Bug - Acrobat Preflight Fixup Transparency Flattening introduces extreme JPG artifacts
When using the Flatten Transparency Preflight Fixup, transparent images that are flattened are heavily compressed, introducing extreme JPG artifacts and banding in smooth gradients.
This does not match flattening out of Indesign or Illustrator or using the Flattener in the Acrobat Print Production tools. We would expect to get the same results with the Preflight fixup that would be produced with other flattening methods.
See attached with examples of original unflattened art, art flattened with Acrobat Print Production and Acrobat Preflight fixup.
Preflight produces a severely degraded image with visible banding and large artifacts that aren't visible on the other two blends.
Produced using Mac OS X, and Acrobat DC and XI. Source files came from Illustrator CC 2017 and InDesign CC 2014.
PDFs were exported as PDF X4 if left unflattened when PDF was made or PDF X1a if flattened during PDF generation out of the source application.
Thanks for reporting the issue. Our team is looking into it.