I have many of the French art stamps, larger sizes, vert. and hori..  These are from the 1970 thereabouts.  Monet, Degas etc.......  Why haven't these appreciated very much?  I have mounted 50 in a frame to enjoy them.  Just returned from a vacation trip to France and I purchased the crystal mounts and solventless adhesive in Rouen at a stamp shop.  Was not the reason to go to France.