I have scans of some very old books that I would like to have printed out for my use (they are out of copyright), but because the pages are yellowed from age, the printouts have a grey background.
The scans are in PDF format, and I cannot request a re-scan in black and white. I cannot convert the text alone, as this book features illustrations on every page which are intertwined with the text. And the fix cannot be a print function fix, as I will be uploading the file to have it printed in book form.
I have tried several different methods: I downloaded a free trial of Pitstop Pro and used that to try and replace the yellow color with white, but because the pages are so many different shades of yellow/brown, I was getting pages with splotchy whitish areas...and no amount of fiddling with it would bring it to anything approaching all white.
I tried doing the same thing after converting it to Device grey, but the same thing happened. I couldn't get rid of all the grey.
So then I tried sending it through Photoshop and running a threshold filter on it. This helped, but the file was so unbelievably huge when I was done that I couldn't use it. I tried to reduce file size in Acrobat, but it did very little good.
Is there any way of solving this within Adobe Acrobat 9 Pro? Or of using Photoshop without the file size ballooning out of control?