Flip dozens of PDFs horizontally

Question

Let's say 100 PDFs each 5 pages long so about 500 pages.

This is my current method. It's quite tedious:

1. Turn PDF into image with online free converter
2. In MS paint, flip them all horizontally
3. Convert the pictures back to PDF

So basically the letters and numbers on every page are backwards.

What's a better way?

Flipping horizontally is not a rotation unless my understanding geometry is wrong. So unfortunately, I can't just highlight the pictures in the file explorer and do rotate horizontally.

I use Windows 10.

Answer 1

ImageMagick convert can do this for you provided GhostScript is also installed on your system by reading the .pdf file, for each page generating an image, flipping it horizontally using flop, and adding it to an output pdf file. You will have to read the documentation play with the settings a bit to get what you need.

• Free, gratis & open source
• cross platform
• callable from a batch file.

Assuming that your pdfs are all in a single directory and you need them in a subdirectory called flopped, (that already exists), you can do:

FOR %a in (*.pdf) DO convert %a -flop flopped\%a

If you were to wish to do this from a batch file you would need to double all of the % signs. See also this page for how to do for loops so as to preserve file names.

Tested on Windows 10.

You will notice that your pdf files will usually get bigger - this is because the existing "draw this text" commands in the pdf can't be used with backwards text.