Tuesday, May 22, 2012

CIE Library: Illuminants

And, here's an image of what the illuminants look like using the 1964 observer:

Just a couple quick notes about this image: The spectra are rendered using a gamma of 1.8, which seems to work best, aesthetically, however, I do think they're meant to be rendered with a linear gamma. The first is the standard observer, second is CIE Illuminant A, and the third is D65, after that are the fluorescent illuminants, F1-F12 the first 6 are standard fluorescent illumination the next 3 are high CRI illuminants, and the final 3 are described as three band illuminants.

You'll note in all of the fluorescent samples that the light has strong peaks in the green and blue ranges, and with the exception of the 3-band examples, they all have a relatively weak yellow peak.

The high-cri examples do a little better than the standard fluorescent ones, but not much. I imagine you'd get less metameric failure with that lighting. This also explains the green cast in camera images recorded under fluorescent lighting conditions. It appears F3 and F4 maybe "warm white" while the rest are cool white.

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