"Welcome to an experiment," says anchorman Robert MacNeil on "The Brand New Illustrated Journal of the Arts" (9:30 on Channel 26), a two-hour survey that may be either a one-shot special or the first of a series, depending on audience reaction.

Theoretically, there are no unsuccessful experiments; you learn at least what not to do the next time. So this experiment may be a success, if the producers keep on trying until they get it right. And they should; arts are (next only to politics and the economy) what is happening most spectacularly in the United States. Americans spend more on the arts than on sports -- enormously more if you include (as this program does) publishing, movies and pop music, and television needs a sort of "Wide World of Arts."

But "TBNIJA," in its first tentative installment, falls sadly short. Its most glaring problem is that it somehow manages to give the impression that arts are something done by foreigners and imported by Americans -- even pop music, represented by Bob Marley singing with subtitles! When it shows Americans succeeding in the arts, they are usually overseas: Amanda McKerrow in Moscow, jazz players on a tour of China. What is happening in this country? A tour by the Netherlands Dance Theatre, a British production of "Nicholas Nickleby," French and Polish films by Abel Gance and Andrzej Wajda, the appointment of (Romanian) director Liviu Ciulei to the Tyrone Guthrie theater in Minneapolis and -- coming soon -- Andrew Lloyd Webber's new musical, "Cats," which opened in London last spring.

Visual arts are represented by the works of dead foreigners (Picasso's "Guernica," the Rodin exhibit at the National Gallery and five masterpieces stolen in recent years), or by oversized cartoons done by living artists: an interview with Roy Lichtenstein ("It's not meant to be profound") and another with British painter Beryl Cook ("I must say I like bright colors"), whose work looks something like colored Esquire cartoons of the 1930s.

Why not a bit of "Satyaghara" or "Willie Stark" or "Pennies From Heaven" or any of the hundreds of interesting new things being done by Americans in America? Why is classical music represented entirely by Andre'-Michel Schub winning the Van Cliburn competition? Why are dozens of significant events boiled down to simple-minded headlines flashed on the screen: "ROME: 1800 year old statue victim of air pollution . . . USA: Aboriginal artists tour the country . . . Earthquake damages the Parthenon . . . Ormandy hands baton to Muti." Lack of time and budget is one answer. There is also the tangle of union rules that limit television's access to live performing arts in this country, and perhaps a fear of apparent favoritism: If you show the Houston Grand Opera, you may offend Dallas. Answers to these problems must be found if "TBNIJA" is to become what it should be and what the country needs.