To determine the value of a signed and numbered print, take into account factors such as the artist, the age of the print and the edition. The most valuable prints tend to be from small print runs by highly sough-after artists.
A limited-edition print differs from an open-edition print in that only a small number of prints are produced before the original plate is destroyed or defaced. Limited-edition prints are usually more valuable than open-edition prints due to their rarity. The smaller a print run, the more valuable the prints may be.
The quality of a print may also affect its value. In small print runs, for example, of 75 to 100 prints, the print quality doesn't tend to noticeably degrade. In larger print runs, the earlier prints may be more highly valued because the plate starts to wear down after many uses.
Limited-edition prints are usually marked with a ratio - the first number indicates the edition while the second number indicates the total print run. For example, a print marked "2/200" is the second edition produced out of a 200-print run. Such a early edition may be more valuable than one marked, for example, "183/200." A limited-edition print is also likely to be more valuable if it is sold with a certificate of authenticity from the artist.