so far tho, not by
programming.

shows on a digital camera as being a little warmer than full sunlight
(about 5000K). A "daylight" CFL alongside it (OK, I was curious so I
did
a
comparison!) looks slightly warmer by eye but the camera sees it as
being
cooler than the LED.

This goes to show that the eye is a very poor indicator of colour
temperature, and that it has a lot of auto-
adjustment built into the eye/brain mechanism.

Of course, if the digital camera is set to auto-white-balance rather
than
a preset "tungsten", "fluorescent", "sunlight", "shade", it adjusts
too.

Some time I'll have to try some test photos using the same Hue bulb on
various colours and brightnesses, and see what the colour rendition of
real subjects is like in various conditions.

When I want to put stuff on one of the facebook buy sell swap
groups or ebay etc I normally just put on a table outside in the sun.

Can't do that in the UK, you'd have to wait a few weeks.

Yep, not surprising those of you lot with a clue migrate.

I wish more of them would, it's too ****ing crowded here.

No one is stupid enough to let them anymore except the EU
and its infested with wogs that don't even speak english.

Why is Australia less densely populated

It isnt in the capital citys and CBDs etc.

when you have the better weather?

We only let in those that are any use to us.

You poms have never been any use since the war.

They're even building new housing estates here with single lane roads to
save space. Anybody stops to deliver parcels and nobody can get through.

That's because anyone with even half a clue migrated and
you lot ended up with the dregs like you and harry that not
only can't work out where viable jobs on the soggy little
frigid island are, you cant even work out the most basic stuff
like how wide the streets need to be in a housing estate.

Or design a viable car either.

Would be more convenient to have a dedicated
table inside with a Hue or two I spose.

When I've done it in the past, using sunlight, shade, tungsten bulb,
warm
white fluorescent tube, daylight CFL and daylight LED GU10, the
camera's
auto-white has made them all look fairly similar in terms of overall
colour cast, but red objects tend to be a bit darker and less vibrant
with
CFL and LED.

I dread to think what the spectrum of some of these bulbs is like,

Yeah, bet its really weird.

but I bet there are a lot of holes in the spectrum compared with a
black-body radiator like a tungsten bulb or the sun (ignoring very
small
gaps in sunlight due to absorbtion lines of the atmosphere). I dimmed
a
tungsten bulb from full brightness to barely lit, using a conventional
thyristor dimmer, and the camera's auto-white and auto-exposure made
all
the test photos look pretty well identical, which is how it *ought* to
be
with LEDs and CFLs.

I presume LEDs vary their brightness by varying the duty cycle of a
square wave

IMO its much more likely to be done by varying the
constant current but I don't know that for a fact. It
would be easy to check with the Lightstrip Plus using
a CRO, must dig mine out and see what they do.

(and maybe even varying its frequency too).

Dunno what the point of varying the frequency would be.

Same pulse width more often to make it brighter?

That's the duty cycle, not the frequency.

Higher frequency with same pulse width = more duty cycle.

There's a reason it aint done like that.

I've always wondered why this doesn't causing any banding or beating
when those lights are used as studio lights in a TV studio.

Yeah, that's the other reason for varying the current and not doing PWM
with those, That inevitably going to be a major problem with
photographing
stuff, even for domestic situations rather than professional with
digital
cameras.

Car lights look damn stupid when being filmed (and some annoy me when
I'm
driving about as I can see the flicker). You'd think the more expensive
cars would use proper LEDs without flashing.

Not economically feasible with lights that bright.

I said expensive cars.

Not economically feasible with those either.

And my 4 quid 90 watt equivalent room lights don't flicker at all.

That's **** all light. Useless for car headlights.

On Tue, 16 May 2017 20:55:30 +0100, Rod Speed wrote:



"James Wilkinson Sword" wrote in message
news
On Tue, 25 Apr 2017 23:38:31 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 23:07:38 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 22:08:34 +0100, Rod Speed

wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 21:01:37 +0100, Rod Speed

wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 19:34:38 +0100, Rod Speed

wrote:

James Wilkinson Sword wrote
Graham. wrote
James Wilkinson Sword wrote

Yes, I've googled it, but there are many different approaches.
Which one is used in domestic LED bulbs?

