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Topic: More on CMY vs. CMYK - light sources (54 lines)
1) From: Irene and Lubos Palounek
"I know that the halogen type lights used in track lighting systems are very
close to the spectrum of sunlight"
Kevin, "very close" is relative.  I think that you are almost 100% right for
the new lines of halogen lights, such as the Osram - Sylvania Tru-Aim IR
MR16 Light Bulbs with their almost 100 CRI attributes, some Sun-A-Lux
products, some Biolightsystem products, perhaps some Ott-Lite lights,
perhaps the  new GE Silv-IR, some Verilux lights, and similar lights from
other manufacturers. (It is easy to search the Internet for those specific
light sources. It is not so easy to find general and up-to-date information
on the subject.)
You are  probably 100% right for our practical purposes-- for those purposes
I would not argue the difference between 99.6 and 100. However, I believe
that the older halogen lights used in track lighting have lower CRI; I might
be wrong and perhaps I have obsolete data. Will you please refer us to the
source of your information for different types of halogen lights used in
track lighting? Why to pay more for "special" lights if, perhaps, the new
versions of "regular" and inexpensive lights are good enough? It seems that
you know more about this subject than I and some of the others on this list;
please help.
"So much to learn - so little time"  -- and things do change quite rapidly!
Visible wavelengths cover a range from approximately 400 to 800 nm and I
think that's the range we are interested in, correct? The solar light
spectrum has not changed during our life time; an example is on the
following page:http://csep10.phys.utk.edu/astr162/lect/sun/spectrum.htmlColor Rendering Index (CRI) is a term used to describe the extent to which
an artificial light source is able to render the "true" color of objects as
seen by natural outdoor sunlight which has a CRI of 100. The closer the CRI
of a lamp is to 100, the more "true" it renders colors.  Generally, a lower
CRI indicates that some colors may appear unnatural when illuminated by a
lamp.  When I looked into it some years ago, it was said that no artificial
light source has a CRI of 100. Has that changed recently?
Where to find spectra for specific "halogen type lights used in track
lighting systems that are very close to the spectrum of sunlight"?
Regards, Lubos.
P.S.
I thought that CMY and CMYK generally refer to inks, while RGB refers to
light sources. That Red, Green, and Blue are the additive primary colors,
colors of light. The Cyan, Yellow, and Magenta are the subtractive primary
colors of pigments. Am I wrong here, too?
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