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| Sarah Austin... |
 Posted: Thu Oct 22, 2009 11:01 pm |
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Victor Roberts <xxx at (no spam) lighting-research.com> wrote :
[quote]On Tue, 20 Oct 2009 23:03:18 -0500, Sarah Austin
SAustin at (no spam) pndfnospam.com> wrote:
Victor Roberts <xxx at (no spam) lighting-research.com> wrote :
On Tue, 20 Oct 2009 17:00:37 -0500, Sarah Austin
SAustin at (no spam) pndfnospam.com> wrote:
I went to Home Depot and had a look, and found some Ecosmart
"Bright White" 30 watt spirals, 2100 lumens, 3500k.
http://www.homedepot.com/Lighting-Fans-Light-Bulbs/EcoSmart/h_d1/N-
5yc1vZ1xhfZas2zZ4b8/R-100663852/h_d2/ProductDisplay?langId=-1&storeI
d= 10051&catalogId=10053
Here's how one looks next to an Ecosmart 5500k 27w
http://lakewoodcolorado.net/Sarah/DSCN5318.JPG
It's hard to tell whether the 5500k is just too blue, or the 3500k
is just too yellow.
It's impossible to tell from a photograph. The human
eye/brain system makes adjustments in real time that the
camera cannot capture.
I see that now. ( no pun intended :)
I turned on these new Bright Whites and a 40W 2700k one that I put in
the dining room drop-down lamp, and then compared with the 5500k ones
in the other rooms, and in context, the 2700k does look yellowish,
the 3500k does look mostly bright white, with a little yellow, and
the 5500k of course look bluish.
What about a pure white light?
What do you mean by "pure white"? White light comes in
various color temperatures. They are all "pure white."
Argh. :)
Well what I mean, is that if you look at these spectrum charts of
color temp, like the one at
http://www.soslightbulbs.com/colortemperaturechart.aspx
there's a small region of plain white that seems neither yellowish or
bluish. Pure white?
I have lost your original intent. Do you want a "white"
light for some specific purpose, such as color matching
fabrics? In that case the question of the best "white"
light has one answer, or set of answers.
However, if you want a color temperature that looks pleasing
in a particular environment, the question becomes far more
complicated. Noon time sunlight looks great outside.
However, as others have pointed out, if you use EXACTLY that
same color inside at typical indoor illumination levels,
most people would say it looks terrible, and also that it
looks "too blue." On the other hand, many people define
the color of tungsten halogen incandescent lamps as "crisp
white," yet this source has a color temperature near 3000K,
and would look yellowish with compared to sunlight or
photographed by a camera that is set for "daylight"
compensation.
I use a camera to document evidence for various legal cases
I am involved with. I know that, unless I am very careful,
objects that look one way to my eye can look very different
when they are captured by the camera. The human brain has a
way of compensating for the average color temperature of a
scene, while a camera does not, unless specifically
instructed by the human user.
[/quote]
I see what you're saying.
Well we have two main purposes for lighting here inside the house.
First is our pet birds, and in lieu of scientific evidence to the
contrary, which I'm working on finding out about now ( see other thread
) we use T8 Vita-Lites over their cages and they seem to be doing well
with it. ( anecdotal, I understand, for now )
Then we may have been operating under a false premise that I picked up
in the 70's in "Health and Light", that the same Vita-Lites are the best
indoor lighting for people's health. This thread has thrown that into
doubt now, and I'm keeping an open mind.
So I started experimenting a little. For indoor lighting outside of the
bedrooms, we want good reading light, and a bright cheerful look. Vita-
Lites, in retrospect, dont seem to provide that, they do look bluish.
Whether they also help with "SAD" is also questionable and I'm keeping
an open mind on that too. Maybe just getting outside in the winter is
best?
Of course our cockatoo wont do that. He's 1.6 lbs and can crack a walnut
shell in 1 second, and if he doesnt want to go outside, we dont push
him. 
He doesnt like it cold, like it's getting outside now in the Denver
area.
So I'm interested in that aspect.
For our lighting, I was experimenting recently and listing to some of
your thoughts here ( which I thank you for! ) and came across that
Bright White Ecosmart compact fluorescent from Home Depot ( 30 watt /
125 watt equiv, 2100 lumens, 3500k, no CRI rating ) and we like that
spectrum for our home offices ( we have two ). It's nice to read by, a
little on the warm side but just cozy, not too yellow or orange like
2700k seems.
