2009/7/14 Andrea Cappelli <a.cappe...@asidev.com>:
> I'm a beginner with Python and I'm using PIL to convert a lot of images
> from RGB colorspace to CMYK in order to insert them in a catalogue to be
> printed by a typography
>
> i use the following piece of code
>
> handle = PIL.open(filePath).convert("CMYK")
> ## some stuff
> handle.save(newFilePath)
>
> Everything seems ok, except than when I see the generated result (i
> produce a pdf using reportlab) with Acrobat Pro the K layer of my images
> is empty.
>
> Every point of color in CMYK has the K value equal to 0. Seems that PIL
> convert RGB to CMY, ignoring the K value. This is true except for black
> images (RGB=0,0,0), that are mapped to (0,0,0,100)
PIL's default conversion does the simplest thing possible; it doesn't
handle color profiles, undercolor removal, etc. that you need to take
into account if you're doing print stuff. You can use something like
LittleCMS to do a better job (there's a binding included in the
upcoming 1.1.7 release, available from hg.effbot.org and there's at
least two separate Python bindings available as well).
Alternatively, you could embed a color profile in your PDF files and
leave the rest to Acrobat and the printer (I don't know how to do that
with ReportLab, though).
</F>
_______________________________________________
Image-SIG maillist - Image-SIG@python.org
http://mail.python.org/mailman/listinfo/image-sig
