I had a manual for an assembler (Laser Genius on the C64) that used the opposite approach: the text was black but the pages were a deep red, which would theoretically photocopy to black.

In practice the original was about as much a pain to read as the photocopy.

EDIT: I remember the letters in the copy having a sort of lighter colour halo around them, which made it readable. I figured was due to the blackness of the letters pulling the limited amount of toner towards them...