In article <qqf4r39fjcie0dp0k0gj54tnsjmk5u30ha@4ax.com>,
Paul M. Eldridge <paul.eldridge@ns.sympatico.ca> writes:

I've used the GE 2D lamps in some fittings I've designed.
Their initial light output to final light output ratio is
not as bad as most other compact fluorescents. I use 2700K
and 3500K in different situations.

On Wed, 13 Feb 2008 19:40:46 -0500, Victor Roberts
xxx@lighting-research.com> wrote:

On Tue, 12 Feb 2008 21:12:38 -0400, Paul M. Eldridge
paul.eldridge@ns.sympatico.ca> wrote:

BTW, I've grown to dislike 2,700K CFLs and find the aforementioned
Sylvania a good choice for residential applications. The only 2,700K
CFL I like, and it happens to be my all time favorite, is GE's 2D.
For the life of me, I can't explain why I like this lamp so much more
than anything else, but there's something very pleasing about the
light it produces. Is there any rational explanation for this or do I
need to cut back on my happy pills?

Cheers,
Paul

Well, there is some physics driving the high CCT of CFLs. As
you know, in normal fluorescent lamps the mercury produces a
bit of blue and green light that is mixed with the slightly
yellow light from the phosphor to make white.

It turns out that the current density in most CFLs is so
high that they generate a lot of blue light. So much in
fact that many CFLs use only a two-component rare earth
phosphor mix instead of the normal three-component mix.
There is just too much blue to have any more coming from the
phosphor. (If the phosphor does have all three components,
then the blue component is reduced in small diameter lamps.)
The 2D is made in a rather large diameter tube, at least
measured by CFL standards. I believe it is T5 for most
wattages, while most lower power CFLs use T4 tubing or even
smaller. The larger diameter discharge in the 2D, along
with the length, reduces the current density, which in turn
reduces the amount of blue light produced by the discharge.
This allows a three-component rare earth phosphor to be used
which may lead to high quality light.

Thank you, Victor, for explaining this. I had long suspected the 2D's
unusual design might have something to do with this, but now I know
the full story. Again, to my untrained eye, the quality of the light
it produces is noticably better than anything else I've seen to date
and it's the only 2,700K lamp I find pleasing.

Best regards,
Paul

I've noticed the same thing and have long suspected that the width or
"fatness" of spectral lines - especially as found in fluorescent and HID
lamps -- has something to do with the color quality and acceptance of light
by users. That aspect of light and color is not well-captured in our current
color rendering and chromaticity metrics.

The same thing is likely to affect the perception of color quality for LEDs
and I've discussed the idea with the group that's looking at new color
measurement standards for LEDs. Plus the notion came up in the LRO Light
and Color Symposium in 2006, so there's now a bit of research on it.

The 2D lamp design got a lot of things right and, unfortunately, the full
range of features was never well undertood or promoted although I give GE
credit for keeping the lamp, as designed, in their product line. I
particularly liked the 55W version as used in the "Berkeley Lamp". It used
a desk lamp configuration and two lamps (one for uplight; the other for
downlight) with separate dimmers that still work better than any other CFL
dimmer that I've seen. See:
http://enews.lbl.gov/Science-Articles/Archive/cfl-tablelamp.html

Terry McGowan

On 12 Feb 2008 21:19:38 GMT, phil-news-nospam@ipal.net
wrote:

I have not yet seen color bulbs in CFL form, but it should not be
hard to make them. I'm sure they eventually will.

I'm not sure there is a big enough market for color CFLs.

On 13 Feb 2008 11:47:09 GMT, andrew@cucumber.demon.co.uk (Andrew
Gabriel) wrote:

In article <qqf4r39fjcie0dp0k0gj54tnsjmk5u30ha@4ax.com>,
Paul M. Eldridge <paul.eldridge@ns.sympatico.ca> writes:

I've used the GE 2D lamps in some fittings I've designed.
Their initial light output to final light output ratio is
not as bad as most other compact fluorescents. I use 2700K
and 3500K in different situations.

Hi Andrew,

I'm sure this lamp's unusual design and significantly larger size
makes fixture design a bit more challenging. Do you have links to any
of the work you've done with this particular lamp?

Hi Andrew,

I'm sure this lamp's unusual design and significantly larger size
makes fixture design a bit more challenging. Do you have links to any
of the work you've done with this particular lamp?

I must get round to putting up some pictures. The only one up
at the moment was the first one I converted...
http://www.cucumber.demon.co.uk/lights/diy2/
The ones I've done since then all use the 21W lamp.

The following might be amusing too, although it predates that:
http://www.cucumber.demon.co.uk/lights/diy/
The downlighters shown there are still in pretty continuous use
every day, for around 10 years now. Only one further capacitor
has had to be replaced since I wrote that article.

