02-09-2023, 01:13 AM
Not much to add, but making measurements on a scanned image is fraught with peril. Scanners can have a transversal distortion(*)
that can amount to around 1% along the right edge. You should scan a sheet of squared paper and check that all the transverse spacing is as regular in your image (once loaded in Gimp) as your original paper.
The whole story.
A possible fix.
(*) Because the sensor isn't physically as wide as the scan bed. So there is the equivalent of a wide angle lens in front of it. The other direction (scan head travel) is usually fine.
that can amount to around 1% along the right edge. You should scan a sheet of squared paper and check that all the transverse spacing is as regular in your image (once loaded in Gimp) as your original paper.
The whole story.
A possible fix.
(*) Because the sensor isn't physically as wide as the scan bed. So there is the equivalent of a wide angle lens in front of it. The other direction (scan head travel) is usually fine.