What is a collector's mark?
 
A collector's mark is everything affixed to a print or drawing that indicates an ownership or provenance. Marks are ink-stamped, blind-stamped or hand-written (paraph, number or inscription) on the recto or verso of a work or art, or on the mount. The mount itself may serve also as a sort of collector's mark.
 
Collectors' marks are applied by collectors, agents, heirs, executors and museums to affirm ownership or the inclusion in a sale of the studio of a deceased artist.
 
As an example we reproduce here the stamp of Frits Lugt (FL), published under Lugt number 1028, as well as the stamp of the Fondation Custodia (FC), that has not yet been published.