I have scanned many pages on a scanner with scan type set to 300 dpi black and white text and output format set to PDF. Unfortunately, a great deal of the pages were from a book and there is a shadow on the scanned pages. I wonder if there is any possibility to make the black area (which I marked with blue stripes below) automatically, with a function in Adobe PDF or any other software, white. In the red circle below, there is some text that spans from the black to the white background. This text I would like to be all black and appear on white background.