On 09/06/2021 18:05, T i m wrote:

The shame is (often old) people paying to have their new DTV 'set up'
when in many cases you just plug it in and follow the onscreen prompts
and it does it all for you (unlike the old ATV where you had to
manually tune each button and the video etc). ;-)

Or they try to install it themselves, it mis-tunes to the wrong tx, so
they assume they need a 'digital aerial' and some **** in my trade comes
along, rips them for £150, then tunes the TV correctly.

Bill

On 09/06/2021 18:41, Fredxx wrote:
On 09/06/2021 17:23, williamwright wrote:
On 09/06/2021 13:15, Andrew wrote:
And fluorescent tubes are reasonably efficient in terms of
light output vs power in.

They are the same as LEDS

Generally they're twice as efficient as fluorescent tubes. As this link
demonstrates:
Â* https://en.wikipedia.org/wiki/Luminous_efficacy

Generally? Only one type. I know that when I've swapped fluos for LEDs
the latter haven't seemed much brighter, if at all.

Bill

"T i m" wrote in message
...
On Wed, 9 Jun 2021 16:07:42 +0100, "tim..."
wrote:

snip

I put the CFL back in

5W LED is just too damned bright to be turning on whilst you are sleepy

The fact that CFL often take a few seconds yo 'warm up' helps with
that.

makes of LED bulbs really ought to think about this

Some of the LED lamps that come on and off automatically as driven
from my Home Assistant system seem to 'ramp the on brightness'
slightly (quickly) and much more visually down when turning off

Its trivially programmable to any rate you like with the Philips Hue system.

(compared when turning them off at the wall) so that change in
functionality is probably because they are being used 'smart'?

When they are off at the wall they are completely off (electrically)
of course whereas when off from Home Assistant they are still
powered but are set to zero light output.

If you set them to come on via a remote of some sort you can
gave them come on at whatever level is appropriate (and that
could vary depending on the time of day) but still be turned
up or down as required (same remote).

And by light level too.

On 09/06/2021 22:51, T i m wrote:
On Wed, 9 Jun 2021 15:24:17 +0100, Mark Carver
wrote:

snip

I doubt LEDs will work in our John Lewis 'touch sensitive/three level'
bedside lamps.
FWIW I put a dimmable LED lamp in mums 'touch sensitive three level'
table lamp (and two similar used as bedside lights) and it/they worked
fine? I can't imagine it was bought with LED compatibility in mind but
it could have been LED compatible of course.

Interesting. I'll get an LED replacement bulb, and give it a spin then.
They might have been bought from Homebase FWIW.


I'm sure the 'guts' all come from the same place in China !

On Thu, 10 Jun 2021 14:16:56 +1000, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:


Its trivially programmable to any rate you like with the Philips Hue system.

Shove your idiotic Philips Hue up your senile arse, senile asshole! tsk

On Thu, 10 Jun 2021 02:05:05 +0100, williamwright
wrote:

On 09/06/2021 18:05, T i m wrote:

The shame is (often old) people paying to have their new DTV 'set up'
when in many cases you just plug it in and follow the onscreen prompts
and it does it all for you (unlike the old ATV where you had to
manually tune each button and the video etc). ;-)

Or they try to install it themselves, it mis-tunes to the wrong tx,

(How often / easy is that to happen and under what circumstances would
you say? I mean, don't the TV's often ask for your location / 'Region
to (presumably) know what range of frequencies it should be looking
for?)

so
they assume they need a 'digital aerial'

;-)

and some **** in my trade comes
along, rips them for £150, then tunes the TV correctly.

;-(

If 'automatic' tuning doesn't work because it can be confused by which
transmitter(s?) to use, would that mean tuning it manually and what
typically happens after when a re-tune is required?

Asking because we live in an area that is only really served by one TX
so never had to manually tune a DTV.

Cheers, T i m

On Thu, 10 Jun 2021 00:29:18 +0100, D i m, the absolutely brain dead
notorious troll-feeding senile asshole, blathered, yet again:


Cheers, D i m

You'll thankfully keep feeding ANY filthy, vicious troll that comes along,
eh, senile D i m? Just how miserable are all you senile assholes that are
slowly taking over Usenet? G

"T i m" wrote in message
...
(How often / easy is that to happen and under what circumstances would
you say? I mean, don't the TV's often ask for your location / 'Region
to (presumably) know what range of frequencies it should be looking
for?)

