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+--- Thread: How can I improve text on a yellowed/blotched page? (/Thread-How-can-I-improve-text-on-a-yellowed-blotched-page)
How can I improve text on a yellowed/blotched page? - j4nd3r53n - 01-10-2022
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.
[attachment=7335]
RE: How can I improve text on a yellowed/blotched page? - Redraw - 01-11-2022
(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
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.
RE: How can I improve text on a yellowed/blotched page? - denzjos - 01-11-2022
That's what I did. G'Mic-Qt / Repair / Ian Noise Reduction 2019 (set all sliders to the right), then 'Colours / Desaturate / Mono Mixer' (use the sliders for the best result) and then 'Filters /Enhance / Sharpen (Unsharp mask)'. Then you cab use 'Colours / Curves to optimise (use a S-form curve). As Redraw mentioned, use always a black paper under the page to scan. Click on the picture for the original format.
[attachment=7339]
RE: How can I improve text on a yellowed/blotched page? - Ofnuts - 01-11-2022
A very simple Color ➤ Desaturate ➤ Desaturate followed by a contrast increase:
[attachment=7340]
Side note: next time, but something dark under the page before taking a photo, this avoids the print on the other side to show through.
RE: How can I improve text on a yellowed/blotched page? - j4nd3r53n - 01-11-2022
Wow, thanks to everybody for the good answers; this really helps!