On 11 Nov, 15:07, pete wrote:
On Tue, 11 Nov 2008 05:53:59 -0800 (PST), wrote:

The packaging is another example of marketing 'though. It claims the
11W is equivalent to 60W, and even gives a comparison of a 60W
incandescent providing 620 Lm, and itself offering 640 Lm. The only
problem with that is that a standard 240 V GLS 60W (Frosted) *gives
700 lumen, and it is the so-called 'softlight elegance' that offers
only 620 lumen.

After the initial discussion here about the brightness of these bulbs
I did some real-life tests. The setup was a sheet of A0 white paper
(from a flip-chart) laid flat on a table underneath a ceiling hung
light fitting with a lampshade. I pointed my DSLR at the paper and
noted the exposure timing. All other parameters remaining constant.

With a "normal" 60W pearl bulb the exposure meter reported 1/90 sec.
With an 11W CFL, the meter said 1/60 sec.
With an 8W CFL the meter also read 1/60 sec.

While I'm only looking at _relative_ measurements, and I was concerned
only with light for reading by (hence seeing what was reflected off the
paper), it supported my view that CFLs were dimmer than tungsten bulbs.
The interesting result was that 8W bulbs threw just as much light in
a downwards direction as the 11W bulbs. I reckon this is because the
light is projected downwards off the end of the bulbs, not off the
body. Since 11W bulbs have longer bodies, but the same x-section, the
usable light output is the same. The sideways emitted light is largely
absorbed by the lamp shade (hence it's name!), even though it had a matte
white interior.

Now I'm quite happy to accept the manufacturers' claims that the absolute
light output, measured in laboratory conditions, is similar to tungstens.
However, I have convinced myself that in a normal domestic ceiling-hung
fitting, the shape of the bulb reduces the amount of usable light by far
too much.

(Sorry about the full quote, but I think it is all needed for the
context)

That is why lamp light output is measured by using an integrating
sphe

http://www.lightingsciences.com/stat...ing-sphere.pdf
http://physics.nist.gov/Divisions/Di...ela/photo.html

Lamp manufacturers will give the light intensity distribution of their
lamps - see p99 of:

http://www.gelighting.com/eu/resourc...luorescent.pdf

....and you'll note from the spectra on the same page that it is not a
black body spectrum. Your DSLR light meter's response will vary
according to the wavelength of light incident upon it. My camera will
automatically recognise daylight, tungsten, fluorescent, and candle
lighting and adjust exposure automatically: it is possible yours may
not have, and has got the exposure incorrect.

I'm not trying to defend CFLs here, but in order to criticise, the
measurements need to be correct, and I'm afraid you have not
controlled for all the significant variables.

I think it is Cadmium Selenide photodetectors that have a wavelength
response that is substantially similar to (but not identical to) the
human eye. A fair amount of work has been done to determine and codify
the differences so comparisons between different sources of light can
be made in a valid way. I suspect your quick check with the camera is
insufficiently rigorous. Sorry. You do bring up an intereasting point
about light distribution though. Now that you have mentioned it, I do
notice the same.

Regards,

Sid

pete wrote:
On Tue, 11 Nov 2008 05:53:59 -0800 (PST), wrote:
The packaging is another example of marketing 'though. It claims the
11W is equivalent to 60W, and even gives a comparison of a 60W
incandescent providing 620 Lm, and itself offering 640 Lm. The only
problem with that is that a standard 240 V GLS 60W (Frosted) gives
700 lumen, and it is the so-called 'softlight elegance' that offers
only 620 lumen.

After the initial discussion here about the brightness of these bulbs
I did some real-life tests. The setup was a sheet of A0 white paper
(from a flip-chart) laid flat on a table underneath a ceiling hung
light fitting with a lampshade. I pointed my DSLR at the paper and
noted the exposure timing. All other parameters remaining constant.

With a "normal" 60W pearl bulb the exposure meter reported 1/90 sec.
With an 11W CFL, the meter said 1/60 sec.
With an 8W CFL the meter also read 1/60 sec.

