WASHINGTON is enjoying its big art boom. But some of its artists are not. More and more of them are complaining that it can be weeks, months or even years before they are paid. Sometimes they're never paid at all.

"It's just plain crazy," says sculptor-painter-printmaker Mildred Thompson, one of several artists currently having trouble collecting from the Premiere Gallery in Bethesda. "I pay for the materials, a place to work and the dealer's commission, and now I have to pay a lawyer to collect my money!"

"I don't think there's any dealer who hasn't been in a financial bind at one time or another, and it's no fun," says Henrietta Ehrsam of Henry Gallery, one of dozens of dealers in town who has put off paying her artists from time to time.

"It's not a nice story, but it's true," agrees dealer Diane Brown, emphatically excluding herself.

"Dealers all have trouble paying their artists," says dealer Chris Middendorf. "Even big-name dealers have had periods when the artists carried the gallery."

One result is that more and more artist-owned co-ops and alternative spaces have been created in recent years to serve thousands of emerging artists who have neither the organization, the disposition nor the means to do battle with errant dealers. Places like Washington Project for the Arts and the Washington Women's Art Center, now celebrating its best places in town to hunt and find new talent.

Another result is a new legal activism among the city's artists. Attorney Joshua Kaufman, founder of the Washington Lawyers Committee for the Arts, says that "the tide is changing, and artists more and more are demanding their rights."

Nonpayment problems happen "regularly in the art business because -- unlike any other -- it runs on a word and a handshake," says Kaufman, whose group was created in 1976 to help indigent artists, defined by law as those who earn less than a total of $7,000 a year.

"But it's not because dealers have larceny in their hearts," he says. "Galleries are usually small, under-capitalized businesses with low cash-flow problems, and they use the available cash to pay the landlord, light and heat first -- usually out of funds due the artist. Artists are particularly susceptible because they tend to be passive about enforcing their rights for fear they'll be dropped."

He might be added that the artists with the big reputations are usually paid first. Often, it simply has to be that way: The big-sellers bring in the gallery's bread-and-butter (along with customers for new artists). Dealers therefore do what they must to hang onto them, and that includes paying on time. Dealers have also been known to dole out cash to help artist-in-need, particularly those they believe in. Artists, however, generally prefer to complain. It goes with the territory.

Printmaker Ann Zahn fought with two local galleries over nonpayment, and finally solved her problem the same way many other artists have: by joining an artist-owned co-op, in her case, Studio Gallery. "I may not sell much, but when I do, I know I'll get paid."

Some prefer to fight before they switch. "What amazes me is the apathy of the artists," says Diane LaTorre, who threatened to take a Chevy Chase commerical gallery to court for nonpayment. With the help of a lawyer who took one-third of the settlement as his fee (such contingency cases are frequent) she made an out-of-court settlement, recovering about $200 before the fee. LaTorre has also taken the new route: "I now show only in nonprofit gallaries like Emerson in McLean and at WPA which not only gives you a contract, but pays immediately."

Mildred Thompson, who is currently battling Premiere, is an accomplished artist who came to Washington as artist-in-residence at Howard University three years ago after several successful years in Germany. Lured back to an American art scene she had rejected 10 years earlier, she decided to go public with her complaint against Premiere Gallery after the gallery's checks began to bounce.

"I think I can make it here," exulted Thompson just a year ago, after a show at Premiere netted her $11,400, which the gallery promised to pay in 12 monthly payments of $950 each. It issued her 12 post-dated checks, and Thompson found that she could pay the rent on her vast studio space on Bladensburg Road and live very nicely on that income.

The trouble began when the last three checks began bouncing. "I went to a lawyer, but when bills began to mount, I couldn't afford it," says Thompson, who has appealed to a consumer-help TV program. Meanwhile, she has sublet her studio starting in November, and will go back to Europe, possibly for good. "I could have made it, but I didn't count on not getting paid."

Lyn Beatty, owner of Premiere, claims that Thompson has failed to take into consideration the gallery's financial problems and the large investment that was made in Thompson's show. "I could have declared bankruptcy in April, but I decided to hang in," says Beatty, who agrees that she still owes Thompson -- but feels that the artist doesn't realize what an investment the gallery had made in her. "I never pay framing for an artist, or for costs of printing and mailing, but I did in this case because Mildred had no money. oI think she's making a mistake to make such a big fuss about this," says Beatty. "Mildred got a tremendous amount of publicity out of that show. I wanted to keep her going and I did, and I don't regret it."

"There's always been a problem where new or lesser-known artists are concerned," says Jack Rasmussen, who admits to owing veteran painter Robert Gates a considerable sum after a successful recent show of his work. But Rasmussen is paying the artist 10 percent interest on what he owes -- a most unusual situation. Rasmussen, who deals almost exclusively in lesser-knowns of all ages, believes that cash-flow problems are inevitable. Dealers and artists, he says, have "always had a symbiotic relationship. It just won't work any other way."

That's the consensus. "Everybody in the art world complains about not being paid, including the dealers" says Chris Middendorf, pointing out that purchasers often pay over a long period of time, and that most galleries can't afford to pay their artists until full payment has been received.

Some dealers, like Harry Lunn, keep the handful of young artists they show on a monthly stipend. Relative newcomer Manfred Baumgartner also has his artists on either a stipend or an annual guarantee.

"We have different arrangements with different artists," says Middendorf, "but if I could, I'd have them all on stipends." But new talent, he says, is unprofitable for at least five years. "It costs $20,000 a month to run a major gallery here," he says, "and that's always there, whether a show sells or not.

"So when we show a new artist like Stephen Ludlum, whose paintings sell for $1200, we get $600 for each one we sell retail. Or $350 if we sell through a consultant who takes 20 percent. If you sell to a collector who wants a 10 percent discount, you only get $480. At that rate, you can sell out his shows and lose your shirt."

Attorney Joshua Kaufman recommends that artists get written contracts and warns them against leaving works on consigment for months. "If an artist doesn't police his own work, and the galleries don't see him, they'll forget about him.

"Overall, the artist has an affirmative obligation to look out for his own interest. In addition to filing security agreements [to prevent confiscation of the art by creditors if a gallery should fail], he should keep track of what's been sold and the terms of purchase. In the contracts we write for artists, we also insist that the gallery guarantee the credit of the customer. After all, the buyer's credit is not the artist's problem.

"Unfortunately, these aren't the sort of things that are discussed when you have the handshake, oral agreement -- and that's the custom of this trade. It clearly works to the artist's detriment.

Says Premiere's Lyn Beatty. "Now I know why dealers would rather do business with dead artists."