Ultra-violet LED exciting a white phosphor,
much the same principle used in florescents.

That's what I would have assumed, but when you
look at a switched off white LED, it's not white.

All that means is that it isnt white when it doesn't have UV
falling
on it and that the protective outer isnt the phosphor itself.

I would have expected it to have a white coating that
can be seen like on a switched off fluorescent tube.

The difference is that leds don't have glass as the protective
outer.

Those adjustable-by-remote ones you have, just how many colours
can
you
make?

They claim 16M

Do they only have R G and B emitters,

Nope. The strips where the leds are visible have one big led and a
couple
of smaller RGB ones. Not clear why there is more than one RGB one,
presumably because they arent anything like as bright as the white
one.

Just discovered I can't actually take a photo of the strip with the
leds
lit in the dark it completely ****s the exposure system in the
phone.

Use a real camera

Don't have one anymore and wouldn't have any film for it even if I
did.

I meant a real digital camera, with proper options like manual control
of
focussing and aperture for situations like this.

Don't bother with those, stupid waste of money given that the
phone does almost all I ever need and is with me all the time.

It's a child's toy compared to a proper camera.

Couldn't care less. It does what I want to do almost all of
the time and the times when it doesn't as so few that its not
worth having something more capable for those situation.

There likely is an app that allows full manual control
of the exposure but I havent bothered to look because
its not worth my time to even look for one.

Only any good to take a photo to show someone something, prove something
happened etc.

Its good for a hell of a lot more than that, like being a handy
video recorder that's with me all the time, handy for taking a
photo of shelf price stickers instead of recording prices any
other way, handy for taking photos of ID plates, handy for
taking photos of stuff that I would otherwise have to lie
flat on my face on the ground to see, handy for stuff with
print on it so fine and such poor contrast that I cant even
read, etc etc etc.

I can't say I need a camera at random like that.

Only because you are too stupid to think of using it for that.

No, it's just not necessary.

Only if I'm going out somewhere and want to take pictures, so I just take
a proper camera.

You cant always predict when you will want to take
a picture, most obviously when some fool runs into
your car and you need to take a picture of the eejut
in case he later claims he wasn't there etc.

That's why there's a dashcam in my car. Mind you before I had one, the insurance companies usually worked out whose fault it was from the descriptions from each driver and the damage caused to each vehicle. I've never had a lie successfully used against me in a crash.

I see no reason to ever carry a phone with me,

Yes, you are that terminal a ****wit.

my mobile actually stays at home almost all the time.

Yes, you are that terminal a ****wit.

I occasionally take it with me if I know I need to phone someone on the
way,

But you cant always anticipate when you will need to do that.

Yes I can. If I'm travelling 400 miles to visit a relative and want to phone them to tell them when I'll be arriving. But driving and walking and running in my local area, absolutely no need for a phone.

otherwise I prefer not to have it get lost, broken, wet, stolen, etc.

I've never ever had that happen to any of mine.

In Scotland it rains a lot, the chances of it getting wet are high. Also I can't be bothered choosing clothes with deep enough pockets to carry a phone safely. Even if they are deep, when I sit down, say in the car, the phone is likely to fall out.

The quality is awful.

Even sillier than you usually manage.

Well for gullible fools like you that spend hundreds on an Iphone it might
be good quality.

Much better quality than this **** below.

What **** below?

I just pay 10 quid for one. It texts, it calls, and it'll take a good
enough picture if I have to, say for evidence of a car crash.

Not when you have left it at home it wont.

I take it with me on a long journey / holiday etc.

Simply not room on a phone for a proper lens.

Don't need a proper lens, I don't take that sort of photo.

A phone is not a camera, it's a handy thing which can take a dodgy
photo
at a push.

Nothing dodgy about any of the ones I have taken.

Show me an example of a quality photo from your phone.

I don't bother with that sort of photo. There are plenty online.

And show me something like an animal in the distance you've zoomed in
on.

Don't take that sort of photo.

