Bold splashes of black paint or sharp teeth featured prominently in a picture of a vampire can be more than the fanciful product of a child's imagination.

Art therapists are decoding children's art and discovering messages of anger, fear and despair. How children work with art materials -- their use of colors, shapes and placement -- and the subject of their art can help explain why children are aggressive, withdrawn or upset.

Through art, therapists hope to prevent children from developing serious emotional problems. According to Washington art therapist Edna Salant, "Children won't get into delinquency and other more complicated behavior disorders if we help them early and at the time of stress."

While art may be as old as the scratchings of prehistoric cave dwellers, the use of art to diagnose and treat emotional problems has been recongnized professionally only in the last 35 years.

Art has been linked to psychological therapy, because it allows people to cope with feelings which are too overwhelming to communicate in words. As symbolic speech, art is a less threatening and more basic form of expression.

"If you ask a child, 'What's wrong,' he will say, 'Nothing,' said Gilda Grossman, a Toronto art therapist, who met with more than 700 others for a Washington conference of the 10-year-old American Art Therapy Association. w

"But if you give him paint and clay and a trained art therapist, you will find the areas of stress."

Classroom troublemakers, children of divorce, hospital patients, the physically handicapped and all children under stress can benefit from art therapy, say its practitioners who work in a variety of settings, either individually or with a team of therapists. Trials, whether a move to a new neighborhood or a death in the family, are easier when children use art to recognize and accept their feelings.

Billy, for example, was referred to a "spontaneous art class" at his school because he was the class bully. Raised by a succession of housekeepers and a TV set, he expressed his need for emotional nourishment in class sculptures of food and in paintings of over-size breats, said Grossman, who worked with Billy as part of a 10-school project sponsored by the Toronto Art Therapy Institute.

In a family portrait, Billy also revealed his deprivation by drawing his mother without arms, "to show she didn't come through," said Grossman. Billy's aggression decreased, said his therapist, after several months of art therapy.

Jim, another student in the spontaneous art program, was also acting out in class. In a self-portrait he drew himself as a vampire with ferocious teeth. But his hollowed-out sculptures showed he also felt weak and empty, said Grossman.

Another clue to Jim's emotional problem was his drawing of his younger sister as a large potent figure. "In art she assumed her real role as the dominant person who controlled her family," said Grossman.

Simple as it may seem, the interpretation of art symbols is a complicated process which does not rely on set formulas like handwriting analysis and horoscopes.Art therapists, who train in psychology and art for an MA degree, are quick to warn against kitchen diagnoses of children's art.

"Parents shouldn't get alarmed if their child paints in black for a week. Art therapists study a child's behavior and his art and look for recurring patterns. If he paints in black for months, or he repeatedly uses themes of isolation or hostility he could be expressing anxiety," said Grossman.

Sometimes, however, children's art does not have an emotional message. A painting may be nothing more than an exercise in creativity and a child may only be interested in the art materials, his technique and the results of his work. Or art may be a recreational release of energy like bike-riding or a soccer game.

In art therapy the scene is set so the focus is on feelings instead of art process and product. With a low adult-child ratio, the therapist tries to create a permissive environment in which children are accepted and not judged.

When Billy made a clay guillotine and beheaded a figure he indentified as his art therapist, she still smiled and gave him his afternoon's ration of milk and cookies.

"We want to give children a new emotional experience -- a place where it is safe to express their feelings," said Grossman. "All those kids that get kicked out in the hall could be in a spontaneous art room."

In working with preschool children, Salant is usually able to begin therapy before they become candidates for the principal's office. She has worked in schools and hospitals, and most recently as a consultant at the National Child Research Center in Washington.

"Susan, a student at the National Child Research Center, came to me for art therapy right after her parents divorced. Her brother was reacting strongly, but she wouldn't talk about her father's absence. During our sessions, which ranged over six months, she drew a pictorial history of her parents' marriage and separation. Eventually she began talking to her mother about the divorce, and she was a much happier child," said Salant.

Susan's drawings in the sessions, added Salant, were different from her regular art work. "She was very gifted and her drawings were all over the school. But she seemed to know instinctively that our one-to-one session was her time to let out her feelings."

In working with Tommy, a Vietnamese child recently adopted by an American couple, Salant used a combination of art therapy and play therapy.

"He was full of memories of war, violence and destruction. His early pictures always featured helicopters. Time and again he reenacted the bombings with a toy plane and doll house. When the plane hit the house, he grabbed a figure of the mother or father and said, 'He no good,' as if older adults hadn't protected him.

"Tommy had a tremendous amount of anger, frustration and helplessness. But gradually he worked it out. One day when I asked him if he wanted to play with the doll house, he said, 'I'm finished.'"