Home/ Questions/Q 8077789
In Process

The Archive Base Latest Questions

Editorial Team
  • 0
Asked: 2026-06-05T15:34:55+00:00

I am having some problems with the PDF files that I make using the

  • 0

I am having some problems with the PDF files that I make using the PDFSharp library. The files are ok as long as I am viewing them normally.

However I need these files to be changed using the accessibility options (Edit -> Preferences -> Accessibility (in the left menu Categories) -> Report Document Colors -> Custom Color). Whenever there is image with transperancy and/or transparent masks and the Background color is set to black everything disappears.

I looked at the PDFSharp code and it seems that they are setting some transparent SMask, which I did not find to do anything noticeable (at least for me), but I am not sure if I disable it will it screw up something that I cannot think of.

Most probably I won’t get help on this one, but I hope that someone knows something more about this problem with PDF Transparency and the Accessibility options.

Share

Leave an answer

You must login to add an answer.

Need An Account,

1 Answer

  1. Editorial Team

    The transparency mask is created for images with transparency only.

    So if your images contain black lines and a transparent background and you change the color of PDF pages to black, you will see black lines on a black background – you will see nothing.

    If your images contain black lines on a white background, you will see your image as you know it: black lines on a white background.

    Transparency is a feature, it’s optional.

    Maybe there’s a bug in PDFsharp. If I watch the output of the Graphics sample with black background color, pages 4 and 5 are completely black (looks wrong to me).
    The output of the Hello MigraDoc sample looks correct to me. The image on page 1 does not use transparency and keeps it white background, the chart on page 6 is transparent (which leads to black lines on a black background).
    But maybe that’s a bug in Adobe Reader – everything looks fine if I do not set a background color, but activate the transparency grid instead.

    If you think that your images do not contain transparency, then we’ll need files (PDF and image) for further examination.

    Edit: I just checked the output of the Graphics sample with Adobe Acrobat 5 – all pages display correctly even with black background color. With Adobe Acrobat 8 and Adobe Reader X pages 4 and 5 are black. Looks like a bug in Adobe Acrobat/Reader to me.

    • 0