Nesta Dorrance, 74, whose Jefferson Place Gallery was a premier Washington showcase for contemporary artists such as Sam Gilliam, Gene Davis, Rockne Krebs, Willem de Looper, Howard Mehring and Tom Downing, died of a heart attack Dec. 14 at a London hospital.

A force on the local art scene in the 1960s and 1970s, Mrs. Dorrance helped secure the reputations of young artists now considered masters of their form. She also piqued the interest of a rather stodgy Washington establishment in the burgeoning world of artistic expression.

Artists of the period were escaping the boundaries of hard-edge painting to experiment with plastics and other nontraditional media; Jefferson Place was often the first to show this new and sometimes puzzling work.

Mrs. Dorrance took on the management of a cooperative gallery that had been founded several years earlier by artists largely connected to American University: Ben Summerford, Robert Gates, Helene Herzbrun, William Calfee and Mary Orwen. Its first director was Alice Denney, who went on to found the Washington Project for the Arts.

The Jefferson Place Gallery moved in 1962 to P Street NW, then becoming a major art corridor in the city. The gallery featured the work of newcomers Mrs. Dorrance considered promising, as well as of established local artists such as Jacob Kainen.

Mrs. Dorrance was known for her intense preparation for shows, repainting the gallery walls herself to provide a pristine background or taking as much care with the work of relatively unknown artists as she did with the draped hanging works of Sam Gilliam or the striped color paintings of Gene Davis. She also was among the first dealers to show the work of local photographers, who had had few local venues in the city until then.

Mrs. Dorrance gained a reputation for her sure eye and readiness to show adventurous art, including laser pieces and other experimental work. The Welsh-born art dealer was herself a popular fixture, elegant and tall, with red hair and a fashion model's sense of style. Openings of shows at the gallery were social events that drew a range of personalities.

What made the Jefferson Place unusual, sculptor Rockne Krebs said in an earlier interview, was the consideration Mrs. Dorrance extended to her artists. "She never told you that your work was too experimental," he said. "She focused on the artists of this city--and she stuck with them."

After moving in 1972 to a more expensive location on P Street, however, the gallery began to founder. Mrs. Dorrance blamed the state of the economy, saying it had discouraged art buying. In debt to her artists and unable to meet the rent, Mrs. Dorrance closed Jefferson Place in 1974. She said she hadn't been tough enough about holding down expenses.

Mrs. Dorrance's interest in art began when she was attending the London School of Economics and exploring the museums of the city. She moved to Washington in 1951 when her then-husband took a job with the International Monetary Fund, and she took up the study of painting and drawing at American University. She rarely exhibited her own work.

After the gallery closed, she continued to work in the art business and was a consultant. On several occasions in later years, nostalgic shows were organized by artists she had represented and helped promote during her gallery's heyday. She moved back to London four years ago.

Her marriage to Graeme Dorrance ended in divorce.

Survivors include a daughter, medical researcher Deborah Dorrance of London, and three grandchildren.

CAPTION: Nesta Dorrance, shown in 1986, drew crowds to her art gallery.