2009/3/2 David Berthelot <d_berthe...@yahoo.com>: > I ran into a similar problems with CMYK and I think it's because libjpeg > doesn't interpret the CMYK data correctly (possibly stripping a color > profile). This is easily verified using libjpeg standalone tools (like > jpegtran that you can compile when compiling libjpeg).
The problem is probably that Photoshop does not follow the spec and for some reason writes CMYK JPEGs with inverted inks. Sadly there's not a (as far as I know) 100% way to spot Photoshop CMYK JPEGs. If you think you might have a P/shop CMYK JPEG, you need to do 255-r, 255-g, 255-b, 255-k after loading it. Here's a previous thread on the issue: http://aspn.activestate.com/ASPN/Mail/Message/image-sig/3110476 > On the other hand, using ImageMagick python bindings (PythonMagick) worked > fine (I assume ImageMagick doesn't rely on libjpeg). IM does use libjpeg, but it guesses that if there's an Adobe app marker it should invert inks. I don't think this is foolproof though. John _______________________________________________ Image-SIG maillist - Image-SIG@python.org http://mail.python.org/mailman/listinfo/image-sig
