[Digikam-users] Some color management questions

[Rainer Krienke]

Hello,

i run digikam 0.10 on my openSuSE 11.1 box. All my photos are in sRGB 
colorspace. JPG files I convert from my cameras NEF files (using bibble) are 
also in sRGB. In digikam colormanagement is disabled. So far so good. Up to 
now I never had any color problems.

Today a friend send me some JPG photos. I know he also shoots in RAW (Nikon 
D300) and then converts these files into either tiff or JPG. We spent a 
holiday together and now exchanged some photos, he sent me JPG files. He is 
working with windows, I guess to remember he is using Nikon Capture and Adobe 
Photoshop to process his photos.

When I saw his photos and compared them to mine the first thing that I saw, 
was that color saturation in all of his photos looks to me rather small. Some 
photos actually look a little pastel-colored and there is some yellow tint in 
quite all of his photos. Color is not completely wrong but looks in my eyes  a 
little strange.

I looked at the photos XMP metadata where I found a Photoshop section. In this 
section there is an entry "ICCProfile" with a value of "Adobe RGB (1998)".

- Does this mean that color in these JPGs is in Adobe RGB 1998 and not in 
sRGB? If yes then perhaps this difference in colorspace could be the reason 
for the pale colors, couldn't it?

- What should digikam actually do with a photo that is in Adobe RGB color 
space?  Would it be automatically convert it to sRGB when I look at it? Do I 
have to activate colormanagement in digikam to get things right even if I just 
want to look at these photos?

- Can a JPG actually contain an image in Adobe RGB or is (or should be) the 
colorspace by definition sRGB in all JPGs? 

I am actually unsure if I really have a color problem or if everything is the 
way it should be, but since my friend does not live next door I cannot just 
take a look on his monitor to see if he intended this "special" color look.

Thanks for your help
Rainer

-- 
Rainer Krienke, Uni Koblenz, Rechenzentrum, A22, Universitaetsstrasse  1
56070 Koblenz, http://www.uni-koblenz.de/~krienke, Tel: +49261287 1312
PGP: http://www.uni-koblenz.de/~krienke/mypgp.html,Fax: +49261287 1001312