11-11-2019, 10:21 AM
The image is RGB (not indexed) with 256 colours.
The black lines have some white gaps in them. These are probably best fixed in the scanning process. Try and get light areas to scan as black.
In Gimp, I tried 3 different methods. In the image:
Top Left: Original
Top Right: Filters > Genric > Erode
Bottom Left: Select the black with a high threshold. (I used 120.) Grow the selection by 1. Bucket Fill with black.
Bottom Right: G'MIC has a filter Repair Scanned Document.
The black lines have some white gaps in them. These are probably best fixed in the scanning process. Try and get light areas to scan as black.
In Gimp, I tried 3 different methods. In the image:
Top Left: Original
Top Right: Filters > Genric > Erode
Bottom Left: Select the black with a high threshold. (I used 120.) Grow the selection by 1. Bucket Fill with black.
Bottom Right: G'MIC has a filter Repair Scanned Document.