" To be sure, the Professional Photographers of America (PPA) has gone to great lengths to guard against copyright infringement -- much to the benefit of all photographers.
We all should take reasonable care to let others know that our work is valuable and especially whose work it is.
Normally, people frame their pictures, mounting them on mat board. The color of the mat board is the maker's choice and should complement the print; in competition, however, many judges demand that the maker use white mat board.
STAMPING IT IN FIVE DIFFERENT PLACES IS PARANOID AND JUST PLAIN NUTS!!
Last week at a photography meeting another professional went on at length about the methods he uses to "ensure someone won't steal his work!!
In that respect, make sure any sales receipts you use, note that "the work entitled ______, sold herewith, is protected under federal law and copyrighted by ______ on _______ with registration pending.
This work may only be displayed for personal use and not duplicated or published in any form absent the express written consent of the author (you)." Got it?
If you blow your signature with ink, you need to replace the matt. As far as registration protection, on the back of the print, place your copyright notice.