Twin Cities artist Richard F. Lack, who launched a national renaissance in traditional drawing and painting, died Tuesday at Methodist Hospital in St. Louis Park from complications due to pneumonia. He was 81 and lived in Minnetonka.

The death was announced Wednesday by family members.

Known for his warm, dignified portraits, floral still lifes and landscapes, Lack was a champion of old-school artistic values -- illusionistic perspective, accurate modeling and naturalistic color -- at a time when avant-garde iconoclasm dominated the art world.

His portrait commissions included six members of the Kennedy family, Minnesota governors Wendell Anderson and Albert Quie, as well as prominent Minneapolis businessmen and educators. One of his most enjoyable commissions came in 1989 from the future Earl of Wilmot, an Englishman who provided Lack and his wife, Katherine, with a chauffeur and lodging for two months in the Wilmots' London townhouse while Lack painted Diana, the earl's young wife.

"At first I was a little uneasy," Lack told his biographer, because Wilmot ancestors had been painted by Sir Joshua Reynolds and Sir Godfrey Kneller, two of the greatest portraitists of the 18th century. But the portrait was a success and "we were quite pampered," he said.

In the Twin Cities, he is best known as the founder of Atelier Lack, a studio-school he ran in the Hennepin-Lake neighborhood from 1969 until his retirement in 1992. Modeled on 19th-century French academic principles combined with Boston-style impressionism, the school offers a four-year program of day and evening classes in figure studies, portraiture, color theory and anatomy. It is now run by two former pupils who renamed it the Atelier and moved it to northeast Minneapolis.

"He was a fantastic teacher who gave us the eyes to see and the knowledge, tools and skills to be professional artists," said Stephen Gjertson, a former pupil who taught at Atelier Lack for 16 years and wrote Lack's 2001 biography.

Born March 26, 1928, in Minneapolis, Lack graduated from Roosevelt High School. He studied briefly at the Minneapolis School of Art, now the Minneapolis College of Art and Design, before heading to New York and then Boston in search of more traditional instruction. From 1950 to 1956 he studied with R. H. Ives Gammell, a legendary Boston art educator. During that period he also spent two years in the U.S. Army and met his future wife, Katherine Vietorisz, a Hungarian-born graphic designer and jewelry maker.

Lack exhibited widely throughout the United States, including at the Minneapolis Institute of Arts in 1990 and the Maryhill Museum of Art in Goldendale, Wash., which staged a retrospective in 1988. A prolific writer of reviews and instructional essays, he coined the term "Classical Realism" in 1982 to differentiate his approach from other styles, and helped found the American Society of Classical Realism to further the cause.

His last exhibition, at the Bloomington Art Center in January, included a series of monumental imaginative paintings on Jungian themes that he had worked on for more than 20 years. "He was a seminal force in the revival of interest in academic art, and his paintings have such personal meaning that they will have a lasting influence for years to come," said Gabe Weisberg, a University of Minnesota art history professor.

Besides his wife and daughter, Lack is survived by sons Michael and Peter. Memorial service arrangements are pending.

Mary Abbe • 612-673-4431