It is a pity we are 'stuck' with relating brightness to wattage. If we used
a proper definitive measure of brightness then manufacturers would have to
be more honest.
Brightness is something that can be properly measured with a calibrated
instrument. Relating everything to a poor performing incandescent is not
good science.

(Lux - Candela - Lumens - whatever)

On Thu, 26 Nov 2009 14:58:02 -0000, "John"
wrote:

It is a pity we are 'stuck' with relating brightness to wattage. If we used
a proper definitive measure of brightness then manufacturers would have to
be more honest.
Brightness is something that can be properly measured with a calibrated
instrument. Relating everything to a poor performing incandescent is not
good science.

(Lux - Candela - Lumens - whatever)

Foot candles.

--
Frank Erskine

On Thu, 26 Nov 2009 15:23:34 +0000, Frank Erskine
wrote:

On Thu, 26 Nov 2009 14:58:02 -0000, "John"
wrote:

It is a pity we are 'stuck' with relating brightness to wattage. If we used
a proper definitive measure of brightness then manufacturers would have to
be more honest.
Brightness is something that can be properly measured with a calibrated
instrument. Relating everything to a poor performing incandescent is not
good science.

(Lux - Candela - Lumens - whatever)

Foot candles.

Foot Lamberts

On Thu, 26 Nov 2009 15:55:10 +0000, Derek Geldard
wrote:

On Thu, 26 Nov 2009 15:23:34 +0000, Frank Erskine
wrote:

On Thu, 26 Nov 2009 14:58:02 -0000, "John"
wrote:

It is a pity we are 'stuck' with relating brightness to wattage. If we used
a proper definitive measure of brightness then manufacturers would have to
be more honest.
Brightness is something that can be properly measured with a calibrated
instrument. Relating everything to a poor performing incandescent is not
good science.

(Lux - Candela - Lumens - whatever)

Foot candles.

Foot Lamberts

Apostilbs

On Thu, 26 Nov 2009 15:58:22 +0000, Derek Geldard
wrote:


On Thu, 26 Nov 2009 15:55:10 +0000, Derek Geldard
wrote:

On Thu, 26 Nov 2009 15:23:34 +0000, Frank Erskine
wrote:

On Thu, 26 Nov 2009 14:58:02 -0000, "John"
wrote:

It is a pity we are 'stuck' with relating brightness to wattage. If we used
a proper definitive measure of brightness then manufacturers would have to
be more honest.
Brightness is something that can be properly measured with a calibrated
instrument. Relating everything to a poor performing incandescent is not
good science.

(Lux - Candela - Lumens - whatever)

Foot candles.

Foot Lamberts

Apostilbs


Millinits

Derek

"Derek Geldard" wrote in message
...
On Thu, 26 Nov 2009 15:58:22 +0000, Derek Geldard
wrote:


On Thu, 26 Nov 2009 15:55:10 +0000, Derek Geldard
wrote:

On Thu, 26 Nov 2009 15:23:34 +0000, Frank Erskine
wrote:

On Thu, 26 Nov 2009 14:58:02 -0000, "John"
wrote:

It is a pity we are 'stuck' with relating brightness to wattage. If we
used
a proper definitive measure of brightness then manufacturers would have
to
be more honest.
Brightness is something that can be properly measured with a calibrated
instrument. Relating everything to a poor performing incandescent is
not
good science.

(Lux - Candela - Lumens - whatever)

Foot candles.

Foot Lamberts

Apostilbs


Millinits

magnitude and absolute magnitude.

On 26 Nov, 14:58, "John" wrote:
It is a pity we are 'stuck' with relating brightness to wattage. If we used
a proper definitive measure of brightness then manufacturers would have to
be more honest.

Why? Would anyone still understand it? Are such complex topics taught
in school science these days? Look at LED marketing, where they
cheerfully use the right words, but in any order that makes the snake-
oil sound best.

"Solid angle" is seemingly a concept that only lives in university-
level maths these days, so I don't know how they're going to teach the
difference between lumen and candela anyway.

On Thu, 26 Nov 2009 08:35:59 -0800 (PST), Andy Dingley wrote:

It is a pity we are 'stuck' with relating brightness to wattage.
If we
used a proper definitive measure of brightness then manufacturers
would
have to be more honest.

