Question

I’m trying to use PDFTK to rotate pages in my PDF document. Executing something like the following should result in no changes to the page rotation:

pdftk in.pdf cat 1N output out.pdf

(This is rotating page 1 “north” or “0 degrees.”)

In some PDF test documents, it works as expected (meaning, no changes to the page occurs). However, on some test documents, the PDF document is rotated 90 degrees. An additional 90 degrees is consistently applied to any page rotation I attempt to do. So, if I do this:

pdftk in.pdf cat 1E output out.pdf

(This is rotating page 1 “east” or “90 degrees.”) The result is the page is rotated 180 degrees — an additional 90 degrees!

The PDF looks OK when viewed in Acrobat Reader.

The only difference with these problem test PDF documents is that I used Acrobat Pro to already change their rotation. When applying PDFTK page roation on these already rotated PDF documents, I run into this problem.

Any idea what’s going on?

Answer 1

When you use the “normal” rotation parameters (N, E, S, W), you are setting the rotation flag on the PDF pages to your parameter (e.g. 90 degrees). This does not take into account the current rotation setting. Here is the paragraph from the pdftk documentation about rotation:

The page rotation setting can cause pdftk to rotate pages and
documents. Each option sets the page rotation as follows (in
degrees): N: 0, E: 90, S: 180, W: 270, L: -90, R: +90, D:
+180. L, R, and D make relative adjustments to a page’s rotation.

In addition to the NESW rotation settings, you also have the L, R and D options, that allow you to make relative adjustments that take the current rotation flag into account.

If that does not solve your problem, I would need access to a couple of test documents (one that does work correctly, and one that results in the wrong rotation setting).