On Fri, 15 Feb 2008 09:44:44 GMT mroberds@worldnet.att.net wrote:
| Victor Roberts <xxx@lighting-research.com> wrote:
|> On 12 Feb 2008 21:19:38 GMT, phil-news-nospam@ipal.net
|> wrote:
|
|>> I have not yet seen color bulbs in CFL form, but it should not be
|>> hard to make them. I'm sure they eventually will.
|
|> I'm not sure there is a big enough market for color CFLs.
|
| FWIW, I saw colored CFLs at Wal-Mart while shopping earlier this
| evening. They were available in red, orange, yellow, green, blue,
| and "black"/UV. These were all 13 W (60 W equivalent) spiral CFLs by
| Feit Electric. The red, orange, green, and blue ones were marketed as
| "party bulbs"; the yellow one was actually marked as an anti-insect
| lamp. I took a close look at the red and orange ones, and I *think*
| they used colored glass, as opposed to a coating on the outside of
| clear glass. They sold for about $4 or $5 each.
|
| Wal-Mart sells another brand of anti-insect CFL (GE or Philips - I
| can't remember) that appears to have a translucent yellow plastic
| covering over a normal CFL.

Now all I need are some colored HID lights. Maybe they would know to
use different HID technologies for the different colors. Unfortunately
there is probably no market for 400 watt HID colored bulbs. They could
be used on giant Christmas trees, though.

Victor Roberts <xxx@lighting-research.com> wrote:
On 12 Feb 2008 21:19:38 GMT, phil-news-nospam@ipal.net
wrote:

I have not yet seen color bulbs in CFL form, but it should not be
hard to make them. I'm sure they eventually will.

I'm not sure there is a big enough market for color CFLs.

FWIW, I saw colored CFLs at Wal-Mart while shopping earlier this
evening. They were available in red, orange, yellow, green, blue,
and "black"/UV. These were all 13 W (60 W equivalent) spiral CFLs by
Feit Electric. The red, orange, green, and blue ones were marketed as
"party bulbs"; the yellow one was actually marked as an anti-insect
lamp. I took a close look at the red and orange ones, and I *think*
they used colored glass, as opposed to a coating on the outside of
clear glass. They sold for about $4 or $5 each.

phil-news-nospam@ipal.net> wrote in message
news:fp4fv04el5@news4.newsguy.com...
On Fri, 15 Feb 2008 09:44:44 GMT mroberds@worldnet.att.net wrote:
| Victor Roberts <xxx@lighting-research.com> wrote:
|> On 12 Feb 2008 21:19:38 GMT, phil-news-nospam@ipal.net
|> wrote:
|
|>> I have not yet seen color bulbs in CFL form, but it should not be
|>> hard to make them. I'm sure they eventually will.
|
|> I'm not sure there is a big enough market for color CFLs.
|
| FWIW, I saw colored CFLs at Wal-Mart while shopping earlier this
| evening. They were available in red, orange, yellow, green, blue,
| and "black"/UV. These were all 13 W (60 W equivalent) spiral CFLs by
| Feit Electric. The red, orange, green, and blue ones were marketed as
| "party bulbs"; the yellow one was actually marked as an anti-insect
| lamp. I took a close look at the red and orange ones, and I *think*
| they used colored glass, as opposed to a coating on the outside of
| clear glass. They sold for about $4 or $5 each.
|
| Wal-Mart sells another brand of anti-insect CFL (GE or Philips - I
| can't remember) that appears to have a translucent yellow plastic
| covering over a normal CFL.

Now all I need are some colored HID lights. Maybe they would know to
use different HID technologies for the different colors. Unfortunately
there is probably no market for 400 watt HID colored bulbs. They could
be used on giant Christmas trees, though.


Venture Lighting has sold metal halides with different saturated colors
using arc tube chemistry for some time. They're shy about listing the lamps
though and only show them as special order products. There's an example
photo at:
http://www.venturelighting.com/Applications/ArchitecturalStory.html

Terry McGowan

Victor Roberts wrote:
On Tue, 12 Feb 2008 21:12:38 -0400, Paul M. Eldridge
paul.eldridge@ns.sympatico.ca> wrote:

On Mon, 11 Feb 2008 23:29:12 -0500, Victor Roberts
xxx@lighting-research.com> wrote:

Over this past weekend I purchased a few screw-base CFLs.
I was greatly disappointed to find out that it was hard or
impossible to determine the color temperature of the CFLs
that I was trying to purchase....

