A small, distinctive mark, sometimes embossed and usually composed of initials, often found on prints and drawings. A ‘studio stamp’ was applied to materials sold from an artist's studio after his death. If the stamp is impressed on the sheet without ink it is known as a ‘blind stamp’. Prints and drawings in private collections have also often been given a stamp known as a collector's mark. In the later 19th century facsimiles of artists' signatures were sometimes printed on drawings as a form of studio stamp.