My comic is only sketched traditionally, then made digitally, but here's a big tip. Scanners can suck REALLY bad. Mine is an HP Deskjet and the scanner isn't an exact A4, it eats up colors(so I have to do it all with at least a strong pencil and watercolors are 50/50 on looking good) and also gets randomly dark even if I adjust the plastic cover as best as I can. It also needs the HP app to scan multiple pictures, which crashes all the time, to the point I lost 50 frames of an animation project for no fault of my own and start over from the start, saving and clearing every 10 pages instead.
Test out how your scanner does its thing before diving in with a comic method or a type of varnish, it can help out a lot in the long run.