Why? Would anyone still understand it? Are such complex topics taught
in school science these days?

The packaging of most (if not all) bulbs these days has a lumen
value. You normally have to look for it though normally on the energy
chart thingy or the bit that tells you the voltage and offcical base
type, B22 etc.

Trouble is I don't know what 600 lumen compared to 700 is really
like, all I can say is that 700 is brighter. You can use the number
to do a better comparison between nominaly the same bulb though, one
"60W equivalent" against another "60W equivalent" CFL for instance.

--
Cheers
Dave.

"Dave Liquorice" wrote in message
ll.co.uk...
On Thu, 26 Nov 2009 08:35:59 -0800 (PST), Andy Dingley wrote:

It is a pity we are 'stuck' with relating brightness to wattage.
If we
used a proper definitive measure of brightness then manufacturers
would
have to be more honest.

Why? Would anyone still understand it? Are such complex topics taught
in school science these days?

The packaging of most (if not all) bulbs these days has a lumen
value. You normally have to look for it though normally on the energy
chart thingy or the bit that tells you the voltage and offcical base
type, B22 etc.

Trouble is I don't know what 600 lumen compared to 700 is really
like, all I can say is that 700 is brighter. You can use the number
to do a better comparison between nominaly the same bulb though, one
"60W equivalent" against another "60W equivalent" CFL for instance.

--
Cheers
Dave.


And how many lumens will a 700 lumen CFL give out after 6 months use?

Adam

In article o.uk,
"Dave Liquorice" writes:
On Thu, 26 Nov 2009 08:35:59 -0800 (PST), Andy Dingley wrote:

It is a pity we are 'stuck' with relating brightness to wattage.
If we
used a proper definitive measure of brightness then manufacturers
would
have to be more honest.

Why? Would anyone still understand it? Are such complex topics taught
in school science these days?

The packaging of most (if not all) bulbs these days has a lumen
value. You normally have to look for it though normally on the energy
chart thingy or the bit that tells you the voltage and offcical base
type, B22 etc.

Actually, I do look, but it's often not there.
EU rules about labeling of lamps is going to change this.
IIRC, it is going to require the lumen output to be the largest
rating on the packaging. It will also require the energy efficiency
rating, but manufacturers have managed to get the requirement to
specify the power rating (Watts) removed. Apparently, we're all
being confused by power ratings on lamps. If the power rating is
still specified on packaging, it must be in a smaller typeface than
the lumen output. If it is not specified, it must be available on
the manufacturer's website.

Trouble is I don't know what 600 lumen compared to 700 is really
like, all I can say is that 700 is brighter. You can use the number
to do a better comparison between nominaly the same bulb though, one
"60W equivalent" against another "60W equivalent" CFL for instance.

Here's a table from an old manufacturer's datasheet, but GLS
lamps haven't changed much in decades, so probably still correct:

GLS, Coiled coil, 240v, 1000hr

Watts Initial Lumens Average Lumens
40 410 390
60 700 665
100 1330 1260
150 2160 2075

2000hr (double life) are about 10% lower.

Perl (frosted) used to be around 2% lower, when the frosting was
etched with hydrofluoric acid. Due to H&S issues with hydrofluoric
acid, perl bulbs switched to a powder dusting a few years ago,
and I believe this is less efficient, but I don't have a figure.
Softone, golfball, mushroom, and other decorative lamps usually
have a painted coating, and this loses something nearer 20% of
the light output, or even more if tinted.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

On Thu, 26 Nov 2009 08:35:59 -0800 (PST), Andy Dingley wrote:

On 26 Nov, 14:58, "John" wrote:
It is a pity we are 'stuck' with relating brightness to wattage. If we used
a proper definitive measure of brightness then manufacturers would have to
be more honest.

Why? Would anyone still understand it? Are such complex topics taught
in school science these days? Look at LED marketing, where they
cheerfully use the right words, but in any order that makes the snake-
oil sound best.

