This PDF containing a circular gradient, produced using scribus:
Looks like this when rendered with evince 0.8.1 (using poppler 0.5.4, all from debian sid):
I.e., there are horrible aliasing/moire patterns.
When rendered with xpdf (v3.02), the result is beautiful and clean:
Spot checks reveal that it also looks perfect in Adobe Reader on Win32 and OSX, and Preview.app on OSX.
In case it is useful for some reason, I also put up the scribus source file:
(In real life this arose with the background of a presentation I wanted to give via PDF. Unfortunately, the talk is insufficiently psychedelic to live up to this background.)
I can confirm the problem with evince (libpoppler 0.5.4, Ubuntu feisty, i386) and that it looks fine with xpdf 3.02. It also looks fine with ghostscript (gs 8.54).
This may be related to #10942
*** This bug has been marked as a duplicate of bug 10942 ***