If 'automatic' tuning doesn't work because it can be confused by which
transmitter(s?) to use, would that mean tuning it manually and what
typically happens after when a re-tune is required?

I imagine it depends on TV firmware as to whether the TV asks for a postcode
to tune to the muxes on transmitter that is designated for that postcode, or
whether it just does a scan from UHF 21 to UHF 68 to see what it can find.
Usually you end up with all the muxes from the *same* transmitter, but I
have seen cases when you get a mixtu before the aerial at my parents'
holiday cottage was upgraded (presumably from grouped to wideband), there
were problems that an auto scan would pick up some muxes from Bilsdale (the
"correct" transmitter for that locality) and some muxes from Emley Moor
(which is miles away over several hills). Until we had the aerial changed
and a kink in the cable that fed the aerial wall-box repaired, I had to
manually tune each mux to prevent it finding Emley. I presume, because of
the old aerial's selective gain in different parts of the UHF spectrum, some
Emley muxes were actually stronger than some Bilsdale ones. There is also
the issue of atmospheric "lift" causing distant signals to be stronger at
certain times, which is a problem if you retune at that time.

In article ,
williamwright wrote:
On 09/06/2021 16:36, Dave Plowman (News) wrote:

I sort of assumed with a 1 metre dish it would be pretty tolerant. Find
any one of the Astra group and the others would be OK. But not so -
obviously.


If you look at the full spectrum at 28E on an analyser and gently pull
at the rim of the dish you can see some signals strengthen whilst others
weaken.

Bill

Right. I'd guess a spectrum analyser would be a bit of a luxury for me,
though. ;-)

I did quite a bit of Googling on setting up a motorised dish. Most of the
Utube stuff just confused me, as I simply wanted an idiots guide.

So here's mine:-

Make sure the mounting pole is truly vertical. That could be tricky
working off a ladder.

Set the motor to 0. Mount the disc making sure it is pointing straight
ahead, relative to that 0. Some dishes may not have a big enough flat on
the back to use a set square, so measure from each side of the dish to the
motor centre. Make sure the dish mounting is the correct distance up the
motor mounting tube.

Set the elevation on the motor adjustment, using the motor maker's data.
And then the disc bracket angle.

Now rotate the motor mounting to point due south. I found a phone app
better than a compass.

My receiver then found all the satellites in its list - with the exception
of a couple to the west where my dish is looking through a thick large
chestnut tree.

--
*Don't squat with your spurs on *

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

In article ,
NY wrote:
I imagine it depends on TV firmware as to whether the TV asks for a
postcode to tune to the muxes on transmitter that is designated for
that postcode, or whether it just does a scan from UHF 21 to UHF 68 to
see what it can find.

Pretty well every TV I've seen in the last many years asks for your
country and town, etc, before tuning.

Of course if you live in a remote area, you may have a choice of
transmitters. and may want to choose the one which gives you all the progs
you want.

--
*You can't teach an old mouse new clicks *

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

In article ,
Fredxx wrote:
On 10/06/2021 00:18, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
When I looked into this, the issue was with cars and not bikes. You
can fit LEDs to cars if there is some self-levelling of headlamp aim
and headlamp wash-wipes. Those rules don't apply to bikes.

I also read that these rules only apply to lamps above a certain
light output.

That could make more sense. But I think you're wrong. That is the
problem with headlight regs. They don't mention light output.

I tried looking up the claim and have come to the conclusion I must have
dreamt it. From:

https://www.autobulbsdirect.co.uk/bl...gal-in-the-uk/

Please note that since January 2021, the MOT Inspection manual has been
updated to include LED bulbs.

Section 4.1.4 now states the following:

”Existing halogen headlamp units should not be converted to be used with
high intensity discharge (HID) or light emitting diode (LED) bulbs. If
such a conversion has been done, you must fail the headlamp.•

This is a brand new update that seems to only focus on headlights.

Yes, and it's typical broad nonsense. It depends on the design of your
headlamp unit if a different light source gives a decently controlled beam.

I did some tests on mine, which has projector headlights (the type with a
bulls eye in front of the bulb) Have a convenient car park with a white
wall, so you can see the beam pattern easily. It was identical with the
original halogen, HID, and LED. This type of headlight gives a very sharp
cutoff due to using a french flag to shape it. (It also allows an easy
change from RHD to LHD by simply changing the flag - some do this with a
lever)

Non projector units will likely produce a lot of scatter when you change
the light source, as the size and position of this varies with type of
bulb, so will be out of focus.

