GNOME Color Manager 2.31.1 - suggested improvements for screen cal/profiling

Florian Höch lists+gnome-color-manager at
Fri May 7 13:13:41 UTC 2010


recently I switched from the proprietary nvidia driver to noveau, so I 
could try the latest GCM :)

I noticed that for screen calibration, always a quality of 'low' is used 
and a shaper+matrix profile is created from varying colorpatch amounts 
and quality parameter.

Looking at the code, the 100-500 colorpatches used for the screen 
profiling really seem overkill for a simple matrix profile. So the first 
thing I'd suggest, is to always use a lower, fixed-amount colorpatch 
set: targen -d3 -e4 -g9 -m3, this yields 36 patches that most other 
profilers out there also seem to use and should give very good results 
with matrix profiles (of course YMMV, but imho it would be a good 
default. This is what I use in dispcalGUI atm). Then, I'd suggest 
colprof -qh for matrix profiles (lower quality levels will smooth the 
trc curves more, but I think high quality could model the device 
response more accurately). This shouldn't come at any speed penalty at 
the new low suggested colorpatch count. And, as GCM always does a 
calibration+profile, I'd use colprof -aS (single shaper+matrix) instead 
of -as (per channel shaper+matrix), as we can rely on the calibration 
already having established gray balance, thus no need to risk the per 
channel curves introducing banding or shimmering.

These changes would remove the need for the current three profile 
'precision' choices for screen calibration/profiling, so the last 
suggestion from me is to instead present the user with a choice for the 
calibration (dispcal) quality instead, or to get rid of the choice 
altogether (only for screen calibration/profiling ofcourse).

What do you think?

Am 06.05.2010 16:05, schrieb Richard Hughes:
> gnome-color-manager is a session program that makes it easy to manage, install
> and generate color profiles in the GNOME desktop.
> Version 2.31.1

Florian Höch

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