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Re: Question about the Sylvania light posting
"Ben B." <benrx at naxs_net> wrote:
> I'm a couple days behind on my reading, so sorry this is a little late.
> I have a question about the post below. I was curious about the Sylvania
> lights and looked at the file. As I thought I understood it, CRI compared a
> light's quality to Sunlight and a value of 100 most closely represented the
> that of the Sun. Also, a temperature of 5,500K is considered close to
> natural sunlight. If you look at the CRI and the temp. of some of the
> lights in the file, there is no correlation. Some 3500K lights have a
> higher CRI than a 5000K light. Apparently I have something confused. Could
> someone fill me in?
CRI and color temp. are not correlated. Quoting from
"CRI is a unit of measure that defines how well colors are rendered by
different illumination conditions in comparison to a standard (i.e. a
thermal radiator or daylight)".
Note that sunlight does not enter the definition at all. When measuring
the CRI of a, say, 3,500K light source, the standard to be used is a
3,500K thermal source (black body), not a 5,000K source. This is why
incandescent bulbs always have a CRI of 100 by definition, since they
*are* thermal sources. It doesn't mean that they produce sunlight though.
- Ivo Busko
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