THE UNIQUE CANCELLATION PROOF.
This lithograph was published by legendary art dealer and print publisher Wolfgang Ketterer. After his printer had finished printing the edition of a lithograph, Ketterer would have him cancel the stone with a large X and then print a single proof to guarantee that no further uncanceled proofs could be printed. Ketterer kept such cancellation proofs for himself; they rarely appear on the market.
Printed on extremely fine wove paper.