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I have imaged scanned in 600 dpi. The paper is old, specially designed, with visible texture and tiny colourful fibers being part of its structure. I'd like to "extract" image from it. Removing texture is not a problem - I achieved that with color curves option. But these colour fibers still remain. How can I get rid of them?

The problem is that I try to "clean" copperplate graphics so I don't want to remove subtle lines of drawing itself. Which filter or tool should I use?

I'm using Linux and GIMP but if you have the tips for other software (Photoshop etc.), just share your thoughts, please.

I attach two images - first is raw scan, next is the image without paper texture but with fibers still visible.

Raw scan

Partially cleaned scan

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In GIMP (or equivalent), you could:

  1. Convert image to 1-bit black & white (Image > Mode > Indexed...)
  2. Convert image back to RGB (Image > Mode > RGB)
  3. Apply some low-pass filter to smooth out the edges (Filters > Blur > ...)

Here's the result with 1 iteration of the Mean Curvature Blur filter in step 3, applied directly to the raw scan:

Binarized and blurred

It's not perfect, but perhaps useful as a first approximation.

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  • 1
    Yes, this is definitely good solution as a first step/approximation. Thin subtle strokes in the drawing dissapear but I'll try to play with parameters and filters. Thank you! PS. If someone has another solution, I'll be thankful!
    – stalker
    Oct 8 '20 at 20:18
  • 1
    1+2 can be replaced by Color>Desaturate.
    – xenoid
    Oct 9 '20 at 20:40

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