There are no mentions to fail other LED bulbs such as brake lights, tail
lights or reversing lights."

But there will still be idiots who change their colour. ;-)

--
*When a clock is hungry it goes back four seconds*

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

On 10/06/2021 02:14, williamwright wrote:
On 09/06/2021 18:41, Fredxx wrote:
On 09/06/2021 17:23, williamwright wrote:
On 09/06/2021 13:15, Andrew wrote:
And fluorescent tubes are reasonably efficient in terms of
light output vs power in.

They are the same as LEDS

Generally they're twice as efficient as fluorescent tubes. As this
link demonstrates:
Â*Â* https://en.wikipedia.org/wiki/Luminous_efficacy

Generally? Only one type. I know that when I've swapped fluos for LEDs
the latter haven't seemed much brighter, if at all.

I would have thought the wiki article be a general comparison, BICBW.

I have a direct comparison between some ageing fluorescent tubes and
their LED counterparts.

I recently replaced some Sylvania 6ft T5 tubes rated at 70W.

I bought some Energiser replacements and these are cool white rated at 30W.

Because of access issues I still have the original florries in some places.

It means I can make side by side comparison. The LED tubes provide a
natural white, where the florries have a magenta tinge, lacking green in
comparison. Others have also commented that the LED tubes are brighter.

You also have to take the ballast into consideration but given the
temperature this runs at I guess the loss is 5-10W, possibly more. I
shorted the ballasts when fitting the LED tubes.

This is a place where there are 19 tubes, so the power saving is
significant. After a year none has failed. These are branded tubes as I
was wary about getting no-name ones.

That is my experience, I fully accept YMMV.

"Fredxx" wrote in message
...
It means I can make side by side comparison. The LED tubes provide a
natural white, where the florries have a magenta tinge, lacking green in
comparison. Others have also commented that the LED tubes are brighter.

Interesting. To my eye, "daylight" CFLs have a very faint greenish tint,
like looking through thick glass. And florrie tubes always used to reproduce
on daylight slide film with a strong green cast: you used to be able to buy
a pale magenta filter to compensate for it (*). So it is interesting that
your florries look to have too *little* rather than too *much* green. Shows
how unreliable film and the eyes are when faced with a discontinuous
spectrum!


(*) I wonder if the same filter worked for all films or whether some brands
had different spectral sensitivities to others. And of course you'd need a
different filter for each type (warm/cool-white) of tube.

On 10/06/2021 13:15, NY wrote:
"Fredxx" wrote in message
...
It means I can make side by side comparison. The LED tubes provide a
natural white, where the florries have a magenta tinge, lacking green
in comparison. Others have also commented that the LED tubes are
brighter.

Interesting. To my eye, "daylight" CFLs have a very faint greenish tint,
like looking through thick glass. And florrie tubes always used to
reproduce on daylight slide film with a strong green cast: you used to
be able to buy a pale magenta filter to compensate for it (*). So it is
interesting that your florries look to have too *little* rather than too
*much* green. Shows how unreliable film and the eyes are when faced with
a discontinuous spectrum!


Its fredxx he cant rell his arse from his elbow. It is well known that
fluoros have an overall green cast.



(*) I wonder if the same filter worked for all films or whether some
brands had different spectral sensitivities to others. And of course
you'd need a different filter for each type (warm/cool-white) of tube.

It worked for all films more or less. No two film types were the same.
Konica print was the film of choice for portrait as it rendered flesh
tones brilliantly. Fuji did nice greens. As did Agfa. Kodak was horrible
- glaring bright colors - ok for arty shots, but nowhere near natural
Kodachrome however, especially 25, was a beautiful - and extremely
expensive - film

Age also makes a difference. I took two bodies on holiday to the Med
once, and found one had film in it from ten years before. I shot it, but
it came with a massive green cast. Digitised the negs and played around
with Gimp and got very acceptable final results

I think that was the last time I used a film camera

--
"And if the blind lead the blind, both shall fall into the ditch".

Gospel of St. Mathew 15:14

On 10/06/2021 13:27, The Natural Philosopher wrote:
On 10/06/2021 13:15, NY wrote:
"Fredxx" wrote in message
...
It means I can make side by side comparison. The LED tubes provide a
natural white, where the florries have a magenta tinge, lacking green
in comparison. Others have also commented that the LED tubes are
brighter.

