Regarding color conversion (RGB->CMYK)

[Johan Holst Nielsen]

Hi all,

I hope someone can help me.

I have do do a color conversion from RGB to CMYK. It's harder than I 
thought :D Anyway, here is my problem.

I tried some differents ways to do it - I have a TIFF RGB file that I 
need to convert to CMYK colorspace.

First of all I tried ImageMagick - it works - or it doesn't. Its give me 
an CMYK TIFF - but with way wrong colors :( Nothing seems to be quite 
right in that picture - tried google - and it seems that other people 
have the same problem as me :(

After that my thoughts was on PIL (Python Imaging Library). The colors 
was better - but to bright - cause it didn't include K (so it was 
basicly a RGB=>CMY conversion - Black is 100% Cyan, Magenta and Yellow).
I tried some googling - and again - some people said that PIL shouldn't 
be used for images that should be printed "professional".

Now, I don't have any clue about what I need to do? Is there another way 
to solve my problems? Any tools that can convert somehow? Or any kind of 
examples I can try to read?

It have to run on a Linux box - Python, Perl, PHP, bash whatever :(

Though about GIMP - but can find any information about how I can do a 
conversion in command-line? Any one having knowlegde about this?

Looking forward to hear from you and I will appreciate any kind of help.

With Best Regards,
Johan Holst Nielsen