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+--- Thread: Removing unwanted color, make just b & w (/Thread-Removing-unwanted-color-make-just-b-w--7409)
Removing unwanted color, make just b & w - carljong - 10-28-2022
Attached is an admittedly bad scan of sheet music. It is not being recognized by my piano notation software.
I'm familiar with Colors > Curves to clean up sheet music, but it is not working on this photo.
I saw Despeckle, but the only effect it seems to have is to make things worse.
I wish I could just capture a sample of the bad section, say "this is the pattern", and get rid of it.
Thanks
RE: Removing unwanted color, make just b & w - rich2005 - 10-28-2022
The 'noise' is much the same size as some of the notation, I do think it will ever be wonderful.
A reasonable result of your example using Filters -> Enhance -> Noise Reduction and a bit of smoothing with Filters -> Blur -> Median Blur with radius = 1
[attachment=8919]
RE: Removing unwanted color, make just b & w - Kevin - 10-28-2022
The problem is the noise in your image is all black, so curves won't work.
I did the Nose Reduction as per rich2005, and as that's made the noise into grey then used a curves adjustment to loose the noise:
[attachment=8920]
RE: Removing unwanted color, make just b & w - denzjos - 10-28-2022
Another workflow :
- G'Mic-Qt / Black&White / Stamp (just move the 'Smooth' slider to the right until the dots disappear,value 1.26)
- G'Mic-Qt / Repair / Smooth (NL-Means)
[attachment=8922]
- Optimise with gimp 'Filters / Enhance /Sharpen (Unsharp Mask)'
[attachment=8923]
RE: Removing unwanted color, make just b & w - sallyanne - 10-31-2022
Try G'MIC's repair scanned document (under repair) - doesn't get rid of all the black dots but does most
[attachment=8943]
RE: Removing unwanted color, make just b & w - rich2005 - 10-31-2022
@denzjos @sallyanne
the gimp-gmic-qt plugin is a great tool for this.
However the OP is using MacOS and therefore unlikely to have gmic
RE: Removing unwanted color, make just b & w - denzjos - 11-01-2022
(10-31-2022, 02:09 PM)rich2005 Wrote: @denzjos @sallyanne
the gimp-gmic-qt plugin is a great tool for this.
However the OP is using MacOS and therefore unlikely to have gmic
Okay, I'll keep it in mind.