[colord] Display of CMYK images too saturated

[Michael Below]

Hi,

Am Fr 23 Jan 2015 20:37:32 CET
schrieb Richard Hughes <hughsient at gmail.com>:

> On 3 January 2015 at 14:02, Michael Below <below at judiz.de> wrote:
> > I have filed a bug against colord in Debian since most programs show
> > CMYK images in an oversaturated way:
> 
> What is your auto-edid profile? Maybe the display is reporting crazy
> primaries. You can also turn this off in the gnome-control-center
> color panel for debugging.

Sorry for accusing colord: it seems like libjpeg is using a "lucky
guess" method to convert CMYK to RGB.

int k = ptr[3]; 
ptr2[3] = 0xFF; 
ptr2[2] = k * ptr[0] / 255; 
ptr2[1] = k * ptr[1] / 255; 
ptr2[0] = k * ptr[2] / 255;

https://bugs.kde.org/show_bug.cgi?id=172196

Since the image viewers I am struggling with seem to be getting wrong
input from libjpeg, without any attempt to use a CMS, there is no
connection to colord.

About my display: It's actually hardware calibrated, and I think
the accuracy is reasonable (LG 27EA83, using LG software and a i1
Display Pro, feeding the resulting ICC to colord/GNOME).

Cheers
Michael