But then I thought about the CRI aspect y'all mentioned here, so I did
some digging around.
I found what appear to be a very nice bulb in the 3500k, which I just
ordered a case of, for the two offices ( business expense ):
http://www.businesslights.com/tcp-xhl-32w-3500k-85-cri-t8-fluorescent-
lamp-case25-p-2060.html
TCP XHL 32W 3500K 85 CRI T8 Fluorescent Lamp case/25
[691231]
$47.50
TCP XHL 32W 3500K 85 CRI T8 Fluorescent Lamp case/25
TCP F32T8/835 3500K 85 CRI 3400 Lumens Fluorescent Lamp case/25
* On sale why quantities last
* 31032835XHL F32T8/835 Lamp Specifications
* 32 watts
* Color Temperature: 3500° Kelvin
* Color Rendering: 85 CRI
* MOL: 48 inches
* Initial Lumens: 3400
* Mean Lumens: 3200
* Average Rated Life: 24,000 hrs
* Minimum starting temperature: 10°C
* Low Mercury - TCLP Compliant
* Designed to operate on Instant Start ballasts
The CRI of 85 seems about as high as I can find in 3500k. The lumen
output looks great and the price is very nice.
In fact we may put fixtures in the bedrooms for these, for such things
as overhead light for cleaning, reading and finding things, while we
keep incandescents or 2700k compact fluorescents for bedtime winding
down, for the yellow spectrum. |
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| Don Klipstein... |
| Posted: Fri Oct 23, 2009 6:47 pm |
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In <slrnhdpkj3.dfr.don at (no spam) manx.misty.com>, I, Don Klipstein, wrote in part
on the Philips TL950 lamp with need for correction:
[quote]In <Xns9CA7CA416F673SntzldfrdSntzldfrdco at (no spam) 216.196.97.142>, Sarah Austin
wrote in part:
We also have pet birds here too, and this is what they say about lighting:
http://www.mmlights.com/bird%20lights.html
I had no idea Philips had one with a CRI of 98.
With about 2/3 the light output of their lamps with CRI of 84, and even
with a CRI of 98 they have a spiky spectrum. The usual CRI is "Ra8",
which tests only eight colors, and I suspect this lamp is "tuned for this
test".
[/quote]
Someone called me on this, and forwarded some documention including a
spectral power distribution curve for a Philips 941 lamp similar to their
TL950 lamp that I was commenting on.
I check out the TL950 in:
http://www.prismaecat.lighting.philips.com/ecat/Light/
ApplicationRouter.aspx?fh_secondid=927870095002_1&fh_view_size
=10000&fh_start_index=0&fh_eds=%c3%9f&fh_location=%2f%2fprof%2fus_US%
2fcategories%3c%7bfnppla%7d%2fcountries%3e%7bus_US%7d%2fstatus%3e%7bact%
7d%2fcategories%3c%7bc_err2fnppla_1830_np01lmp%7d%2fcategories%3c%
7bc_0022fnppla_1857_up_f%7d%2fcategories%3c%7bc_0012fnppla_1890_up_ft8%
7d%2f_rated_lamp_wattage%3e%7bplc_352%7d&fh_refview=lister&tab=&family=
&&left_nav=us_en&
Leading to, I hope the spectral power distribution is here:
http://www.prismaecat.lighting.philips.com/ecat/Light/Details.aspx?
fh_eds=%u00df&fh_location=%2f%2fprof%2fus_US%2fcategories%3c%7bfnppla%7d%
2fcountries%3e%7bus_US%7d%2fstatus%3e%7bact%7d%2fcategories%3c%7bc_
err2fnppla_1830_np01lmp%7d%2fcategories%3c%7bc_0022fnppla_1857_up_f%7d%
2fcategories%3c%7bc_0012fnppla_1890_up_ft8%7d%2f_rated_lamp_wattage%3e%
7bplc_352%7d&fh_refview=lister&fh_secondid=927870095002_1&fh_start_index=
0&fh_view_size=10000&left_nav=us_en&tab=images
This page has an option for images ready to change from "product photo"
to either of two options for spectral power distribution.
It is a lot less spiky than I remember. Unless it has changed, I am
remembering a spectrum of a different lamp achieving at least mid-90's CRI
with a spiky spectrum. The latter sounds likely to me, because it's been
a few years since I last checked this out - and accordingly I correct
myself on the spikyness/smoothness of the Philips TL950 lamp.