Take a picture of a galah in a tree etc.

No galahs in my trees currently.

Have a look on Youtube of the truly awful quality videos people take with
their phones.

Irrelevant to what the best of them are like.

The best of them cost as much as a car.

--
Some people are like slinkies, not really good for anything, but they bring a smile to your face when pushed down the stairs.

"James Wilkinson Sword" wrote in message
news
On Tue, 16 May 2017 20:55:30 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news
On Tue, 25 Apr 2017 23:38:31 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 23:07:38 +0100, Rod Speed

wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 22:08:34 +0100, Rod Speed

wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 21:01:37 +0100, Rod Speed

wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 19:34:38 +0100, Rod Speed

wrote:

James Wilkinson Sword wrote
Graham. wrote
James Wilkinson Sword wrote

Yes, I've googled it, but there are many different
approaches.
Which one is used in domestic LED bulbs?

Ultra-violet LED exciting a white phosphor,
much the same principle used in florescents.

That's what I would have assumed, but when you
look at a switched off white LED, it's not white.

All that means is that it isnt white when it doesn't have UV
falling
on it and that the protective outer isnt the phosphor itself.

I would have expected it to have a white coating that
can be seen like on a switched off fluorescent tube.

The difference is that leds don't have glass as the protective
outer.

Those adjustable-by-remote ones you have, just how many colours
can
you
make?

They claim 16M

Do they only have R G and B emitters,

Nope. The strips where the leds are visible have one big led and
a
couple
of smaller RGB ones. Not clear why there is more than one RGB
one,
presumably because they arent anything like as bright as the
white
one.

Just discovered I can't actually take a photo of the strip with
the
leds
lit in the dark it completely ****s the exposure system in the
phone.

Use a real camera

Don't have one anymore and wouldn't have any film for it even if I
did.

I meant a real digital camera, with proper options like manual
control
of
focussing and aperture for situations like this.

Don't bother with those, stupid waste of money given that the
phone does almost all I ever need and is with me all the time.

It's a child's toy compared to a proper camera.

Couldn't care less. It does what I want to do almost all of
the time and the times when it doesn't as so few that its not
worth having something more capable for those situation.

There likely is an app that allows full manual control
of the exposure but I havent bothered to look because
its not worth my time to even look for one.

Only any good to take a photo to show someone something, prove
something
happened etc.

Its good for a hell of a lot more than that, like being a handy
video recorder that's with me all the time, handy for taking a
photo of shelf price stickers instead of recording prices any
other way, handy for taking photos of ID plates, handy for
taking photos of stuff that I would otherwise have to lie
flat on my face on the ground to see, handy for stuff with
print on it so fine and such poor contrast that I cant even
read, etc etc etc.

I can't say I need a camera at random like that.

Only because you are too stupid to think of using it for that.

No, it's just not necessary.

Only if I'm going out somewhere and want to take pictures, so I just
take
a proper camera.

You cant always predict when you will want to take
a picture, most obviously when some fool runs into
your car and you need to take a picture of the eejut
in case he later claims he wasn't there etc.

That's why there's a dashcam in my car.

Pity about the other stuff that doesn't happen within
view of your car, like the Manchester bombing.

Mind you before I had one, the insurance companies usually worked out
whose fault it was from the descriptions from each driver and the damage
caused to each vehicle.

They didn't bother, just covered their own insured's damage
unless the driver at fault stood out like dogs balls.

I've never had a lie successfully used against me in a crash.

Because they didn't bother to try to work at who
was at fault, just covered their own insured's damage
unless the driver at fault stood out like dogs balls.

I see no reason to ever carry a phone with me,

Yes, you are that terminal a ****wit.

my mobile actually stays at home almost all the time.

Yes, you are that terminal a ****wit.

I occasionally take it with me if I know I need to phone someone on the
way,

But you cant always anticipate when you will need to do that.

Yes I can.

Even sillier than you usually manage with faults in the car or when
public transport stops working the way you assumed it would like
with BA cancelling all flights when their system ends up flat on its face.

If I'm travelling 400 miles to visit a relative and want to phone them to
tell them when I'll be arriving. But driving and walking and running in
my local area, absolutely no need for a phone.