Interesting. To my eye, "daylight" CFLs have a very faint greenish
tint, like looking through thick glass. And florrie tubes always used
to reproduce on daylight slide film with a strong green cast: you used
to be able to buy a pale magenta filter to compensate for it (*). So
it is interesting that your florries look to have too *little* rather
than too *much* green. Shows how unreliable film and the eyes are when
faced with a discontinuous spectrum!


Its fredxx he cant rell his arse from his elbow.

Stop judging others by your own failings.

It is well known that
fluoros have an overall green cast.

It may be well known to you, but you don't have the two lamps near side
by side to make a comparison.

On Thu, 10 Jun 2021 07:48:45 +0100, Mark Carver
wrote:

On 09/06/2021 22:51, T i m wrote:
On Wed, 9 Jun 2021 15:24:17 +0100, Mark Carver
wrote:

snip

I doubt LEDs will work in our John Lewis 'touch sensitive/three level'
bedside lamps.
FWIW I put a dimmable LED lamp in mums 'touch sensitive three level'
table lamp (and two similar used as bedside lights) and it/they worked
fine? I can't imagine it was bought with LED compatibility in mind but
it could have been LED compatible of course.

Interesting. I'll get an LED replacement bulb, and give it a spin then.
They might have been bought from Homebase FWIW.


I'm sure the 'guts' all come from the same place in China !

You are probably right, even if they were initially designed here.

Cheers, T i m

In article ,
Fredxx wrote:
It means I can make side by side comparison. The LED tubes provide a
natural white, where the florries have a magenta tinge, lacking green in
comparison. Others have also commented that the LED tubes are brighter.

You do realise there is a vast range of florry tubes available? ie, not
just white and warm white? Of course, as with most things, decent tubes
are more expensive than the ones which come with the fittings.

There are tri-phosphor tubes on the market that are suitable for
photography etc where light quality is important.

--
*Rehab is for quitters.

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

In article ,
Tim Streater wrote:
On 10 Jun 2021 at 13:27:54 BST, The Natural Philosopher
wrote:

Kodachrome however, especially 25, was a beautiful - and extremely
expensive - film

Agree it was beautiful, wouldn't agree it was particularly expensive. I
never used anything else and regret its passing.

Try photographing red blue and green gels with your favourite film. Then
make up a slide, half the developed film, and half the original gels, and
project it onto a screen. Then tell us how wonderful colour film is. ;-)

--
*Keep honking...I'm reloading.

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

On 10/06/2021 15:17, Tim Streater wrote:
On 10 Jun 2021 at 13:27:54 BST, The Natural Philosopher
wrote:

Kodachrome however, especially 25, was a beautiful - and extremely
expensive - film

Agree it was beautiful, wouldn't agree it was particularly expensive. I never
used anything else and regret its passing.


It was the same price as Kodachrome 64 and Kodachrome 200 in 35mm format
from what I remember.

On 10/06/2021 16:59, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
It means I can make side by side comparison. The LED tubes provide a
natural white, where the florries have a magenta tinge, lacking green in
comparison. Others have also commented that the LED tubes are brighter.

You do realise there is a vast range of florry tubes available? ie, not
just white and warm white? Of course, as with most things, decent tubes
are more expensive than the ones which come with the fittings.

I am very aware of that, this sub-thread was about efficiency rather
than colour after Bill's comment. My post about colour was intending to
be a throw away comment when making the comparison.

The old tubes were marked Sylvania, hardly a no-name brand.

One thing I didn't mention is that LED tube replacements claim a 270
degree output as opposed to the original at close to 360, hence this
could account for some increase in output when viewing the lamp directly.

There are tri-phosphor tubes on the market that are suitable for
photography etc where light quality is important.

I think you have said this before. I suspect they're expensive? Don't
they also degrade over time?

On 10/06/2021 09:35, T i m wrote:

Or they try to install it themselves, it mis-tunes to the wrong tx,

(How often / easy is that to happen and under what circumstances would
you say? I mean, don't the TV's often ask for your location / 'Region

TV reception being what it is, the strongest signal might be the wrong
signal.


If 'automatic' tuning doesn't work because it can be confused by which
transmitter(s?) to use, would that mean tuning it manually and what
typically happens after when a re-tune is required?

