Avoid hidden text

[Ellen Marie]

We sometimes get PDFs with hidden information which makes remediating very challenging.  How does this information get into the PDF?  What can be tell our submitters to avoid getting this hidden information?  I have acrobat XI.  thanks in advance for your help.

[olafdruemmer]

There are many ways how page content may be present on a PDF page but may not be visible. It could be covered by some other object, it could be clipped (for example, only a part of an imported image or graphic file is left visible), it could be set to a color or a transparency setting that make it impossible to perceive it on a given background (for example white object on white background, or black text on top of a rectangle filled with black). Very often this is an unintended side effect of how the page was put together in the authoring application. In some cases it could be intentional (for example a serial number or other type of ID in white text directly on the page background that could be retrieved by a program but should on purpose not be visible to a user looking at a rendered display of the page).

In any case - it should be safe to mark anything as an Artifact that is not visible to a sighted user when looking at the page on screen or at a printout of the page.

[Ellen Marie]

Thanks, olafdruemmer. But we want not to get this hidden information in the first place. Is there something our submitters can do so we don't get it?

[olafdruemmer]

Without any infomation about how these files get created (and/or without providing sample files) it is almost impossible to say anything meaningful...

[Ellen Marie]

Just as I thought.  Thanks for getting back to me.

[Joel Geraci · Accepted solution]

You say you have Acrobat XI but not whether it's Standard or Pro.

With Pro, you can select "Sanitize Document" to remove all hidden information which would include white on white text and black on black text as well as a bunch of other hidden stuff. It's in either Protection or Redaction, I can't remember which at the moment.

Standard does not have that feature.

[Ellen Marie]

Thanks, Joel.  I have XI pro.  Because I post these documents to post on the web, I don't want to take liberties in inadvertently removing any of the submitter's information.  And we don't have the original documents, so I don't have any idea how the hidden information got there.

[Joel Geraci]

You have two options then.

1) Have your submitters run the "Sanitize" process which would involve them subscribing to Acrobat Pro DC... which you might not be able to enforce. Or...

2) Take the liberties.

[Ellen Marie]

OK.  Thanks!  I'll run that past management.