Even sillier than you usually manage. When out very early in the
morning, I came across one fellow quite literally lying in the middle
of the road, completely unconscious, with blood leaking out of
one of his ears and forming quite a pool of blood on the road.

Very much better to be able to call the cops and ambos
with my phone than have to try to get someone in one
of the houses close to answer the door and ring them,
with me not being able to stand next to him and assist
him and avoid someone running over him because
they didn't notice him lying there until it was too late.

Same with that loony that quite literally burned down the
house just a couple of houses away. Much better to be
able to notice her acting suspiciously around the house
of someone I know very well, call them using my mobile,
have them tell me that they are hundreds of miles away
and that they havent organised anyone to look after pets
left in the house, and call the cops while staying out of
view of the loony so she doesn't just bugger off when
she notices someone observing her.

otherwise I prefer not to have it get lost, broken, wet, stolen, etc.

I've never ever had that happen to any of mine.

In Scotland it rains a lot, the chances of it getting wet are high.

Completely trivial to get a waterproof case for the phone.

Also I can't be bothered choosing clothes with deep enough pockets to
carry a phone safely.

All of mine do that fine without any choosing.

Even if they are deep, when I sit down, say in the car, the phone is
likely to fall out.

Mine has never done that and in fact is a complete
pain in the arse to get out of the pocket when sitting
in the car and impossible when driving, you have to stop.

The quality is awful.

Even sillier than you usually manage.

Well for gullible fools like you that spend hundreds on an Iphone it
might
be good quality.

Much better quality than this **** below.

What **** below?

Your **** below.

I just pay 10 quid for one. It texts, it calls, and it'll take a good
enough picture if I have to, say for evidence of a car crash.

Not when you have left it at home it wont.

I take it with me on a long journey / holiday etc.

You just said you don't. And that is microscopic
subset of the trips you make anyway.

Simply not room on a phone for a proper lens.

Don't need a proper lens, I don't take that sort of photo.

A phone is not a camera, it's a handy thing which can take a dodgy
photo
at a push.

Nothing dodgy about any of the ones I have taken.

Show me an example of a quality photo from your phone.

I don't bother with that sort of photo. There are plenty online.

And show me something like an animal in the distance you've zoomed in
on.

Don't take that sort of photo.

Take a picture of a galah in a tree etc.

No galahs in my trees currently.

Have a look on Youtube of the truly awful quality videos people take
with
their phones.

Irrelevant to what the best of them are like.

The best of them cost as much as a car.

Even sillier than you usually manage even with the steaming
turds with wheels you are actually stupid enough to have.

On Wed, 17 May 2017 23:43:03 +0100, Rod Speed wrote:



"James Wilkinson Sword" wrote in message
news
On Wed, 26 Apr 2017 01:04:04 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 23:56:44 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 23:04:08 +0100, Rod Speed

wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 22:12:37 +0100, Johnny B Good
wrote:

On Tue, 25 Apr 2017 14:27:29 +0100, Martin Brown wrote:

On 25/04/2017 13:27, Graham. wrote:
On Tue, 25 Apr 2017 12:25:35 +0100, "James Wilkinson Sword"
wrote:

Yes, I've googled it, but there are many different approaches.
Which
one is used in domestic LED bulbs?

Ultra-violet LED exciting a white phosphor, much the same
principle
used in florescents.

It is usually a high efficiency blue LED pump exciting a yellow
phosphor
with that mix determining the nominal colour temperature. It is
quite
peaky in the blue and more of a wide hump around the yellow. The
phosphor usually looks yellow and sits on top of the LED.

http://i.stack.imgur.com/lkyXG.png

The visible light flux out of an LED die on a high efficiency LED
these
days is about the same order of magnitude as the sun's
photosphere.

It is a lot more obvious on the devices which use a remote
phosphor.

http://www.cree.com/led-components/m...e-Phosphor.pdf

An interesting read (note the use of the expression "loosing
efficiency"
on page 8 regarding Fig 7a). Also of note is the copyright date of
this
document which is the year of their record breaking 303Lm/W led
efficacy
achievement in February/March of that year when the Cree
Spokesperson
let
slip to the trade press that such laboratory achievements typically
took
a further 18 to 24 months of development before making their début
on
store shelves for public consumption.