Hi Victor,

Even when I'm sure I know what I'm getting I often prove myself
wrong. For example, Osram Sylvania's "Daylight Plus" CFLs have a
colour temperature of 3,500K and with a name like that I would fully
expect these lamps to be 5,000K, or perhaps higher given the "Plus"
designation. What marketing genius thought this up?

BTW, I've grown to dislike 2,700K CFLs and find the aforementioned
Sylvania a good choice for residential applications. The only 2,700K
CFL I like, and it happens to be my all time favorite, is GE's 2D.
For the life of me, I can't explain why I like this lamp so much more
than anything else, but there's something very pleasing about the
light it produces. Is there any rational explanation for this or do
I need to cut back on my happy pills?

Cheers,
Paul

Well, there is some physics driving the high CCT of CFLs. As
you know, in normal fluorescent lamps the mercury produces a
bit of blue and green light that is mixed with the slightly
yellow light from the phosphor to make white.

It turns out that the current density in most CFLs is so
high that they generate a lot of blue light. So much in
fact that many CFLs use only a two-component rare earth
phosphor mix instead of the normal three-component mix.
There is just too much blue to have any more coming from the
phosphor. (If the phosphor does have all three components,
then the blue component is reduced in small diameter lamps.)
The 2D is made in a rather large diameter tube, at least
measured by CFL standards. I believe it is T5 for most
wattages, while most lower power CFLs use T4 tubing or even
smaller. The larger diameter discharge in the 2D, along
with the length, reduces the current density, which in turn
reduces the amount of blue light produced by the discharge.
This allows a three-component rare earth phosphor to be used
which may lead to high quality light.

The above looks like it is validated with spectrogram [1.3.3], which corresponds
to a triphosphor fluorescent with a CCT of 2700K on my Amici page.

The 2700K CCT "triphosphor"'s spectrum, looks like it is truly "bi-phosphor" (as
far as I know ions of Terbium and Europium), since it has no blue emissions,
except the mercury blue line @435.8, which is very strong.

All other spectrograms of triphosphors (those with CCT's of 4000K, 6000K, 8000K
and 17000K, [1.3.4]/[1.3.5]/[1.3.8/[1.3.9]), contain additional continuous
emissions in the blue area around the blue mercury line, betraying the presence
of a "third" phosphor component which is not present in the 2700K CFL
fluorescent.

My question now is why was the 2700K CFL called "triphosphor" if its phosphors
were two-component only. The previous looks like a chronological inconsistency,
unless the "triphosphor" technology for higher CCT fluorescents was already
known at the time of production of 2700K CFLs.

Any opinions on the above?

On Thu, 14 Feb 2008 02:18:46 +0000 (UTC) Don Klipstein
don@manx.misty.com> wrote:

| In <k237r3l14mitcjlpk2erhh0fadvoqfr2cv@4ax.com>, V. Roberts wrote in
part:
|
|>Well, there is some physics driving the high CCT of CFLs. As
|>you know, in normal fluorescent lamps the mercury produces a
|>bit of blue and green light that is mixed with the slightly
|>yellow light from the phosphor to make white.
|
|>It turns out that the current density in most CFLs is so
|>high that they generate a lot of blue light. So much in
|>fact that many CFLs use only a two-component rare earth
|>phosphor mix instead of the normal three-component mix.
|>There is just too much blue to have any more coming from the
|>phosphor. (If the phosphor does have all three components,
|>then the blue component is reduced in small diameter lamps.)
|
| Somehow I see either 3 or 4 phosphor bands/features in the spectra of
| CFLs and "triphosphor" T8 fluorescents, Philips "Ultralume", etc. Could
| two of these spectral features be from the same phosphor?
|
| What I notice, in order from longer wavelength to shorter:
|
| 1. The strong orange-red linelike extremely narrow band around 611 nm,
| along with some very weak similarly narrow bands nearby from yellow to
| deep red,
|
| 2. a small group of wider but still very narrow bands in the green,
with
| the dominant feature maybe typically around 542 nm,
|
| 3. a dimmer, moderately narrow band in the green-blue/blue-green
| with its brightest part around 485-490 nm but extending into the
| blue-green around 500 nm, and
|
| 4. a wider still blue band, that with CFLs I usually only see when
| nominal CCT is at least 3500K, mainly from 440-475 or 440-480 nm or so.

Is there any kind of "catalog" of phosphor material and their spectral
lines that would identify what is being used.

My own interest is in find a way to make a CFL that could fill out the
spectrum fully enough to be visually seen much like incandescent. But
I don't know if there is enough phosphor material choices to do that.

I've considered the same for LED. I've seen LEDs listed for sale with
specific wavelengths and have seen at least 22 different wavelengths.
That might be quite a balancing act to get "flat white" out of it all,
especially with different rates of output decay over time.