Pretty cool tech. I helped my dad experiment with stitching his artwork but he eventually decided to rely on a Betterlight scan back for a large format camera.

The inventor of the Betterlight made limited number of the devices with an experimental large format CCD made by (Nikon? Canon?). He since passed away and there's a small community of owners desperate to keep their scanners operable, it's a near exinct tech. They allow for ~500 megapixel scans of artwork.

By placing studio lights above, shooting down, we capture the shadow and relief of the paint.