please add support for automatically or manually triggered white balance compensation

[rpodgorny]

i often scan under artificial light and it would be nice to automatically do the white balance compensation so that white is actually white in the final document

[pynicolas]

Could you please provide a photo? That would really help understand your use case.
You can get the last captured image from the "About" screen (tap "Report a problem with last captured image").

As of today, FairScan uses white balance only to detect whether a document should be processed as a grayscale document.

[rpodgorny]

Scan 2026-04-23 17.18.12.pdf

Scan 2026-04-23 17.17.54.pdf

Scan 2026-04-23 17.16.55 (1).pdf

Scan 2026-04-23 17.16.55.pdf

[rpodgorny]

the ones with yellow-ish tint are scanned under artificial "warm white" light source. the ones with blue-ish tint are scanned with just ambient sun light.

[pynicolas]

Thanks a lot. That clarifies the problem.

FairScan's goal is to get PDFs automatically, not to give a long list of tools to manually adjust PDFs (see https://fairscan.org/blog/fairscan-purpose/). So I'm very open to discuss what can be done automatically, and much more reluctant to add a "manual" adjustment.

I guess that your PDFs show very well the challenge: some look doable and others are very tricky. How to know automatically what should Scan 2026-04-23 17.16.55.pdf look like without seeing Scan 2026-04-23 17.16.55 (1).pdf? How to "improve" most images without degrading too many? I will think about it, but I can't say I have an easy solution.

[rpodgorny]

i totally get it. that's why i called it "manually triggered", not "manual". i suppose there would be no settings or slider or anything. it should "just work" when triggered. but it should probably not be automatically applied to all scans as it could lead to weird results in some cases (that's why i attached the tricky ones would probably fail on "most common" setting).

[rpodgorny]

maybe it could be triggered automatically only for "something on white page" type of scans which i guess shouldn't be that hard to detect.