While I'm only looking at _relative_ measurements, and I was concerned
only with light for reading by (hence seeing what was reflected off the
paper), it supported my view that CFLs were dimmer than tungsten bulbs.
The interesting result was that 8W bulbs threw just as much light in
a downwards direction as the 11W bulbs. I reckon this is because the
light is projected downwards off the end of the bulbs, not off the
body. Since 11W bulbs have longer bodies, but the same x-section, the
usable light output is the same. The sideways emitted light is largely
absorbed by the lamp shade (hence it's name!), even though it had a matte
white interior.

Now I'm quite happy to accept the manufacturers' claims that the absolute
light output, measured in laboratory conditions, is similar to tungstens.
However, I have convinced myself that in a normal domestic ceiling-hung
fitting, the shape of the bulb reduces the amount of usable light by far
too much.


Thats is fairly consistent with my findings as well. an 11W spiral is
similar to a 40W bulb. The longer things are a bit better, especially
sideways. I have some in some outside lamps where light comes out more
sideways, and there they are close to a 60W.

On Nov 11, 3:35*pm, wrote:
On 11 Nov, 15:07, pete wrote:



On Tue, 11 Nov 2008 05:53:59 -0800 (PST), wrote:

The packaging is another example of marketing 'though. It claims the
11W is equivalent to 60W, and even gives a comparison of a 60W
incandescent providing 620 Lm, and itself offering 640 Lm. The only
problem with that is that a standard 240 V GLS 60W (Frosted) *gives
700 lumen, and it is the so-called 'softlight elegance' that offers
only 620 lumen.

After the initial discussion here about the brightness of these bulbs
I did some real-life tests. The setup was a sheet of A0 white paper
(from a flip-chart) laid flat on a table underneath a ceiling hung
light fitting with a lampshade. I pointed my DSLR at the paper and
noted the exposure timing. All other parameters remaining constant.

With a "normal" 60W pearl bulb the exposure meter reported 1/90 sec.
With an 11W CFL, the meter said 1/60 sec.
With an 8W CFL the meter also read 1/60 sec.

While I'm only looking at _relative_ measurements, and I was concerned
only with light for reading by (hence seeing what was reflected off the
paper), it supported my view that CFLs were dimmer than tungsten bulbs.
The interesting result was that 8W bulbs threw just as much light in
a downwards direction as the 11W bulbs. I reckon this is because the
light is projected downwards off the end of the bulbs, not off the
body. Since 11W bulbs have longer bodies, but the same x-section, the
usable light output is the same. The sideways emitted light is largely
absorbed by the lamp shade (hence it's name!), even though it had a matte
white interior.

Now I'm quite happy to accept the manufacturers' claims that the absolute
light output, measured in laboratory conditions, is similar to tungstens.
However, I have convinced myself that in a normal domestic ceiling-hung
fitting, the shape of the bulb reduces the amount of usable light by far
too much.

(Sorry about the full quote, but I think it is all needed for the
context)

That is why lamp light output is measured by using an integrating
sphe

http://www.lightingsciences.com/stat...to/Candela/pho...

Lamp manufacturers will give the light intensity distribution of their
lamps - see p99 of:

http://www.gelighting.com/eu/resourc...ry/catalogs/la...

...and you'll note from the spectra on the same page that it is not a
black body spectrum. Your DSLR light meter's response will vary
according to the wavelength of light incident upon it. My camera will
automatically recognise daylight, tungsten, fluorescent, and candle
lighting and adjust exposure automatically: it is possible yours may
not have, and has got the exposure incorrect.

I'm not trying to defend CFLs here, but in order to criticise, the
measurements need to be correct, and I'm afraid you have not
controlled for all the significant variables.

I think it is Cadmium Selenide photodetectors that have a wavelength
response that is substantially similar to (but not identical to) the
human eye. A fair amount of work has been done to determine and codify
the differences so comparisons between different sources of light can
be made in a valid way. I suspect your quick check with the camera is
insufficiently rigorous. Sorry. You do bring up an intereasting point
about light distribution though. Now that you have mentioned it, I do
notice the same.

