Phony Money

Here's Paul looking at the counterfeit bill...
 

and Perry examining the plate. It's easy to see that there's no way that
bill was printed from this plate. Worst of all, everything reads right! A
proper printing plate would be a mirror image of that which it prints.

Roger Kirk points out that, if the plate were used in an offset printing
press, the image on the plate would not be reversed! Reversal of the
image is done in the printing process. Go here to learn more.

Charles Richmond reports that, at one point in the episode, Barry
Davis makes a pencil rubbing of the plate on a sheet of paper (see
below) giving us more evidence that the plate is not reversed.

[Trivia][Perry Mason TV Series]