A memorial celebration is planned for Florence Wysinger "Flo" Allen, a legendary San Francisco artist's model who posed for virtually every prominent West Coast painter of the past half century. Ms. Allen died June 1 at her sister's home in El Sobrante. She was 84. Born in Oakland in 1913 and educated at Fremont High School, she started her modeling career in 1933. At the 1939 World's Fair on Treasure Island, she had a booth on the Gay Way, a small show called Candid Camera. "They'd come in and we'd have this little drape going, and they'd snap, snap," she told The Chronicle in 1978. The few remaining photographs from that period, some of which are still considered highly provocative, are now coveted collectors' items. Ms. Allen has been drawn, sketched, painted and sculpted by five decades of artists who make up a Who's Who of modern art: Diego Rivera, Mark Rothko, Elmer Bischoff, Hassel Smith, Roy De Forest, Ralph Du Casse, Wayne Thiebaud, Eleanor Dickenson, Beth Van Heusen, Mark Adams, Richard Shaw, Nathan Oliveira, Karl Kasten, Glenn Wessells, Helen Salz, Art Grant, Joan Brown, Frank Lobdell and Bill Wiley. Du Casse, who taught painting at the San Francisco Art Institute, the University of California at Berkeley and Mills College, called Ms. Allen "not only a superb model, but a remarkable personality and an inspiration to the students." She modeled at the Art Institute, the California College of Arts & Crafts and the art departments at UC Berkeley, Stanford and Mills, among many others. She was a fixture on the local art scene until 1987, when she was struck by a truck while crossing a street in Fisherman's Wharf. She broke both legs, severely restricting her mobility in her later years. Last October, the San Francisco Art Institute held a tribute to Ms. Allen, and hundreds of alumni, collectors and luminaries of the San Francisco art world turned out to honor her. Her figure and animated face made her so recognizable that in 1965, when a 30-year retrospective of works by well-known artists was held at the UC Medical Center Millberry Union -- all with images of Ms. Allen as the model -- the show was heralded as "a history of local art in her time." She was so much in demand as an artist's model that in her "retirement" she became coordinator of models at the California College of Arts and Crafts in Oakland. She also taught a course for prospective models, sharing some of the tricks of her trade. "There's an art to this business," she used to say, savoring the pun. "There's a hell of a lot more to it than skin and bones. It's very difficult work. You find muscles you didn't know you had. Just when you think you're relaxed, the sweat starts running -- and then you itch. The strain is tremendous." Ms. Allen once explained in an interview with The Chronicle that while "many models are natural exhibitionists with highly developed egos," her own reason for joining the profession years ago was "mainly economic -- I liked to eat." She always preferred to model nude because, she explained, "you can't think with your clothes on." Besides, when she started, the going rate was 50 percent higher for nude modeling than for clothed -- 75 cents an hour compared to 50 cents an hour. It was largely through her efforts that the pay improved for artist's models, after she founded the Models Guild in 1945, a craft union that still exists. She used to tell her students that the key to successful modeling is knowing "your body from stem to stern." She did not want modeling students who either had been or wanted to be fashion models. "I shudder when they call," she used to say. "This is with clothes off, baby -- there's a big difference. Besides, the (art) students don't like the pretty, skinny ones. Artists prefer their models to have a lot of stuff on them." Experience in the porn trade was also a no-no. "There's an old saying about female models," she explained. "Some pose rose and some sunflower. When they pose sunflower, I don't need them. You don't show off all your wares, you know." Ms. Allen was also a fixture in North Beach for her other career. After working all day as an artist's model, she put in many a long night's work as a hostess in several well-known North Beach restaurants -- including the Old Spaghetti Factory on Green Street, the Savoy Tivoli on Grant Avenue and the Washington Square Bar and Grill. Ms. Allen is survived by two sisters, Ambrosia Wysinger Jones of Oakland and Edna Wysinger Black of El Sobrante, and numerous nieces and nephews. A celebration of her life is being planned for September at the San Francisco Art Institute. In 1955, she donated her papers to the national collections of the Archives of American Art at the Smithsonian Institution. Contributions may be made in her memory to the Archives of American Art, West Coast Regional Center, 1151 Oxford Road, San Marino, CA 91108.