WHEN ARTISTS talk of productive periods, the idea is that these moments of high inspiration come and go. For Leopold Stokowski, productive periods only came and came and kept on coming. At his death on Tuesday, at age 95, his confidence in his abilities was so strong that he was in the second year of a five-year recording contract. Tireless and seemingly ageless, Mr. Stokowski enlarged the art of symphonic conducting to the point that his interpretations and improvisations of great music achieved a greatnes of their own. Part Olympian and part prima donna (he said early in his career that he ought to be paid at least as much as Babe Ruth or Jack Dempsey), Mr. Stokowski became a worldwide figure through the universality of music. From his first time on the podium - while conducting a children's orchestra in London at age 12 - till his last, he gave more than 7,000 performances.

Mr. Stokowski's earliest achievement was to bring a burst of culture to Philadelphia. From 1912 to 1937 he led the Philadelphia Orchestra, introducing spectacular premiers. Too proud to repeat the same old numbers and too daring not to be challenged by the opportunity to create masterpieces, Mr. Stokowski drew to the concert hall audiences that previously had paid no attention to, let alone much money for, symphonies. In a newly published book on Mr. Stokowski. Paul Robinson writes: "His concerts were often like dramatic events with musical accompaniment . . . Stokowski had shown that he could reach people, particulary people who knew nothing about classical music."

Critics said that reaching instinct got the better of Mr. Stokowski when he went to Hollywood in 1936 to make movies. Although the sight (in "100 Men and a Girl") of the dignified condutor trying to bring out the best in Adolph Menjou in the trombone section was perhaps closer to a comic opera than a symphony, Mr. Stokowski later joined with Walt Disney to produce "Fantasia." It is one of Hollywood's most enduring films, based on music from Beethoven, Bach, Tchaikovsky and Musorgski among others.

Mr. Stokowski's innovations - some of them bold, some of them whimsical - often drew criticism. But throughout his career, his passionate committment was to elevating music. He not only accomplished that. In the process he also lifted the spirits of millions of listeners.