[Image-SIG] Problem when resizing large JPEG to thumbnail

[Fredrik Lundh]

On Mon, Sep 28, 2009 at 5:01 PM, Etienne Desautels <tiit at sympatico.ca> wrote:

>>> 3. Converting from TIFF CMYK to RGB shift the colors dramatically.
>>
>> This is a bug in 1.1.6 and earlier (well, strictly speaking, it's a
>> old bug in Photoshop, but I guess we're not really in a position to
>> make them change their implementation ;-).  It's fixed in 1.1.7.
>> There's also a drop-in replacement JPEG plugin by Kevin Cazabon that
>> fixes this for earlier versions (in a somewhat roundabout way, due to
>> a bug in the core library that has also been fixed in 1.1.7); see:
>>
>>   http://mail.python.org/pipermail/image-sig/2006-April/003871.html
>
> I saw some threads about this bug but I was with the impression that applied
> only to the JPEG plugin, not to the CMYK support in general ?

Oh, sorry - misread your question.  Yes, bad colour shifts are quite
common if you use the default approximation (which doesn't take the
colour profile into account).  For better results, you want PIL 1.1.7
with littlecms and the ImagingCMS module (see the list archives for
pointers to the development repo).

</F>