People don't need to understand it, only to get used to it - how many
actually understood what a 100W tungsten lamp was? Its "brightness"? Colour
temperature? Angle? They were simply used to them and knew automatically
that they could adjust the amount of lighting in a room by increasing or
decreasing the wattage and roughly what they needed. The bulbs of any
particular manufacturer were generally similar and therefore there was no
problem replacing like for like. Rating CFLs by there wattage equivalence
was a good idea, but badly implemented. If the ratings had shown
equivalences to tungsten lamps that most people would have agreed with, and
all manufacturers stuck to, then they'd have been useful. Instead they have
taught people to be wary of believing manufacturers claims and ended up
with a lot of people installing CFLs that give subjectively poor lighting
that they are dissatisfied with.

SteveW

John wrote:
It is a pity we are 'stuck' with relating brightness to wattage.

It's worse wrt non-rechargeable batteries. How the hell does
"extra heavy duty" or "suitable for digital cameras" relate to
an energy storage capacity?

#Paul

On 26/11/09 22:41, wrote:

It's worse wrt non-rechargeable batteries. How the hell does
"extra heavy duty" or "suitable for digital cameras" relate to
an energy storage capacity?

Not much point in simply requiring alkalines, and zinc cells to display
their capacity in mAh, the internal resistance matters too compared to
NiMH and NiCd

Andrew Gabriel :
Perl (frosted) used to be around 2% lower, when the frosting was
etched with hydrofluoric acid. Due to H&S issues with hydrofluoric
acid, perl bulbs switched to a powder dusting a few years ago,
and I believe this is less efficient, but I don't have a figure.

What about those new-fangled PHP bulbs? :-)

--
Mike Barnes

In article ,
Mike Barnes writes:
Andrew Gabriel :
Perl (frosted) used to be around 2% lower, when the frosting was
etched with hydrofluoric acid. Due to H&S issues with hydrofluoric
acid, perl bulbs switched to a powder dusting a few years ago,
and I believe this is less efficient, but I don't have a figure.

What about those new-fangled PHP bulbs? :-)

Sorry, got perl on the brain at the moment.

--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]

Andrew Gabriel
wibbled on Friday 27 November 2009 11:09


Sorry, got perl on the brain at the moment.


Good. If it were python, I'd have to come round with my chicken bones to
cast out the evil

;-

--
Tim Watts

This space intentionally left blank...

On Nov 26, 8:58*am, "John" wrote:
It is a pity we are 'stuck' with relating brightness to wattage. If we used
a proper definitive measure of brightness then manufacturers would have to
be more honest.
Brightness is something that can be properly measured with a calibrated
instrument. Relating everything to a poor performing incandescent is not
good science.

(Lux - Candela - Lumens - whatever)

Here in the US all packages at stores I go to have lumen and watt
printed, If you want to compare Lumen hold a pack of incandesants and
compare. I just figure Cfls output 75% more in my shopping. If you
want to get technical to find the most efficient use you calculator
and run LPW a Lumen Per Watt number. For new types I just use Watts
and LPW as my guidline as some new cfls are 80% more efficient than
standard incandesants.

On Thu, 26 Nov 2009 22:41:41 +0000, news09paul wrote:

John wrote:
It is a pity we are 'stuck' with relating brightness to wattage.

It's worse wrt non-rechargeable batteries. How the hell does
"extra heavy duty" or "suitable for digital cameras" relate to
an energy storage capacity?

Not sure exactly - but I remember that my old Fuji digital camera ran on
AAs, and at the point it'd claim that the batteries were dead I could put
them in something else and still get a lot more life out of them. I assume
some classes of devices just fall over with part-discharged cells, and the
"heavy duty" ones help address this.

cheers

Jules

On Thu, 26 Nov 2009 14:58:02 +0000, John wrote:

It is a pity we are 'stuck' with relating brightness to wattage. If we used
a proper definitive measure of brightness then manufacturers would have to
be more honest.

Stick 1000 people in a room and get them all to rate the brightness of a
particular bulb on a scale of 1-10? :-)

Problem I have is that brightness is only part of what makes a light
'good' for a particular application, so just saying that one bulb gives
off as much light as another isn't necessarily good enough.

Jules wrote:

Not sure exactly - but I remember that my old Fuji digital camera ran on
AAs, and at the point it'd claim that the batteries were dead I could put
them in something else and still get a lot more life out of them.

Same here, our apparently "dead" batteries usually go into clocks and
continue to run for ages.

--
Mike Clarke