How do I prevent resolution loss when I resave a pdf file after editing in photoshop?

Question

I have a created a 50 page pdf file. I want to put the word SAMPLE across the middle in large letters at 50 percent opacity.
But when I re-save the page (as a single page, as pdf) the file loses resolution.
Is there any way to prevent this? I am working in A4

Thank you!

Answer 1

First of all you didn’t told if you have the source document which you created that PDF file from it or not and I hope you created it with Adobe Acrobat Pro and not other third-party softwares.

If you have it yet the best way (professional way) for creating a PDF file is using a PostScript printer. You don’t need have that printer in real world. Just install a free driver for your desired printer (must be PostScript) in your Windows.

Now inside the software creating your document, put the preferred Watermark on the all pages and save it. Now print it with the installed PostScript Driver.
After processing the print through the source software which you created that 50 pages document, you will get a file with PS extension. Give it to your Acrobat Distiller and make sure choosing the Setting as “Print” or even “Press Quality”. Your file quality will be perfect.

Answer 2

In Adobe Acrobat (version 6), under Edit and Preferences, change the settings at which the image types are compessed.