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JPEG compression mangles png image

We have a document that has a PNG image used in the header. When JPEG compression is selected it mangles the image in the header when saved as PDF.



I have included a program that I used to do a quick test of both PDF and PDF/A 1-b as well as the original RTF document and the output PDFs for with and without JPEG compression and PDF and PDF/A. The results for compression are different for PDF vs. PDF/A. The PNG has a transparency set and like PDF/A is turning it to black where PDF is setting it to white.

Hi Scott

Thanks for your inquiry. We have tested the scenario and have managed to reproduce the same issue at our side. For the sake of correction, we have logged this problem in our issue tracking system as WORDSNET-13146. You will be notified via this forum thread once this issue is resolved.

We apologize for your inconvenience.

Hi Scott

Thanks for your patience. You are facing this issue because PDF/A-1 doesn't actually support the transparency.

Currently for Flate compression we use a "hack" which gives a good output in this case (blend transparent image with white background). We could implement the same "hack" for JPEG compression too. Please let us know if you want use to implement this feature.
The hack is better then what we have and it will be consistent so that will be a yes for implementing the hack for JPEG compression. I was surprised to find out PDF/A didn't support transparency, but I also realize that PDF/A was about preserving primarily government documents, not making them look fancy.

Thanks for the update.
Hi Scott

Thanks for your feedback. We will inform you via this forum thread once this new feature is available. Please let us know if you have any more queries.

The issues you have found earlier (filed as WORDSNET-13146) have been fixed in this .NET update and this Java update.


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