HDR, color management, krita, luts and other apps

[Kai-Uwe Behrmann]

Am 07.06.12, 10:59 +0200 schrieb Boudewijn Rempt:
> On Thu, 7 Jun 2012, Kai-Uwe Behrmann wrote:
>>>> Just if Krita is running in ocio mode, lcms would still need a shader or 
>>>> so.
>>> 
>>> There's existing code (in oyranos) that allows us to create a lookup 
>>> texture from an icc profile, so the last transform (sRGB->monitor) can 
>>> also be done in a shader.
>> 
>> A colour conversion chain like the following would be rather easy:
>> 
>> source colour space ->
>>  gamma + exposure ->
>>    ocio proofing colour space ->
>>      monitor colour space
>> 
>> Then put the above colour transform inside a 3Dtexture and
>> attach to the OpenGL image texture through a shader. So the complete 
>> conversion will run on the GPU. The shader can take additional arguments to 
>> support gamma and exposore.
>> 
>
> One interesting thing is gamma is apparently applied only after all the other 
> transforms in Mari.

Basically the HDR sliders, like gamma and exposure, are meant to bring the 
image values into a good visible range.

My guess is, the wrong order in Mari comes from a try to do something 
about monitor colour correction.
(But that is much better done in Krita by ICC profiles IMO).

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