A simple arithmetic calculation reveals that this scheduled
development
has slipped by a rather conservatively estimated 13 months. :-( The
best
Lm/W efficacy figures I've noted recently have been around the 125
to
145
Lm/W mark. The former being a 1500Lm 12W GLS B22 2700K Warm White
lamp
I
sampled from a Home Bargains store for the princely sum of £2.99
which
turned out to have an *actual* consumption figure of 14 watts.

I thought the best LEDs were equivalent to 10W out per 1W in. Eg a
10W
LED bulb should be equivalent to a 100W incandescent. A 100W
incandescent
is 1435 lumens. So your bulb is consuming 14W to give out about
105W.
Not as good as I thought.

Since its illumination power doesn't seem as impressively bright
as
I
was expecting (even making allowances for the eye's logarithmic
response
to brightness), I rather doubt the additional 2 watts is hiking the
claimed 1500Lm to 1750Lms as one might expect if the additional 2
watts
was simply the result of overly wide tolerances in the 'electronic
ballast circuit' causing the LEDs to be overdriven to a higher than
designed Lumens output.

I have a sneaking suspicion that the claims of "1500 Lumens at 12W
(100W
eqv)" have been based on the best of a sampling of these lamps off
the
production line, possibly based on the maximum positive tolerance
limit
of the 'nominal' power consumption to boot for good measure (+10%?
=
13.2W) so might more typically be nearer the 110Lm/W mark than to
the
claimed 125Lm/W figure. Even the claimed efficacy is not a
particularly
massive improvement over the 81Lm/W efficacy figures typical of
many
LED
GLS lamps of just over three years ago.

Companies lie, they always do. Cameras state x MP, and if you take
a
photo at full resolution, it's ****. Hard disks don't use
gigabytes,
but
billions of bytes, shaving off a little.

The 145Lm/W lamps I saw were the grossly overpriced 1600Lm LES 11W
examples being offered by Asda. I might have considered buying one
if
they'd been more sanely priced but at something like 10 to 18 quid
a
pop
(I didn't bother trying to pin the confusing shelf price labelling
down
any tighter than that - it was enough to know that it was at least
3
times pricier than I'd been prepared to pay in Home and Bargain), I
wasn't in the least bit tempted.

I'm currently using this sort of thing:
http://www.ebay.co.uk/itm/231644564446

I want complete remote control of on/off, color temp and dimming, by
voice.

I don't see the need for that.

I do, I don't want the same light level all the time that its useful to
have
the light on.

I prefer a brighter light on what I am eating than when I am typing
after
eating and a different light level when watching recorded videos etc.

Odd, I just like it bright all the time so I can see what I'm doing..

I do want to do that when eating or repairing stuff,
but not when using the computer or watching videos.

Why not?

Works better to have the screen the brightest in that situation,
its not washed out by the maximum brightness room lighting.

Nope, it's the same brightness as the rest of the room, much more comfortable to look at.

I make the TV/monitor bright enough to see in that amount of ambient
light. The exception is my bedroom where I have a dimmer light so I
don't wake up and get dazzled.

Yeah, tho I prefer a soft start there, but want full
brightness so I can read the non backlit scales better.

I should get some automatically recording scales
but currently havent found any that are even that
reproducible so they read the same thing if you
weigh yourself say 5 times in a row. Had a hell
of a job finding a decent set of digital scales
that don't have any recording capability at all.

I don't have scales in the bedroom, don't they normally live in the
bathroom?

I don't give a flying red **** what is normal,
I do what works best for me.

You could stop being such a cheapskate and get backlit scales.

Anyway why are you so obsessed with your weight?

I'm not. But it's the reason I am within the best BMI range and you arent,
lard arse.

Life is way more comfortable if you eat what your body wants you to. You have a natural BMI according to your genetics, if you try to change it you're constantly depriving yourself of food.

