Flattening of transparent layers when converting PDF to PDF/A-1a

Technical Support
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1

Product: Server SDK

Product Version: 11.8.1

Flattening of transparent layers when converting PDF to PDF/A-1a

PDF/A-1a requires any transparent layer to be flatten during the conversion and the
resulting file may have graphical artifacts because of it.

Below is the first page of an PDF file with gradient transparency. Original file to the left and after conversion to the right.

There are transparency both at the top of the page and also at the bottom. These seems to be treated differently. A the top the background becomes solid white while at the bottom the transparency is removed.

Is there anyway to control or adjust how the flattening is done?

Flattening
Flattening604Ă—429 81.1 KB

Please provide a link to a minimal sample where the issue is reproducible:
PDF to convert

3

Thank you for contacting us about this. We currently don’t have any API to control how transparency layers are flattened during PDF/A conversion. However, I can get some more information from the team regarding this process. Can you please provide us with the original PDF for further examination?

4

Here is the file

Collectum_2024_Rapport_Mer-_pension_for_pengarna_Sa_bidrar_den_svenska_modellen_till_en_starkare_tjanstepension.pdf (688.6 KB)

5

Thank you for the file. The “layers” are displayed due to the z-order of the items in the content stream. In other words, the PDFs internal structure places the image is “behind” the top section of the page, while “in front” of the bottom left graphic. It is also behind the red triangle area on the bottom right.

PDF/A conversion did not re-order the graphics and image in any way. It only removed the transparency (no flattening was done to this file).

Please let me know if you have any further questions.

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