[Openicc] Questions about ... CM for Displays

[Chris Murphy]

On Feb 13, 2008, at 3:21 AM, Jan-Peter Homann wrote:

> Hello list,
> Concerning colormanagement to the display, we have following use  
> cases:
> 1) all content shown on the display has the same colorspace e.g. sRGB
> This could be colormanagemed by LUTS in the Video-Card or in in the  
> monitor

I disagree.

LCDs are very non-linear in their behavior, not very well behaved, at  
least until  you get to higher end displays. Thus to compensate for  
their behavior necessitates full 3D LUT ICC profiles, and better than  
8bpc of precision. The LUT in a video card is 1-D and sometimes not  
even 8bpc of precision. It's just for defining a set of transfer  
functions (curves) per channel. That's it. You can compensate for the  
difference in tone response curve between sRGB and display TRC with  
this LUT. You can't do any kind of perceptual gamut mapping with such  
a LUT. It would do nothing for display compensation to wide gamut  
displays at all. A CMS needs to do this.


Chris Murphy