I've really badly scanned document in PDF which I would like to enhance (make grey, hardly visible invoice readable). Is there some free tool, or trial tool that I could use on this one document? OS is Windows.
13.5k 19 19 gold badges 89 89 silver badges 118 118 bronze badges asked May 16, 2011 at 18:46 2,861 3 3 gold badges 25 25 silver badges 28 28 bronze badgesTake a screenshot of it by Alt + PrtScr and paste it in IrfanView
Then go to the menu "Image" and apply "sharpen" ( or press Shift + s ) until you achieve the result you need.
answered May 16, 2011 at 18:53 791 6 6 silver badges 16 16 bronze badges I tried both Shift + S and Shift + U and it seems Shift + U did it better. Tnx! Commented May 16, 2011 at 19:38Cheapest would be to convert the pdf to an image. If you can fit the whole document on your screen without scrolling, just take a screenshot. Then use Irfanview or similar to adjust contrast and brightness to improve the file.
PDFs are not images per se, and so you cannot generally modify them, even with the full-blown pdf apps, like you would images, which is what you are trying to do in this process.