There is no lack of art in the world of stamp collecting. Beyond the art that goes into producing stamps with meaning and eye appeal, there are stamps that are directly connected to artists, whether by reproduction of their work or that produced specifically for the stamp.
Stamp collectors can begin at the Art Nouveau movement of the 1800's, when Czech Alphonse Mucha was one of the premier artist/illustrators. While he is well known for his poster ad illustrations, often featuring beautiful women, flowers and serpentine flowing lines, less well known are his contributions to philately.
While his poster designs were reproduced on postcards that are now worth many hundred of dollars, it was his design that graced early Czechoslovakian stamps, as well as other issues of the country.
Mucha may have been the first fine artist to have his work disseminated through the mails in such quantity: For a couple years his were the only stamps to appear on Czech mail.
Sometimes an artist's work can be appropriated to good philatelic effect, like the Picasso doves that appear on stamps of China. Picasso's work has been widely adapted to stamps, with his anti-war painting Guernica reproduced on stamps of a number of countries, most meaningfully Spain, site of the attack which the artist portrayed with stunning impact.
American Artwork and Artists on Stamps
American artist Robert Indiana is best known for his Love sculpture, an iconographic work of art that helps define the late 1960's/70's in America. One variation of it is on display at the Penn State campus in Philadelphia. The stamp was the first in the continuing series of Love stamps.
Another one shot artist, adapted to philately from an earlier day is Whistler, whose iconic Mother's Day portrait found its way to a stamp in 1934.
An artist of the modern era, Peter Max, has supplied collectors with colorful examples of his art, including the U.S. Expo 74 stamp as well as various UN issues.
Edward Hopper's sailing painting The Long Leg is the 2011 stamp issue for the American Treasures series honoring art, artists and crafts. It is unusual in that Hopper is associated mostly with dark moods and settings, like Early Sunday Morning. Perhaps his most iconic painting is Nighthawks, which shows an atmospherically lighted diner and its nocturnal transient denizens.
In Beyond The Perf, the USPS publication, it was stated that the American Treasures series exists to "...give joy from something beautiful on an envelope." Other great American artists who can be found in the American Treasures include John James Audubon, Mary Cassatt, Louis Comfort Tiffany, and Winslow Homer.
Rockwell's Philatelic Art
Norman Rockwell is in a class by himself as an American illustrator and artist. If popularity is the name of the game, in terms of US artistic interest there are probably none that can touch the artist of Americana, Norman Rockwell. Stamps with his work, include The Four Freedoms, City Mail Delivery, Boy Scouts of America, Tom Sawyer and Self-Portrait.
From his American history oriented cachets like Washington crossing the Delaware; to a series commemorating the Boy Scouts of America; to iconographic Saturday Evening Post covers as cachets, Rockwell is the American artist that rules the U.S. stamp and cover world.
If one can judge by sheer numbers of covers and stamps featuring an artist's work it would appear that the people have chosen Rockwell as the artist of choice.
A Few Last Words on Art Stamps
Like any other popular topic on stamps those who decide to collect art on stamps must decide what their limit is. The area is so popular that there are many out to take advantage of the collector with issues of less than legitimate standing. And even among legitimate offerings there are so many that a healthy bank account is necessary to put together an acceptable collection.
There are stamps - labels really - that are not connected to any philatelic agency and are issued by those who know that some topical collectors are happy to pay for items that look like stamps and feature their topics. Stamps with the names of small islands where no one lives are not legitimate. Also, the Sand Dunes countries have always printed stamps featuring classic artworks that may be very pretty, but have about as much relation to being stamps - i.e. used for the purpose of carrying mail - as a three dollar bill does to currency.