Regarding color conversion (RGB->CMYK)

M.E.Farmer mefjr75 at hotmail.com
Sat Nov 13 01:55:15 CET 2004


Johan Holst Nielsen <spam at phpgeek.dk> wrote in message news:<4194bd54$0$75308$edfadb0f at dread15.news.tele.dk>...
> 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.
>[snip]
> 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".
This link might be a start.
'http://mail.python.org/pipermail/image-sig/2001-March/001386.html'
Basically you are right the conversion is not straightforward and is
somewhat error prone. Most of the time you have to tweak the colors,
especially the deep blues. It is somewhat unavoidable when you map a
additive colorsystem to a subtractive colorsystem. Maybe others might
have a commandline hack for you.

HTH,
   M.E.Farmer



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