I read somewhere where it said that it helps to turn the autograph upside down an ALSO examine the autograph from that angle also- Do you all think that this holds water??
I think the idea is to compare it to real exemplars that are also upside down. Probably not necessary for routine items with low risk, but if you have a suspect item, it provides another angle of attack. It's possible your eyes may pick up on something they may miss looking at it the "normal" way.