Any possibility of adjusting contrast in PDF file? - Adobe Acrobat Macintosh

[Mary_Gilmore@adobeforums.com]

I scanned a document directly to PDF format. Unfortunately, the blacks aren't quite black enough - sort of a medium-ish grey. The scanner I used doesn't have any control over the density of the scan (long story, will explain if anyone is remotely interested).

Anyway, I know I can open PDF files in Photoshop and adjust contrast there, but this is a 70-page document. Obviously not a practical solution.

Does anyone know of a method that I can perhaps darken up my blacks? I'm using Acrobat 6 Pro and didn't find any joy there. Any third-party products out there?

Thanks in advance.

[Unregistered]

I scanned a document directly to PDF format. Unfortunately, the blacks aren't quite black enough - sort of a medium-ish grey. The scanner I used doesn't have any control over the density of the scan (long story, will explain if anyone is remotely interested).

Anyway, I know I can open PDF files in Photoshop and adjust contrast there, but this is a 70-page document. Obviously not a practical solution.

Does anyone know of a method that I can perhaps darken up my blacks? I'm using Acrobat 6 Pro and didn't find any joy there. Any third-party products out there?

Thanks in advance.

On a Mac I use the ColorSync Utility (>application>utilities). Open the pdf doc and use the "lightness decrease" filter. I had to apply the filter twice to get the best results, works like a charm.
good luck Bart

[Unregistered]

well, It was a question for me for a while but finally I found the answer.
for doing so you should download 2 programs (I did so):
1- nitro pro or acrobat reader pro (just download a free trial one)
2-Advanced Tiff editor (download free trial)
after installing them:
-if your pdf file has less than 100 pages ,all you need to do is opening it in Tiff editor
and then selecting all the pages and at last going to Tools>Color adjust and performing your desired contrast.
-notice that Advanced Tiff editor can't process if the pdf file itself has too many pages so if pdf is a big one ,before the step discussed above, you have to extract pdf to 2 or more parts, for example a 200 page pdf=2 * 100 page pdf and subsequently doing that instruction for both 2 parts and after all combining the parts with a PDF pro software.