How to convert yellow background from the scanned images of a complete book

Question

I am having a pdf file having approx 500 pages, it is having scanned images of all the pages. the gound of these pages are yellow due to very old book, i want to remove this yellow ground from all the pages in one go, please guide me. i am using CS6 standard.

Answer 1

You would have to open the pages one at a time using File --> Open and then use the adjustment tools. If you use e.g. the Levels adjustment's whitepoint eyedropper, this could be as easy as one click. You would then save each adjusted imaghe separately and then later re-assemble them using Acrobat or similar tools to create a new PDF. Generally there could be a million pitfalls here, though, such as:
the scans being inconsitent and thus each adjustment looking different
the adjustments being too agressive and eroding the text
the adjustments requiring lots of manual intervention
additional cloning and painting being required to remove stains or fix holes
In any case, it's not going to happen "in one go", no matter what. You will have to spend considerable time on this if you want to do it right. Perhaps you can extract the pages by using File --> Save Pages as Images in Acrobat and then batch process them, but beyond that I don't see muich in the way of automating or streamlining the process. This is something one typically would do already when scanning the books by using a color chart and a high quality scanner that can calibrate itself based on this reference chart for each page...
Mylenium