09-27-2022, 06:15 AM
You can use a layer mask to blend the two layers progressively over the width of the overlap.
A possibly easier solution is to not use Gimp but a panorama app such as Hugin. These usually have an option (Parallel scan or whatever) to stitch pictures where the camera/scanner has been translated (instead of rotated like in usual panorama). This will do both the alignment and the luminosity/color adjustments. Rickk'ss remarks still apply though, the scanner will often distort the edge to the right so you can 1) test you scanner and 2) cut out the bad parts before submitting to Hugin.
A possibly easier solution is to not use Gimp but a panorama app such as Hugin. These usually have an option (Parallel scan or whatever) to stitch pictures where the camera/scanner has been translated (instead of rotated like in usual panorama). This will do both the alignment and the luminosity/color adjustments. Rickk'ss remarks still apply though, the scanner will often distort the edge to the right so you can 1) test you scanner and 2) cut out the bad parts before submitting to Hugin.