2007.10.23 21:02 "Re: [Tiff] Floating-point 32bit sample data", by Kai-Uwe Behrmann

Am 23.10.07, 19:21 +0200 schrieb Joris:

Are floating point RGB data stored gamma corrected or linearized?

The data is best stored in a linear matrix space, much like camera RAW. OpenEXR even suggests now to use XYZ instead of RGB.

Only, there isn't a photometric value for it.

RGB, without embedded ICC profile, is mostly agreed upon to mean sRGB. Another and probably more unambigious way to store color data, even if I feel RGB is regarded sRGB by just about anyone, is CIE L*a*b*, and there's a proper photometric for that one and a totally unambigious scale and meaning for floating point CIE L*a*b* data.

How would you handle the different gammas in CIE*Lab for typical floating point HDR content?

Of course you are right to point out, that a ICC profile is needed to give a meaning to the image colours.

kind regards

Kai-Uwe Behrmann
--
developing for colour management
www.behrmann.name + www.oyranos.org + www.cinepaint.org