Several years ago, Andy Warhol sat down and signed his name on copies of the tabloid magazine he edits, Interview. The magazine's regular price is $2; he charged $50 for the signature copies and they went fast. Once again Warhol wanted to demonstrate the gullibility of people -- those who would believe his name had value in and of itself.

Signatures count for a lot in the print market and hundreds of artists have gotten on the bandwagon. Because an artist's name on a print can raise the price by two or three times, they generally view signing and numbering works as a valuable source of income.

This is not to say that a signed print has intrinsic value only to the autograph hound -- many artists and dealers contend that by signing a print the artist endorses it and, implicitly, claims it as his or her own work -- but, in many cases, artists have no more involvement in the technical processes of printmaking than signing them.

In some cases, the sole value of a print is in the signature. Salvador Dali signed blank pieces of paper on which reproductions of his works were to be made. So did Marc Chagall. Picasso's granddaughter, Marina, published a series of the artist's prints on which she signed her name (her signature, it is said, looks remarkably like Picasso's). They sold for $500 each. In these cases, the artists never saw the finished works, but the prints still sell at prices comparable to originals.

"A signature has a certain cachet, and some buyers believe that a work with the artist's name on it has some investment value," says Nicholas Stogdon, former head of the art print department at Christie's auction house.

"The real issue is, however, what kind of print is it and the degree to which the artist was involved in its production. The secondary market -- or 'resale value' -- of most signed prints is poor and Christie's tends to deflect inquiries whenever possible."

An "original print, where the artist himself worked on it," he notes, has a longer lasting value than a "reproduction which the artist did no more than sign." An etching, for instance, requires an artist to make the plate from which impressions are taken. Picasso made several thousand of these.

A lithograph is also viewed as an original work because the artist must draw directly onto the stone. There are also reproductive prints in which an artist or craftsman makes an etching or lithograph from a painting done by someone else. Editions of this kind have been done for a number of major artists, including Raphael and Turner.

A photographic reproduction of a work of art, sometimes called a colotype, is a far more questionable print in terms of its originality. of print -- a product of advanced four-color techniques -- generally has the least direct involvement by the artist, who may or may not be asked to sign and number the prints.

A colotype usually should not cost as much as an etching or lithograph, says Stogdon, "unless you believe there is something magical in the mechanical process."

The tradition of artists signing their prints is less than 100 years old. Artists, such as Toulouse-Lautrec and Pierre Bonnard, signed some -- and not others -- depending on the collectors' wishes. They often signed works as they sold them; those for which there was no demand in the artists' lifetimes went unsigned.

The practice of artists signing all of an edition's prints at one time is believed to date from the 1930s when a Parisian dealer, Leo Spitzer, persuaded a few of the major artists of the day (including Matisse and Picasso) to produce elegant reproductions of their work that they would sign and he would sell.

"A Picasso with a signature may be worth twice as much as one without a signature," says Mark Rosen, head of the print department of Sotheby's, the world's largest auction house, which sells approximately 6,000 prints a year with prices ranging from a few hundred dollars to over $100,000. "Chagall did a series of prints called 'Daphne and Chloe' and those that are signed are worth 10 times as much as those that are unsigned. Otherwise, they are the same prints."

Most artists are well aware that their signatures mean more money for their works. Picasso did one series of etchings in the 1930s called the "Vollard Suite," which he started signing in the 1950s and '60s as a way of increasing contributions for communist causes he championed. Norman Rockwell signed a series of photographic reproductions of his paintings to help support the Cornerhouse Museum in Stockbridge, Mass., which features his paintings. Andrew Wyeth also signed reproductions for fund-raising events.