PDF Editing Need

[Tom AZ]

I've been looking for a PDF editor that can adjust the Brightness and/or Contrast of an existing PDF page (in other words, the ability to make it lighter or darker). I really don't even know that this type of thing exists -- just hopeful, I guess.

[Corona]

I'm so glad this was posted in the Lounge. I needed the laugh.

 

But really, I don't know if such a monster exists. If "Mr. Photoshop" Adobe PDF or Adobe Reader doesn't have that feature, what other non-graphic-based clone would even attempt such a thing.

[Andavari]

I've never heard of such a thing not even in Abloate Acrobat Reader, however the first thing that comes to mind is perhaps adjusting your monitor instead. Of course that would be a bit of a pain, but if software can't do it hardware (monitor) very easily can and has had that ability for years.

[Tom AZ]

I've never heard of such a thing not even in Abloate Acrobat Reader

I haven't either -- but it's not really a monitor issue. I have some fairly large, important, multi-page black & white pdf text documents in which the text image density on a few of the pages is not consistent with the other pages. These are documents that get used -- and printed repeatedly. Therefore, I was hoping to standardize the image density from page to page by selectively adjusting those pages in question. I figured this was probably a long-shot -- but I thought I'd ask anyway.

[hazelnut]

Does gamma correction do this on text ??

[Andavari]

I haven't either -- but it's not really a monitor issue.

I misunderstood you then.

 

Have you tried another PDF viewing software, just out of curiosity to see if it's just an issue with one over another?

 

I know I've had issues with Foxit Reader before making some PDF documents look like gibberish, so if you're using it perhaps you have one of those PDF's that cause it.

[Tom AZ]

Does gamma correction do this on text ??

Not sure. I wondered if something like that might work. I'll have to investigate a little further.

[Tom AZ]

Have you tried another PDF viewing software, just out of curiosity to see if it's just an issue with one over another?

I've already checked that out. It's not the viewer -- it's the pdf's themselves. Probably goes back to the source originals -- there must have been some problems at that level. Just thought they might be able to be corrected "after-the-fact."

[MikeW]

You could convert your PDF back to a text document (Big choice here) http://www.pdftoall.com/

reformat your text and then convert back to PDF if you need

[Keithuk]

Tom why don't you use PDF2Word to convert your PDF files to Word documents. I've been using it for a few years its great. The newer v3.0 is a bit slower on converting large PDF files whereas the earlier versions v1.4 used to convert to an RTF file very quickly then you opened that with Word and changed it to a doc file.

 

http://www.verypdf.com/pdf2word/index.html

[JBinarao]

I'm guessing that the source of the PDF file that needs to be adjusted did not originate from a word processor file that was converted to PDF, but rather it was a scanned document saved as a PDF. My experience with PDF files is that brightness and contrast are actually not PDF attributes in the same way that say bookmarks and encryption are, but rather are more image file attributes, such as JPG and TIF.

 

Most scanned PDF documents are an image file (TIF) surrounded by a PDF wrapper, and that's what makes this operation challenging. The PDF would need to be converted to an image file, and then brightness and contrast could be adjusted using an image editor. I like to use Paint.NET for image editing. The file could then be converted back to a PDF using something such as a PDF virtual printer.

 

I am currently not aware of a single program that can do all of this in a few easy steps. I realize this doesn't help the immediate need, but I have found that the best time to handle PDF image quality is during the actual scanning process before the files are actually saved as PDF because it is at that time that image correction is the easiest to control. Otherwise, it's a pain in the rump to fix later.

[Tom AZ]

I'm guessing that the source of the PDF file that needs to be adjusted did not originate from a word processor file that was converted to PDF, but rather it was a scanned document saved as a PDF.

You are exactly correct -- they are scanned PDFs. Your suggestions are well-taken -- and pretty much what I thought from the beginning. However, right now, it sounds like a whole lot more work than I'm willing to undertake. I thought maybe (at least I was hoping ) there might be a simple one-step solution. Thanks for the help.