Sure, but when you have one already, you know if that amount of
lumens
is
enough there or not.

I think in watts. I know what a 100W lightbulb is like.

I used to, but that doesn't work anymore with modern led bulbs that
you can change the color temp of to anything you like remotely.

Why not?

Because the lumens change dramatically with the color temp.
http://www2.meethue.com/en-au/produc...specifications

100W equivalent is easy to understand.

Not when the color temp changes.

I don't tend to buy adjustable ones.

I prefer to be able to vary that, because I
don't use the same color temp all the time.

"100W equivalent" still makes sense.

At least most LEDs are 10x as efficient, so you can just multiply by 10.

I buy ones with the temp I want, which is daylight white.

The previous lights were a combination of 4' fluoros and
PAR38 floods. I prefer different color temps in some
situations most obviously when doing fine repair work
and when watching recorded video or reading a book etc.

Are you sure you're not female? They like different colours according to mood.

--
There are forty £100 million notes in the Bank of England.

On Wed, 17 May 2017 23:46:07 +0100, Rod Speed wrote:



"James Wilkinson Sword" wrote in message
news
On Wed, 26 Apr 2017 22:08:33 +0100, Rod Speed
wrote:

James Wilkinson Sword wrote
Rod Speed wrote
James Wilkinson Sword wrote

With a few junctions and a few phosphors, I can't see why we can't
make
a real sun spectrum.

Because the sun produces a quite uniform spectrum because of the way it
emits the light.

So?

So you'll never get even close with leds.

Put several LEDs in the package,

All that does if put more spikes in the spectrum.

then add phosphors to smooth things over.

Phosphors don't do that. They have their own spikes.

I'm not asking for identical, just something vaguely similar.

It isnt even vaguely similar spectrum wise.

Adequate for a domestic situation, but that's all.

The current ones are pretty close. Double the number of LEDs or phosphors
and the graph would look pretty good.

Nope.

Yes, the graphs already look quite even.

All we have is cool white and warm white.

Wrong, as always.

Apart from some specialised ones perhaps.

Nothing specialised about the ones where you can
control the color temp because they can do 16M colors.

They're not very common.

Irrelevant to whether they are specialised or not.

That's what specialised means.

Never even heard of them until you mentioned them.

Sure, they havent been around all that long yet.

Seems to take ages for things to get sold in shops. I was buying LED bulbs on Ebay about 10 years before Asda sold them.

But most LED bulbs only have two whites.

Most can in fact do full RGB.

Only a few like yours.

There are heaps of them than can do full RGB

Clearly not as I've never even seen one, yet there are warm/cool whites available everywhere.

--
Question: Are there too many immigrants in Britain?
17% said yes, 11% said no, 72% said "I am not understanding the question please."

"James Wilkinson Sword" wrote in message
news
On Wed, 17 May 2017 23:43:03 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news
On Wed, 26 Apr 2017 01:04:04 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 23:56:44 +0100, Rod Speed

wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 23:04:08 +0100, Rod Speed

wrote:



"James Wilkinson Sword" wrote in message
news On Tue, 25 Apr 2017 22:12:37 +0100, Johnny B Good
wrote:

On Tue, 25 Apr 2017 14:27:29 +0100, Martin Brown wrote:

On 25/04/2017 13:27, Graham. wrote:
On Tue, 25 Apr 2017 12:25:35 +0100, "James Wilkinson Sword"
wrote:

Yes, I've googled it, but there are many different approaches.
Which
one is used in domestic LED bulbs?

Ultra-violet LED exciting a white phosphor, much the same
principle
used in florescents.

It is usually a high efficiency blue LED pump exciting a yellow
phosphor
with that mix determining the nominal colour temperature. It is
quite
peaky in the blue and more of a wide hump around the yellow. The
phosphor usually looks yellow and sits on top of the LED.

http://i.stack.imgur.com/lkyXG.png

The visible light flux out of an LED die on a high efficiency
LED
these
days is about the same order of magnitude as the sun's
photosphere.

