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Unfortunately, cameras only capture RGB values, not a whole spectrum. It is impossible to perfectly color-correct the image unless you know both the spectrum of

Unfortunately, cameras only capture RGB values, not a whole spectrum. It is impossible to perfectly color-correct the image unless you know both the spectrum of the light source and of the materials in the scene. A reference card with lots of colors still only provides you with the known spectra of the colors on that card, it still might not contain a color with the exact same spectrum as that flower you are trying to photograph for example. Another issue is that even if you have the perfect photography + post-processing setup, when I see the result it might be on a non-calibrated monitor, or on paper but in a room with non-perfect lighting, and perhaps I was just looking at something else a second before and my brain's auto white-balance hasn't caught up yet. So I might still not perceive it as was intended. This is why that gold dress looks blue to some people. The patch of grey on the reference scale + good lighting of the scene to begin with will get you 99% of the way, the remaining 1% is extremely hard to get right, if at all possible.

stared 5y ago
Well, in principle you get 3 degrees of freedom instead of 1 (though, I would love to see camers with more than 3 color filters). In practice you do 2 anyway (with exposure correction being used even more often than white balance). So I agree that more than that is usually not worth the effort. From my amateour photography experince - with strange lighting you cannot do much anyway.
- hatsunearu 5y ago
  With multiple light sources, the white balance is undefined and you need to compromise somehow, yeah. Even a scene where there is strong sunlight and a bright blue sky will make white balancing quite difficult, as the shadows are lit with sky blue skylight and the sunlit parts are lit with the sun. I use darktable and it's possible to correct the blue tint in shadows, but like... it's annoying. And at some point I'd say fuck it and just accept that photography is not a science.

stared 5y ago

Well, in principle you get 3 degrees of freedom instead of 1 (though, I would love to see camers with more than 3 color filters). In practice you do 2 anyway (with exposure correction being used even more often than white balance). So I agree that more than that is usually not worth the effort. From my amateour photography experince - with strange lighting you cannot do much anyway.

hatsunearu 5y ago
With multiple light sources, the white balance is undefined and you need to compromise somehow, yeah. Even a scene where there is strong sunlight and a bright blue sky will make white balancing quite difficult, as the shadows are lit with sky blue skylight and the sunlit parts are lit with the sun. I use darktable and it's possible to correct the blue tint in shadows, but like... it's annoying. And at some point I'd say fuck it and just accept that photography is not a science.