The phosphor output is indeed published to be a smooth broad band,
higher where strong mercury lines are lacking - in the blue-green and
more-visible portion of mid-red, lower where strong mercury lines are
present or where human vision has low sensitivity.
- Don Klipstein (don at (no spam) misty.com) |
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| Sarah Austin... |
| Posted: Fri Oct 23, 2009 11:24 pm |
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Guest
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don at (no spam) manx.misty.com (Don Klipstein) wrote :
[quote]http://www.prismaecat.lighting.philips.com/ecat/Light/
ApplicationRouter.aspx?fh_secondid=927870095002_1&fh_view_size
=10000&fh_start_index=0&fh_eds=%c3%9f&fh_location=%2f%2fprof%2fus_US%
2fcategories%3c%7bfnppla%7d%2fcountries%3e%7bus_US%7d%2fstatus%3e%7bac
t% 7d%2fcategories%3c%7bc_err2fnppla_1830_np01lmp%7d%2fcategories%3c%
7bc_0022fnppla_1857_up_f%7d%2fcategories%3c%7bc_0012fnppla_1890_up_ft8
%
7d%2f_rated_lamp_wattage%3e%7bplc_352%7d&fh_refview=lister&tab=&family
= &&left_nav=us_en&
[/quote]
Just a suggestion for future reference:
http://tinyurl.com/
:) |
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| Victor Roberts... |
| Posted: Sat Oct 24, 2009 5:58 am |
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Guest
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On Sat, 24 Oct 2009 04:47:28 +0000 (UTC), don at (no spam) manx.misty.com
(Don Klipstein) wrote:
[quote]In <slrnhdpkj3.dfr.don at (no spam) manx.misty.com>, I, Don Klipstein, wrote in part
on the Philips TL950 lamp with need for correction:
In <Xns9CA7CA416F673SntzldfrdSntzldfrdco at (no spam) 216.196.97.142>, Sarah Austin
wrote in part:
We also have pet birds here too, and this is what they say about lighting:
http://www.mmlights.com/bird%20lights.html
I had no idea Philips had one with a CRI of 98.
With about 2/3 the light output of their lamps with CRI of 84, and even
with a CRI of 98 they have a spiky spectrum. The usual CRI is "Ra8",
which tests only eight colors, and I suspect this lamp is "tuned for this
test".
Someone called me on this, and forwarded some documention including a
spectral power distribution curve for a Philips 941 lamp similar to their
TL950 lamp that I was commenting on.
I check out the TL950 in:
http://www.prismaecat.lighting.philips.com/ecat/Light/
ApplicationRouter.aspx?fh_secondid=927870095002_1&fh_view_size
=10000&fh_start_index=0&fh_eds=%c3%9f&fh_location=%2f%2fprof%2fus_US%
2fcategories%3c%7bfnppla%7d%2fcountries%3e%7bus_US%7d%2fstatus%3e%7bact%
7d%2fcategories%3c%7bc_err2fnppla_1830_np01lmp%7d%2fcategories%3c%
7bc_0022fnppla_1857_up_f%7d%2fcategories%3c%7bc_0012fnppla_1890_up_ft8%
7d%2f_rated_lamp_wattage%3e%7bplc_352%7d&fh_refview=lister&tab=&family=
&&left_nav=us_en&
Leading to, I hope the spectral power distribution is here:
http://www.prismaecat.lighting.philips.com/ecat/Light/Details.aspx?
fh_eds=%u00df&fh_location=%2f%2fprof%2fus_US%2fcategories%3c%7bfnppla%7d%
2fcountries%3e%7bus_US%7d%2fstatus%3e%7bact%7d%2fcategories%3c%7bc_
err2fnppla_1830_np01lmp%7d%2fcategories%3c%7bc_0022fnppla_1857_up_f%7d%
2fcategories%3c%7bc_0012fnppla_1890_up_ft8%7d%2f_rated_lamp_wattage%3e%
7bplc_352%7d&fh_refview=lister&fh_secondid=927870095002_1&fh_start_index=
0&fh_view_size=10000&left_nav=us_en&tab=images
This page has an option for images ready to change from "product photo"
to either of two options for spectral power distribution.
It is a lot less spiky than I remember. Unless it has changed, I am
remembering a spectrum of a different lamp achieving at least mid-90's CRI
with a spiky spectrum. The latter sounds likely to me, because it's been
a few years since I last checked this out - and accordingly I correct
myself on the spikyness/smoothness of the Philips TL950 lamp.
