... just my two cents
dude, just my two cents... although the idea sounds cool for busy artist, but, i really don't think the signature is the way to stop scummy sh#t copy others' art work, it's the law and system that fails artists.
put it this way, we often see people (obviously) copy other's art work and some even makes good profit, but most of them often get away from such crime pretty easily... as long as they made minor changes, with few tough lawyers to back them up.
in order to protect artists and their art work, we must improve the current system, get rid of the copy-shit (so call "copycat", but they bring shame to the name of this beautiful animal, therefore, i preferred to call them "copyshit") once and for all~~ #=_=.
Cheers, and happy painting.
i want to improve... please teach me!