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deirdreh50297859
Participating Frequently
January 20, 2017
Answered

Transparency effects of graphics not rendering in PDF Reader for Android

  • January 20, 2017
  • 1 reply
  • 8079 views

I am creating a document in InDesign that uses graphic transparency effects. When exporting as a PDF (for client review), the transparency effects render correctly when viewing the PDF on desktop version of Reader, but not on Reader on Android device (Note 3). Is this a limitation of mobile Reader app? Is it an Android limitation? I have not tried opening the PDF on other mobile devices. 

This topic has been closed for replies.
Correct answer Dov Isaacs

Files downloaded and analysis completed!!

Your PDF file doesn't contain any transparency whatsoever. It is a PDF/X-1a 2001 file based on PDF 1.3. Neither PDF 1.3 nor PDF/X-1a support “live transparency” (or for that matter ICC color management or many other modern PDF attributes).

I will assume that your original InDesign document indeed did use live transparency. But when you export to PDF/X-1a (or any version of PDF less than PDF 1.4), all transparency must be flattened into opaque objects. In this case, the simple transparency you used in the InDesign document is emulated via use of Overprint. (Overprint is not considered best practice for modern PDF publishing workflows!) You can readily see what is going on using the Output Preview tool of Acrobat Pro.

Unfortunately, very few PDF readers support display of overprint. Although Adobe Reader and Acrobat support full and proper display of overprint if you have the correct preferences and modes set, neither the iOS nor the Android Adobe Acrobat Mobile products support display of overprint; the overprint attribute is effectively ignored and you end up with the visual anomalies you originally described and that appear in the screen shot you provided. I personally do not know of any mobile PDF readers, including those provided by Apple in iOS or Google in Android that support overprint display.

Workaround? Ditch use of PDF/X-1a which depends on overprint for emulating some transparency effects when PDF is created with flattening. Our recommendation is to export PDF/X-4, a much more modern standard that fully supports live transparency and color management. With any halfway modern RIP or DFE for printing, content that originally contained transparency will render/print better and faster with PDF/X-4 with live transparency maintaining until the RIP process where transparency blending and color management occur than with PDF/X-1a with pre-flattened transparency (which can yield weird stitching and flattening artifacts. The live transparency in such PDF/X-4 files will also display without problems in all Adobe desktop and mobile Acrobat / Reader versions as well as many third party PDF viewers.

Let us know if you have further questions and enjoy the rest of your weekend.

          - Dov

1 reply

Dov Isaacs
Dov Isaacs
Braniac
January 21, 2017

The Android and iOS Acrobat Reader versions fully implement the PDF transparency model. They don't implement ICC color management at this time and that may be the cause of what you are seeing. If you could post a sample file of what you are encountering, we can validate what is going on here at Adobe.

          - Dov

- Dov Isaacs, former Adobe Principal Scientist (April 30, 1990 - May 30, 2021)
D
deirdreh50297859Author
Participating Frequently
January 22, 2017

Hi Dov,

Thanks for you reply.

Here is the generated PDF, that is rendering transparency properly (overprint effect) on my Acrobat desktop app:

Dropbox - report_cover.pdf

Here is a screen grab of the same PDF on my Android device, Reader app:

https://www.dropbox.com/s/8er813r5mmjipvx/Screenshot_2017-01-22-00-57-02.jpg?dl=0

Dov Isaacs
Dov IsaacsCorrect answer
Braniac
January 22, 2017

Files downloaded and analysis completed!!

Your PDF file doesn't contain any transparency whatsoever. It is a PDF/X-1a 2001 file based on PDF 1.3. Neither PDF 1.3 nor PDF/X-1a support “live transparency” (or for that matter ICC color management or many other modern PDF attributes).

I will assume that your original InDesign document indeed did use live transparency. But when you export to PDF/X-1a (or any version of PDF less than PDF 1.4), all transparency must be flattened into opaque objects. In this case, the simple transparency you used in the InDesign document is emulated via use of Overprint. (Overprint is not considered best practice for modern PDF publishing workflows!) You can readily see what is going on using the Output Preview tool of Acrobat Pro.

Unfortunately, very few PDF readers support display of overprint. Although Adobe Reader and Acrobat support full and proper display of overprint if you have the correct preferences and modes set, neither the iOS nor the Android Adobe Acrobat Mobile products support display of overprint; the overprint attribute is effectively ignored and you end up with the visual anomalies you originally described and that appear in the screen shot you provided. I personally do not know of any mobile PDF readers, including those provided by Apple in iOS or Google in Android that support overprint display.

Workaround? Ditch use of PDF/X-1a which depends on overprint for emulating some transparency effects when PDF is created with flattening. Our recommendation is to export PDF/X-4, a much more modern standard that fully supports live transparency and color management. With any halfway modern RIP or DFE for printing, content that originally contained transparency will render/print better and faster with PDF/X-4 with live transparency maintaining until the RIP process where transparency blending and color management occur than with PDF/X-1a with pre-flattened transparency (which can yield weird stitching and flattening artifacts. The live transparency in such PDF/X-4 files will also display without problems in all Adobe desktop and mobile Acrobat / Reader versions as well as many third party PDF viewers.

Let us know if you have further questions and enjoy the rest of your weekend.

          - Dov

- Dov Isaacs, former Adobe Principal Scientist (April 30, 1990 - May 30, 2021)
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