Color profiles, engineering or art?

Started 3 months ago | Discussions thread
Iliah Borg Forum Pro • Posts: 27,578
Re: Color profiles, engineering or art?
1

pixelgenius wrote:

Iliah Borg wrote:

Erik Kaffehr wrote:

Hi,

I saw this video: https://youtu.be/AZdzcaaqaeY discussing color between C1 and LR.

I think the video is interesting but ignores some subtle issues like white balance.

But it states the 'Image Quality Professor' at Capture One collects something like 7000 images to adjust the color profiles.

In a way, I would assume that the best way to build a profile would be to automatically generate a conversion from camera RGB signals to XYZ using a good learning set. Or to create a profile from the camera spectral response curve, if that is known.

On top we could apply a 'look'.

Just to say, I have noted that Capture One has some real oddities, mostly turning purple in blue.

This is Adobe Standard on my Phase One P45+

While this is Capture One's rendition, both adjusted for a grey card in the image.

The real color, measured with my Color Munki Photo is this one:

Taken from the petals, spectral measurements (D50, I would think).

Using my Sony Alpha 99, there was also significant blue shift with C1:

Sony Alpha 99, Capture One

Sony Alpha 99, Adobe Standard

This doesn't mean that C1 has bad color, but it may seem that handling deep bluish purples it may be very sensitive to WB errors.

This tests were old, but I still see that C1 has a tendency to turn purple into blue.

Best regards

Erik

As Bruce Lindbloom noted more than once, the root of "blue <-> purple" problem is in perceptional non-uniformity of Lab space.

This is an interesting read too:

Lab is warped

http://www.colorwiki.com/wiki/Lab_is_warped

Thank you. Warped and perceptually irregularly compressed, leading, for example, to abrupt transitions of skin tones to green if a proper LUT is not in place to take care of Lab deficiencies.

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