The phosphor output is indeed published to be a smooth broad band,
higher where strong mercury lines are lacking - in the blue-green and
more-visible portion of mid-red, lower where strong mercury lines are
present or where human vision has low sensitivity.
- Don Klipstein (don at (no spam) misty.com)
[/quote]
Are you are talking about the relative contribution to the
spectrum from the atomic emission lines vs. the contribution
from the phosphor? If so, the height of the spikes in the
SPD that come from atomic emission lines, relative to the
emission from the phosphor is totally meaningless - unless
the data is provided on the spectral resolution of the
spectrometer used.
I've taken data like this myself using a spectrometer with
variable slit width. The relative height of the atomic
emission lines (the mercury lines in an Ar-Hg discharge) to
the height of the phosphor output is a strong function of
the slit width, and hence the spectral resolution of the
spectrometer. By adjusting the slit width, the lines can be
made to "disappear" into the phosphor background, or, on the
other hand, the phosphor can be made to virtually disappear
while the atomic emission lines remain.
The reason is quite clear. The atomic emission lines are
narrower than the resolution of any normal spectrometer,
while the phosphor is a broad band source. As the slit
width is varied, the absolute peak intensity of the atomic
emission lines will remain constant, while the absolute peak
intensity of the phosphor emission will vary directly with
the spectral resolution. So, as the silt width is
decreased, the phosphor intensity decreases relative to the
intensity of the atomic emission lines. On the other hand,
as the slit width is increased, the absolute intensity of
the atomic emission lines is again constant, but the
absolute intensity of the phosphor emission goes up, and,
for large spectral resolutions, can equal the intensity of
the atomic emission lines.
--
Vic Roberts
http://www.RobertsResearchInc.com
http://www.cflfacts.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission. |
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| Don Klipstein... |
| Posted: Sat Oct 24, 2009 6:33 pm |
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Guest
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In <q4q5e5hhi22297sk1ejs7etekab7mrpq9q at (no spam) 4ax.com>, Victor Roberts wrote:
[quote]On Sat, 24 Oct 2009 04:47:28 +0000 (UTC), don at (no spam) manx.misty.com
(Don Klipstein) wrote:
In <slrnhdpkj3.dfr.don at (no spam) manx.misty.com>, I, Don Klipstein, wrote in part
on the Philips TL950 lamp with need for correction:
SNIP part of what Sarah Austin said to edit for space - she said in part:[/quote]
[quote]I had no idea Philips had one with a CRI of 98.
With about 2/3 the light output of their lamps with CRI of 84, and even
with a CRI of 98 they have a spiky spectrum. The usual CRI is "Ra8",
which tests only eight colors, and I suspect this lamp is "tuned for this
test".
Someone called me on this, and forwarded some documention including a
spectral power distribution curve for a Philips 941 lamp similar to their
TL950 lamp that I was commenting on.
[/quote]
(Now, I look back and see that forwarded to me was SPD of a TLD/940 lamp.)
[quote]I check out the TL950 in:
SNIP huge URL that I mentioned for this lamp in Philips online catalog
Leading to, I hope the spectral power distribution is here:
SNIP a similar huge URL that I mentioned
This page has an option for images ready to change from "product photo"
to either of two options for spectral power distribution.
It is a lot less spiky than I remember. Unless it has changed, I am
remembering a spectrum of a different lamp achieving at least mid-90's CRI
with a spiky spectrum. The latter sounds likely to me, because it's been
a few years since I last checked this out - and accordingly I correct
myself on the spikyness/smoothness of the Philips TL950 lamp.
The phosphor output is indeed published to be a smooth broad band,
higher where strong mercury lines are lacking - in the blue-green and
more-visible portion of mid-red, lower where strong mercury lines are
present or where human vision has low sensitivity.
- Don Klipstein (don at (no spam) misty.com)
Are you are talking about the relative contribution to the
spectrum from the atomic emission lines vs. the contribution
from the phosphor?
[/quote]
No. The spectrum that I remembered, apparently incorrectly for Philips
TL950, had not only spikes from mercury lines, but also moderately narrow
to almost-linelike-narrow phosphor bands like the TL850 has, only 2 or 3
more of them including one in the red (longer than 611 nm, maybe around
630 nm) and one in the yellow.
<Back to what Vic wrote - in short and in my words, if I got it right,
explanation that tall spikes in a spectral power distribution curve may
amount to not a whole lot of spectral content if the spectrometer has
narrow resolution>
- Don Klipstein (don at (no spam) misty.com) |
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