They get a grandchild to do it.

Bill

On 10/06/2021 11:47, Dave Plowman (News) wrote:
Of course if you live in a remote area, you may have a choice of
transmitters.

A remote area like South Yorkshire, with Crosspool, Emley, Bilsdale,
Waltham and Belmont all competing for the TV set's attention!

Bill

On 10/06/2021 13:27, The Natural Philosopher wrote:
Age also makes a difference. I took two bodies on holiday to the Med once,

My mind is wondering again.

Bill

In article ,
williamwright wrote:
On 10/06/2021 09:35, T i m wrote:

Or they try to install it themselves, it mis-tunes to the wrong tx,

(How often / easy is that to happen and under what circumstances would
you say? I mean, don't the TV's often ask for your location / 'Region

TV reception being what it is, the strongest signal might be the wrong
signal.

Is that still the case with digital?


If 'automatic' tuning doesn't work because it can be confused by which
transmitter(s?) to use, would that mean tuning it manually and what
typically happens after when a re-tune is required?

They get a grandchild to do it.

Bill

--
*Sorry, I don't date outside my species.

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

In article ,
Fredxx wrote:
On 10/06/2021 16:59, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
It means I can make side by side comparison. The LED tubes provide a
natural white, where the florries have a magenta tinge, lacking green
in comparison. Others have also commented that the LED tubes are
brighter.

You do realise there is a vast range of florry tubes available? ie,
not just white and warm white? Of course, as with most things, decent
tubes are more expensive than the ones which come with the fittings.

I am very aware of that, this sub-thread was about efficiency rather
than colour after Bill's comment. My post about colour was intending to
be a throw away comment when making the comparison.

The old tubes were marked Sylvania, hardly a no-name brand.

The same tube maker often does all the varieties. Cooking white may give
you the best lumens per watt, but that says nothing about the light
quality. Of course perhaps most don't care.

One thing I didn't mention is that LED tube replacements claim a 270
degree output as opposed to the original at close to 360, hence this
could account for some increase in output when viewing the lamp directly.

You tend to get the same with LED GLS bulbs. They appear as bright as
their claimed tungsten equivalent, but may well be different when
reflected light off ceilings etc is taken into account.

There are tri-phosphor tubes on the market that are suitable for
photography etc where light quality is important.

I think you have said this before. I suspect they're expensive? Don't
they also degrade over time?

Given they have a very long life, a drop in the ocean. BTW, I've found
hard driven LEDs deteriorate too. Not sure if this applies to domestic
ones.

--
*If God dropped acid, would he see people?

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

On 10/06/2021 15:09, Fredxx wrote:

It is well known that fluoros have an overall green cast.

It may be well known to you, but you don't have the two lamps near side
by side to make a comparison.

I think maybe the belief that fluos have a green cast comes from the was
film and sensors respond to their spectrum.

Bill

On 10/06/2021 15:17, Tim Streater wrote:
On 10 Jun 2021 at 13:27:54 BST, The Natural Philosopher
wrote:

Kodachrome however, especially 25, was a beautiful - and extremely
expensive - film

Agree it was beautiful, wouldn't agree it was particularly expensive. I never
used anything else and regret its passing.


I thought it was the same price as Kodachrome 64.

Bill

On 10/06/2021 18:36, Dave Plowman (News) wrote:

TV reception being what it is, the strongest signal might be the wrong
signal.

Is that still the case with digital?

Yes. It might be the wrong region. For example
1. Most of N Yorks gets a stronger Bilsdale than Emley but Emley is the
correct region.
2. Some areas of Sheffield get monster signals from Crosspool but they
are unreliable due to tree screening, so people tend to use Belmont.
3. Some coastal areas are affected by tidal fading so people tend to use
a weaker signal from an inland tx.

Bill

On 10/06/2021 18:45, williamwright wrote:
On 10/06/2021 15:09, Fredxx wrote:

It is well known that fluoros have an overall green cast.

It may be well known to you, but you don't have the two lamps near
side by side to make a comparison.

I think maybe the belief that fluos have a green cast comes from the was
film and sensors respond to their spectrum.