It is a lot more obvious on the devices which use a remote
phosphor.

http://www.cree.com/led-components/m...e-Phosphor.pdf

An interesting read (note the use of the expression "loosing
efficiency"
on page 8 regarding Fig 7a). Also of note is the copyright date
of
this
document which is the year of their record breaking 303Lm/W led
efficacy
achievement in February/March of that year when the Cree
Spokesperson
let
slip to the trade press that such laboratory achievements
typically
took
a further 18 to 24 months of development before making their
début
on
store shelves for public consumption.

A simple arithmetic calculation reveals that this scheduled
development
has slipped by a rather conservatively estimated 13 months. :-(
The
best
Lm/W efficacy figures I've noted recently have been around the
125
to
145
Lm/W mark. The former being a 1500Lm 12W GLS B22 2700K Warm White
lamp
I
sampled from a Home Bargains store for the princely sum of £2.99
which
turned out to have an *actual* consumption figure of 14 watts.

I thought the best LEDs were equivalent to 10W out per 1W in. Eg
a
10W
LED bulb should be equivalent to a 100W incandescent. A 100W
incandescent
is 1435 lumens. So your bulb is consuming 14W to give out about
105W.
Not as good as I thought.

Since its illumination power doesn't seem as impressively bright
as
I
was expecting (even making allowances for the eye's logarithmic
response
to brightness), I rather doubt the additional 2 watts is hiking
the
claimed 1500Lm to 1750Lms as one might expect if the additional 2
watts
was simply the result of overly wide tolerances in the
'electronic
ballast circuit' causing the LEDs to be overdriven to a higher
than
designed Lumens output.

I have a sneaking suspicion that the claims of "1500 Lumens at
12W
(100W
eqv)" have been based on the best of a sampling of these lamps
off
the
production line, possibly based on the maximum positive tolerance
limit
of the 'nominal' power consumption to boot for good measure
(+10%?
=
13.2W) so might more typically be nearer the 110Lm/W mark than to
the
claimed 125Lm/W figure. Even the claimed efficacy is not a
particularly
massive improvement over the 81Lm/W efficacy figures typical of
many
LED
GLS lamps of just over three years ago.

Companies lie, they always do. Cameras state x MP, and if you
take
a
photo at full resolution, it's ****. Hard disks don't use
gigabytes,
but
billions of bytes, shaving off a little.

The 145Lm/W lamps I saw were the grossly overpriced 1600Lm LES
11W
examples being offered by Asda. I might have considered buying
one
if
they'd been more sanely priced but at something like 10 to 18
quid
a
pop
(I didn't bother trying to pin the confusing shelf price
labelling
down
any tighter than that - it was enough to know that it was at
least
3
times pricier than I'd been prepared to pay in Home and Bargain),
I
wasn't in the least bit tempted.

I'm currently using this sort of thing:
http://www.ebay.co.uk/itm/231644564446

I want complete remote control of on/off, color temp and dimming,
by
voice.

I don't see the need for that.

I do, I don't want the same light level all the time that its useful
to
have
the light on.

I prefer a brighter light on what I am eating than when I am typing
after
eating and a different light level when watching recorded videos
etc.

Odd, I just like it bright all the time so I can see what I'm doing.

I do want to do that when eating or repairing stuff,
but not when using the computer or watching videos.

Why not?

Works better to have the screen the brightest in that situation,
its not washed out by the maximum brightness room lighting.

Nope,

Yep.

it's the same brightness as the rest of the room,

That's ****ed.

much more comfortable to look at.

Only for those with ****ed eyes that are so slow to
compensate for changing light levels that they can't
even handle cars with their headlights on during the day.

I make the TV/monitor bright enough to see in that amount of ambient
light. The exception is my bedroom where I have a dimmer light so I
don't wake up and get dazzled.

Yeah, tho I prefer a soft start there, but want full
brightness so I can read the non backlit scales better.

I should get some automatically recording scales
but currently havent found any that are even that
reproducible so they read the same thing if you
weigh yourself say 5 times in a row. Had a hell
of a job finding a decent set of digital scales
that don't have any recording capability at all.

I don't have scales in the bedroom, don't they normally live in the
bathroom?

