Let's talk about the rgb sensitivity in raw.

Started Dec 23, 2012 | Discussions thread
crames
Regular MemberPosts: 188
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Re: How RAW RGB Channel Data is derived from RGB Photosite Image Data
In reply to Iliah Borg, Dec 27, 2012

Iliah Borg wrote:

Is is not to be expected that the a* and b* CIELAB coordinates will change with changing luminance?

Depends on the goal and the constraints. Convert to original Munsell and see.

See what? Since the Munsell system is another Chroma-based model like CIELAB a* b*, there is still the problem with dependence on Lightness or Munsell Value.

What is constant in your example is hue and saturation (location on a chromaticity diagram). They really are the "same color," only with a different lightness.

They are not constant, but you can find a model where they appear constant.

If the color ratios are constant, then hue and saturation (not Chroma) is constant despite changes in luminance, at least for all the CIE models that include saturation.

Perhaps a better model to use would be one where (unlike CIELAB) luminance is separated from chromaticity, such as xyY.

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