But What Does It Mean?

Etchings and lithographs usually have a series of markings and numbers on them, but what exactly do these mean?
AP - this mark stands for "Artist's Proof", a few prints that the artist might make for his own collections or to finalize color choices and double-check registration marks.
Edition - the total number of prints made of an image. The print will usually be marked with two numbers separated with a slash, such as "12/35". The first number represents the print's place in the series, the second number represents the total number of prints in the edition.
Limited Edition - some artists produce only a certain number of prints and then destroy the plate used. Purchasing a piece from a limited edition is best.
Signed and numbered - an artist will sign each piece in pencil and attach an edition number. The print's number should not affect its quality although some people like to purchase pieces with low edition numbers.
State - while the artist is pulling proofs of a print, he may make alterations which change the plate. Each time a plate is changed, it is said to be in a "state."