One of this author’s first jobs was scanning film transparencies for a publishing company, and using an early version of Photoshop to edit out the scratches that had been caused by the transparencies having been kept in a shoebox seemingly full of grit. The scanner in question was a large box containing, among other things, a CCD (Charge-Coupled Device) optical sensor. It was slow and fiddly, but in the early 2000s it was still better than the digital cameras of the time.