I'm sure the eye response is very different to film emulsion response. I
am aware the emission from a tri-phosphor tube is not flat:
http://www.lamptech.co.uk/Documents/FL%20Phosphors.htm

On Thu, 10 Jun 2021 17:37:32 +0100, williamwright
wrote:

On 10/06/2021 09:35, T i m wrote:

Or they try to install it themselves, it mis-tunes to the wrong tx,

(How often / easy is that to happen and under what circumstances would
you say? I mean, don't the TV's often ask for your location / 'Region

TV reception being what it is, the strongest signal might be the wrong
signal.

Noted.


If 'automatic' tuning doesn't work because it can be confused by which
transmitter(s?) to use, would that mean tuning it manually and what
typically happens after when a re-tune is required?

They get a grandchild to do it.

;-)

Or often along this row of cottages, yours truly. ;-)

That said, I think I've probably had to re-enable more things that
they disabled because of finger trouble on digital systems than I have
tuning or re-tuning analogue stuff.

Tell me if this sounds familiar ...

Ding dong ... Hello yourname, I'm sorry to trouble you again but I
think I have broken something on my TV as I was just going to watch
what I recorded yesterday and I pressed something and now it's all
gone black but would you be able to come along soon and look at it for
me and tell me if I need to replace something we are now walking
along to hers ... as Cynthia and Joan are coming along at 2 and we
are going shopping but I wanted to watch it before they come round as
they will want to talk about it and we won't be able if I haven't
watched it yet going into their place ... thanks for coming along
and I'm sorry to bother you again but I phoned Darren and he said he
can come round this evening and look at it for me but oh ... you've
got it working ... thank you so much, what would I do without you ...
can I give you some cake ... ;-)

Cheers, T i m

"Andrew" wrote in message
...
On 10/06/2021 15:17, Tim Streater wrote:
On 10 Jun 2021 at 13:27:54 BST, The Natural Philosopher

wrote:

Kodachrome however, especially 25, was a beautiful - and extremely
expensive - film

Agree it was beautiful, wouldn't agree it was particularly expensive. I
never
used anything else and regret its passing.


It was the same price as Kodachrome 64 and Kodachrome 200 in 35mm format
from what I remember.

Kodachrome 200? That must have been after I stopped using film and went over
to digital. The fastest I can remember is Kodachrome 64 - and that was
pretty slow for interior shots. What speed was Kodachrome Super 8 cine film?
I think it might have been 16, to get the finest grain possible - hence the
need for powerful photoflood lights indoors ;-)

I found that Kodachrome was good for fidelity of colours, but was rather
contrasty: you lost a bit of highlight and shadow detail, and the shadows
were ever so slightly greenish. Ektachrome was better for this and was of
course a lot faster (160 [tungsten], 200 or 400), but it had a slightly
colder colour balance. I once push-processed Ektachrome 160 to 640 ASA
(underexpose by two stops, get the lab to overdevelop by two stops) for some
photos I was taking of my sister taking part in a gymnastics contest indoors
under stage lighting. The results were not pretty: very contrasty and
over-saturated colours. Nowadays I could use a digital camera at 3200 ASA in
any colour of "white" light ranging from tungsten bulbs (2400K) up to
outdoor shade (about 10000K) and get equally good results. You have to look
pretty hard to distinguish 100 ASA from 3200 ASA with my DSLR.


One thing I discovered when I came to scan my dad's slides and mine with a
scanner that uses IR to detect dust and correct for it, is that this does
not work with Kodachrome: there is something in the emulsion which
attenuates IR to a variable extent depending on slide density, whereas I
presume IR dust correction assumes that film of any visible density
attenuates IR equally. This means that Kodachrome slides scanned with
dust-removal turned on have a strange tonal quality and slight blurring
which varies with brightness - yuk! That was certainly the case for my
Minolta film scanner and AFAIK is the case with all scanners which use IR to
detect dust. Ektachrome, AgfaChrome and OEM films (eg Boots' slide film),
and all colour negative films, work fine with dust-removal turned on.
However I never cracked the problem of how to get faithful-looking scans of
colour negs: the colours always looked a bit "artificial" and OTT, rather
like the illustration on colour "plates" in a book from the 1930s-50s.

"williamwright" wrote in message
...
On 10/06/2021 15:09, Fredxx wrote:

It is well known that fluoros have an overall green cast.

It may be well known to you, but you don't have the two lamps near side
by side to make a comparison.

I think maybe the belief that fluos have a green cast comes from the was
film and sensors respond to their spectrum.

