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tschmidt
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join:2000-11-12
Milford, NH
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reply to Raphion

Re: Another Reason to Not Use CFLs...

Interesting chart I have never understood fully what the CRI (color rendition index) means and the specific variation. Seems garden variety 32W T8 have a CRI of 78. Have no idea what the CRI of older T12 was.

I recently upgraded all our fixtures from T12 magnetic ballasts to T8 electronic ballasts. Can't say a see much of a difference in color and it is nice having them come on so quickly and no flicker.

I tried a pair of 3000k "kitchen" bulbs but they were so red both my wife an I agree the 4100k cool-white look much better.

/tom



Raphion

join:2000-10-14
Samsara
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Where CRI comes into play is with pigments or pigment mixtures that reflect colors that are in the light source's deadbands. For example, a pigment that admits light primarily around 520nm would appear much darker relative to a pigment that admits light around 545nm in the F32T8 light, while the same two pigments appear the same relative shade in natural light.

The colors seem to change from what they'd be in natural light simply because all the colors of light aren't there for the pigments to "work with".

CRI is largely determined by how complete and smooth the spectral distribution is.



Juggernaut
Irreverent or irrelevant?
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join:2006-09-05
Kelowna, BC
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reply to tschmidt

One trick I used to do with 4 footers was, use one cool white, and one warm white. Seemed to do the trick very nicely for a daylight type of light.
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"I fear the day that technology will surpass our human interaction. The world will have a generation of idiots." ~ Albert Einstein



SparkChaser
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Downingtown, PA
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reply to Raphion

said by Raphion:

Where CRI comes into play is with pigments or pigment mixtures that reflect colors that are in the light source's deadbands. For example, a pigment that admits light primarily around 520nm would appear much darker relative to a pigment that admits light around 545nm


Your explanation of the peaks in fluorescence are correct except that the color result is reversed. Pigments absorb light not emit it. The color is the area in the spectrum where the pigment doesn't absorb.
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"Facts do not cease to exist because they are ignored." - Aldous Huxley