How can I improve text on a yellowed/blotched page?

[Redraw]

(01-10-2022, 06:49 PM)j4nd3r53n Wrote: I am working on scanning some historical texts, in Chinese - unfortunately the pages are somewhat yellowed and blotched, like the one attached. Is there a easy way to make the background paler - or even completely white - while preserving or darkening the ? I'm preparing the photo for OCR; so far I have only managed to digitalize a minor part of the text.

Hello j4nd3r53n

To get this far use the Curve tool to a loose S shape try different amounts suits you best


then remove the yellow patches with the Hue Saturation tool click on yellow, reduce amount of saturation to -100  and turn up lightness to +100

might  need to redo the curve tool to increase the clarity of black print on white page.

well that's one way
also a suggestion
when scanning place a piece of black card or plastic  under  on top behind   the page to be scanned this can do wonders for removing the text on the other side that shows thru best results are with card and print same colour.


Hope this helps
Regards
Redraw

edit - looking at this again I should have increased the darkness of the black print when using the curve tool second time around um yeahup.