It is certainly a lot more exaggerated on colour slide film (especially
Kodachrome) than to the naked eye. Colour negative film is affected too, but
most print labs correct for colour cast. I remember taking two photos on
colour neg, one by fluorescent light and one by tungsten light, without any
colour-correction filters. Apart from differences in the shadows and
reflections off shiny objects, the two prints were pretty much
indistinguishable, even though there was a big difference in the negatives.

I've not seen the green cast with fluorescent lights with a digital camera.
Depending on what colour temperature preset you use, you get either an
orange cast or a blue cast (or no discernable cast), but never a green one.
So there's something about digital sensors which means they don't suffer
from it to the same extent - or else if it present at the sensor, it is
automatically corrected by the sensor-processing. That is true of "raw" DNG
files, as well as JPG which may have some normalisations.

In message , ARW
writes
On 09/06/2021 19:05, Tim Lamb wrote:
In message , Robin
writes
On 09/06/2021 14:06, Tim Lamb wrote:
In message ,
nightjar writes
On 09/06/2021 09:39, ss wrote:
..."Sales of halogen lightbulbs are to be banned in the UK from
September, with fluorescent lights to follow, under government
climate change plans"....

Apart from a few, rarely used, lamps that have yet to be changed,
I have long converted everything to LED.
*Hmm.. I have about 25 twin 5' florries in my workshop in 4
switched banks. This may be the moment to do the LED conversion.



You have plenty of time to find 50 round tuits given they'll be
phased out "from Sept 2023 onwards"
Huh! Put up with an access tower on bare floor. Place is half full
of fixed machinery now.
Might be doable with an agile bloke from Doncaster:-)



How high?

The barn ridge is around 20'. The florries are hung from chains attached
to the purlins so 18' and progressively lower.

These are weatherproof fittings (because I had some) and a pig to work
on from a ladder. Simplest taken down and replaced with a tested
modified unit.

A professional might have something embarassing to say about the
rewireable fuses in a 3 phase distribution board:-)




--
Tim Lamb

On 10/06/2021 21:21, NY wrote:
"williamwright" wrote in message
...
On 10/06/2021 15:09, Fredxx wrote:

It is well known that fluoros have an overall green cast.

It may be well known to you, but you don't have the two lamps near
side by side to make a comparison.

I think maybe the belief that fluos have a green cast comes from the
was film and sensors respond to their spectrum.

It is certainly a lot more exaggerated on colour slide film (especially
Kodachrome) than to the naked eye. Colour negative film is affected too,
but most print labs correct for colour cast. I remember taking two
photos on colour neg, one by fluorescent light and one by tungsten
light, without any colour-correction filters. Apart from differences in
the shadows and reflections off shiny objects, the two prints were
pretty much indistinguishable, even though there was a big difference in
the negatives.

I've not seen the green cast with fluorescent lights with a digital
camera. Depending on what colour temperature preset you use, you get
either an orange cast or a blue cast (or no discernable cast), but never
a green one. So there's something about digital sensors which means they
don't suffer from it to the same extent - or else if it present at the
sensor, it is automatically corrected by the sensor-processing. That is
true of "raw" DNG files, as well as JPG which may have some normalisations.

The colour pigments used in a Bayer filter are likely to be a better fit
to the eye sensitivity than a photographic emulsion. There are still
issues about sensitivity to near IR which is generally filtered
separately - off plane, usually within the lens.

On 10/06/2021 21:33, Tim Lamb wrote:
In message , ARW
writes
On 09/06/2021 19:05, Tim Lamb wrote:
In message , Robin
writes
On 09/06/2021 14:06, Tim Lamb wrote:
In message ,
nightjarÂ* writes
On 09/06/2021 09:39, ss wrote:
..."Sales of halogen lightbulbs are to be banned in the UK from
September, with fluorescent lights to follow, under government
climate change plans"....

Apart from a few, rarely used, lamps that have yet to be changed,
IÂ* have long converted everything to LED.
Â*Hmm.. I have about 25 twin 5' florries in my workshop in 4
switchedÂ* banks. This may be the moment to do the LED conversion.



You have plenty of time to find 50 round tuits given they'll be
phasedÂ* out "from Sept 2023 onwards"
Â*Huh! Put up with an access tower on bare floor. Place is half full
ofÂ* fixed machinery now.
Â*Might be doable with an agile bloke from Doncaster:-)



How high?