I don't give a flying red **** what is normal,
I do what works best for me.

You could stop being such a cheapskate and get backlit scales.

Stupid approach, you need to fart around changing the battery
much more often with those. Makes a lot more sense to have a
mains powered cheap sensor led light for it or go even further
and have it auto load the weight into your phone so you don't
even have to read the scales at all.

Anyway why are you so obsessed with your weight?

I'm not. But it's the reason I am within the best BMI range and you
arent, lard arse.

Life is way more comfortable if you eat what your body wants you to.

Even sillier than you usually manage. Lard arses
like you can't even put your sox and shoes on easily
and waddle around all the time and end up very
uncomfortable indeed with ****ed knees and
sores that wont heal due to their diabetes.

You have a natural BMI according to your genetics,

Even sillier than you usually manage. We evolved with
very low calorie food, lots of exercise and now end up
morbidly obese like you with modern high calorie food.

if you try to change it you're constantly depriving yourself of food.

I do nothing of the sort, lard arse.

Sure, but when you have one already, you know if that amount of
lumens is enough there or not.

I think in watts. I know what a 100W lightbulb is like.

I used to, but that doesn't work anymore with modern led bulbs that
you can change the color temp of to anything you like remotely.

Why not?

Because the lumens change dramatically with the color temp.
http://www2.meethue.com/en-au/produc...specifications

100W equivalent is easy to understand.

Not when the color temp changes.

I don't tend to buy adjustable ones.

I prefer to be able to vary that, because I
don't use the same color temp all the time.

"100W equivalent" still makes sense.

Nope, because there is no such thing. There is
a world of a difference between a normal 100W
incandescent bulb in a normal light fitting and
a 100W reflector bulb in a downlight.

At least most LEDs are 10x as efficient, so you can just multiply by 10.

Even sillier than you usually manage as the lumens/watt changes.

I buy ones with the temp I want, which is daylight white.

The previous lights were a combination of 4' fluoros and PAR38 floods. I
prefer different color temps in some
situations most obviously when doing fine repair work
and when watching recorded video or reading a book etc.

Are you sure you're not female? They like different colours according to
mood.

I'm not talking about mood, I'm taking about what I am doing.

"James Wilkinson Sword" wrote in message
news
On Wed, 17 May 2017 23:46:07 +0100, Rod Speed
wrote:



"James Wilkinson Sword" wrote in message
news
On Wed, 26 Apr 2017 22:08:33 +0100, Rod Speed
wrote:

James Wilkinson Sword wrote
Rod Speed wrote
James Wilkinson Sword wrote

With a few junctions and a few phosphors, I can't see why we can't
make
a real sun spectrum.

Because the sun produces a quite uniform spectrum because of the way
it
emits the light.

So?

So you'll never get even close with leds.

Put several LEDs in the package,

All that does if put more spikes in the spectrum.

then add phosphors to smooth things over.

Phosphors don't do that. They have their own spikes.

I'm not asking for identical, just something vaguely similar.

It isnt even vaguely similar spectrum wise.

Adequate for a domestic situation, but that's all.

The current ones are pretty close. Double the number of LEDs or
phosphors and the graph would look pretty good.

Nope.

Yes, the graphs already look quite even.

Like hell they do.

All we have is cool white and warm white.

Wrong, as always.

Apart from some specialised ones perhaps.

Nothing specialised about the ones where you can
control the color temp because they can do 16M colors.

They're not very common.

Irrelevant to whether they are specialised or not.

That's what specialised means.

Nope.

Never even heard of them until you mentioned them.

Sure, they havent been around all that long yet.

Seems to take ages for things to get sold in shops.

Yep.

I was buying LED bulbs on Ebay about 10 years before Asda sold them.

Because hardly anyone wanted to buy them at that
price or the stupidly low quality **** from china.

But most LED bulbs only have two whites.

Most can in fact do full RGB.

Only a few like yours.

There are heaps of them than can do full RGB

Clearly not as I've never even seen one,

That's because you have wanked yourself completely
blind. You were warned, you wouldn't listen...

yet there are warm/cool whites available everywhere.