Your favorite Rocket Gang Secret Mecha.
You will need the following software installed on your personal computer:
scanner_refl_fix- https://github.com/doug3236/scanner_refl_fix- referred to as "srf" throughout
- have fun compiling this from source on a non-Windows machine
- ArgyllCMS - https://argyllcms.com/
oxipng- https://github.com/shssoichiro/oxipng
You will also need some color profiles. For working spaces we're using https://github.com/ellelstone/elles_icc_profiles/tree/master/profiles because they are well-behaved and it's easy to see how these were created. You will need a scanner profile (aka input profile), which is particular to your device (and which was generated with a target image that was first processed with srf prior to creating the profile). You will need the sRGB profile, which is included in Elle's profiles as well as ArgyllCMS; however, I am choosing to use the sRGB that is included on Windows/Mac by default, since that is what most other folks have (even though it's not well-behaved).
Lastly, you will need a checkerboard calibration grid. For < 1 pixel of error on the features, scanning at 1600 dpi, you likely would want something with < 15.875 μm tolerance. I used the WMT-127-3.0-C grid from Dot Vision.
Just press the scan button on your scanner and it makes the picture, idk what you need all this stuff for. 🙃
IT IS VERY IMPORTANT THAT THE INPUT TIFF BE TAGGED WITH ITS CORRECT DPI, since srf needs to know the physical size of the image to work! Epson Scan will tag the image correctly, and image editors like Affinity Photo & Photoshop will preserve any DPI that's been set, so as long as you didn't do something like bring the scan into a project with different DPI, you should be fine here.
(TODO)
- If you don't have a calibration grid, you'd skip the camera calibration step entirely. When centering you'd use the same edge and corner-detection logic, only the destination points for the corners would be four points that you choose, based on the era of card you are scanning.
- srf can be omitted.
This means libtiff found some metadata it didn't understand; however, it will just get ignored. This won't affect the files you're generating in any way and you can just ignore this warning.