Regards,

Sid

With the popular stick shape there's less light directed downward,
giving more even lighting. Suits me.


NT

On Fri, 07 Nov 2008 07:55:33 +0000, Gary wrote:

It's good that this is a none controversial subject upon which everyone
agrees.

So. I've been trying these halogen capsule based energy savers. I like them.

I put a so-called 60W (claimed) CFL in one of our pair of ceiling roses,
and a halogen capsule 60W (claimed - input power 43W) in the other. The
difference is outstanding. The halogen capsule light bulb is so much
brighter, and.. It comes on when you turn it on. Plus they look good
with the clear envelope and the little halogen capsule inside.

I don't think the lifetime of these halogen energy savers will be
anything like as good as the CFL but it's worth it in order to be able
to see. In my opinion these things are the business. An ingenious way to
get the same (or, better, even perhaps) light quality as tungsten filament.

I wouldn't use them in situations where I have to leave a light on for
most of the day, like at the top of our staircase (no windows) but for
times when you want good light for a few hours or something and you
still want to save some energy, I suggest you give them a try.


I put a double socket up with two 20W CFLs to give a supposed
equivalent to 2 100W bulbs. No idea if they are but they are certainly
bright enough for me and only 40W compared to the original 150W.

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Alang
saying something like:

I put a double socket up with two 20W CFLs to give a supposed
equivalent to 2 100W bulbs.

I've been trying to find those two-way lamp adapters for just this
reason. Was yours old stock kicking around a kitchen drawer, or did you
find one in a shop?

Alang wrote in message
...


I put a double socket up with two 20W CFLs to give a supposed
equivalent to 2 100W bulbs. No idea if they are but they are certainly
bright enough for me and only 40W compared to the original 150W.

What a good idea
Somewhere I have a box of 50+ of them, all NOS
(Surprise unrelated addition in a bulk auction lot purchase)


-

Grimly Curmudgeon wrote:
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Alang
saying something like:

I put a double socket up with two 20W CFLs to give a supposed
equivalent to 2 100W bulbs.

I've been trying to find those two-way lamp adapters for just this
reason. Was yours old stock kicking around a kitchen drawer, or did you
find one in a shop?

BC adaptors were banned from sale in about 1970, but not from use.
They're still around but not exactly common.


NT

In article ,
Grimly Curmudgeon writes:
We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Alang
saying something like:

I put a double socket up with two 20W CFLs to give a supposed
equivalent to 2 100W bulbs.

I've been trying to find those two-way lamp adapters for just this
reason. Was yours old stock kicking around a kitchen drawer, or did you
find one in a shop?

Well, you can always make your own...

http://www.bigclive.com/hamster.htm

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

On Wed, 12 Nov 2008 22:52:18 +0000, Grimly Curmudgeon
wrote:

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember Alang
saying something like:

I put a double socket up with two 20W CFLs to give a supposed
equivalent to 2 100W bulbs.

I've been trying to find those two-way lamp adapters for just this
reason. Was yours old stock kicking around a kitchen drawer, or did you
find one in a shop?

Had it for about 40 years. I've got a switched one too. an sometimes
get them in car boot sales

I was tempted to make one and pot it up with epoxy and slate powder.
Idea is to get both lamps offset and horizontal so the whole lot fits
in a 12 inch dia shade without touching the side

We were somewhere around Barstow, on the edge of the desert, when the
drugs began to take hold. I remember (Andrew
Gabriel) saying something like:

I put a double socket up with two 20W CFLs to give a supposed
equivalent to 2 100W bulbs.

I've been trying to find those two-way lamp adapters for just this
reason. Was yours old stock kicking around a kitchen drawer, or did you
find one in a shop?

Well, you can always make your own...

http://www.bigclive.com/hamster.htm

WhooHoo! That's actually a bloody good idea, but a bit less Sputniky
like. It would be easy enough to make a simple two or three way using
pendant fittings.