The barn ridge is around 20'. The florries are hung from chains attached
to the purlins so 18' and progressively lower.

These are weatherproof fittings (because I had some) and a pig to work
on from a ladder. Simplest taken down and replaced with a tested
modified unit.

A professional might have something embarassing to say aboutÂ* the
rewireable fuses in a 3 phase distribution board:-)





So gable end height on a newbild then.

There is noting wrong with fuses.

--
Adam

On Wed, 09 Jun 2021 16:35:31 +0100, "Dave Plowman (News)"
wrote:

snip

I've *just* picked up a high output 5' LED florry replacement for a
fitting in the study / workshop but the fitting is electronic so I'm
going to have to bypass all the 'guts'.

The main reason for doing it isn't (primarily) the light but the hope
it will get rid of the mains hum ... ;-(

Mains hum from an electronic ballast? Something not right there as they
(should) run at a higher frequency to get rid of flicker.

I just upgraded it and you were right, it wasn't HF (so at least that
makes more sense re the hum).

I took it down so I could see / access it better and it's just a std
LF job but with an unusual (to me anyway) 'built in' electronic
starter.

https://ibb.co/5WpjQm5

I pulled all the guts out because 1) I could and 2) it won't be going
back to florry / hum, 3) it was lighter to hold in place to re-attach
under the bed 4) I could re-wire it cleanly with all the crap out of
the way and 5) I could clean the fitting easier. ;-)

It's on it's side, under the built-in-bed and over the workbench so
the tube is 'facing' the back of the bench but as the underside of the
bed is white [1] and the LED tube supposed to illuminate 270 Deg, the
actual light (level and coverage) seems to be about the same as the
florry, maybe a touch brighter (it was a 'high output' one).

https://www.tlc-direct.co.uk/Products/LTTH527DL.html

I might see if I can fit a light deflector taking some of what is
currently going backwards and turning it down to the bench but only
after I've used it for real and done some fine soldering etc.

The good thing though, it seems to be as quiet as hoped (unlike one in
the kitchen that was also stripped of it's guts).

Cheers, T i m

[1] I wonder if some foil / chrome tape stuck under the bed above the
tube would reflect more light back than the white paint?

Fredxx wrote:
I'm sure the eye response is very different to film emulsion response.

Also, which may be relevant here - eye responses differ, sometimes
by quite a lot - between people.

#Paul

On 12/06/2021 14:12, #Paul wrote:
Fredxx wrote:
I'm sure the eye response is very different to film emulsion response.

Also, which may be relevant here - eye responses differ, sometimes
by quite a lot - between people.

They do indeed.

But the relevant blue, red, green cones in eyes have a similar response
in terms of wavelength.

Where the difference you mention comes from having different proportions
of these cones, or even one type missing.

In article ,
Fredxx wrote:
On 12/06/2021 14:12, #Paul wrote:
Fredxx wrote:
I'm sure the eye response is very different to film emulsion response.

Also, which may be relevant here - eye responses differ, sometimes
by quite a lot - between people.

They do indeed.

But the relevant blue, red, green cones in eyes have a similar response
in terms of wavelength.

Where the difference you mention comes from having different proportions
of these cones, or even one type missing.

It's interesting to view a narrow spectrum light - like say yellow low
pressure sodium - then match it by adjusting the RGB drives to a monitor.
No two people will get the same result.

--
*How much deeper would the oceans be without sponges? *

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

On 12/06/2021 18:14, Dave Plowman (News) wrote:
In article ,
Fredxx wrote:
On 12/06/2021 14:12, #Paul wrote:
Fredxx wrote:
I'm sure the eye response is very different to film emulsion response.

Also, which may be relevant here - eye responses differ, sometimes
by quite a lot - between people.

They do indeed.

But the relevant blue, red, green cones in eyes have a similar response
in terms of wavelength.

Where the difference you mention comes from having different proportions
of these cones, or even one type missing.

It's interesting to view a narrow spectrum light - like say yellow low
pressure sodium - then match it by adjusting the RGB drives to a monitor.
No two people will get the same result.

Is your experience is with CRT? These are associated with poor purity
wrt to LCD

http://www.marcelpatek.com/LCD.html

I would wager, if you have a 'pure' green LED light mixed with a 'pure'
red LED I suspect the difference would be somewhat less for the average
observer, except those who are truly missing a set of cones or someone
who cannot distinguish between red and green.

BICBW