Elaine Sweet Horwitch always threw a great party, but her final blowout was unusual, partly because it was so dignified and certainly because it took place without much notice.

Stunned by the sudden death of the gallery owner whose name has long been synonymous with Scottsdale, about 1,000 people last week filed into Scottsdale Center for the Arts for a funeral service more solemn than any previous gathering at which Horwitch was the center.

A lot of the bereaved were artists and would have worn black anyway, even if they hadn't been headed for a wake. They stared sadly at the casket on the auditorium stage, the one swathed in a bright, folk-art quilt that was Horwitch's last flea-market find. They stood around in the lobby afterward, the men in pleated pants and ponytails. Stood around on the cusp of a new age of art in Arizona, one that had begun before Horwitch died but is far more noticeable because she's gone. Stood around talking about "the end of an era."

They may have suspected the era was ending last year, when Marilyn Butler, who opened her gallery in 1978, closed her doors, a victim of the art recession and a venture in Santa Monica that failed. They knew for sure now that Horwitch, who brought together a stable of artists that included Merrill Mahaffey, Anne Coe, Bill Schenck and others who became identified with the "Southwestern style," was also out of the picture.

Over the past year, they had seen Horwitch revamping her gallery's focus and had known something was up.

"Even if Elaine hadn't passed away, there were definitely big changes coming in the Scottsdale art scene," says Julie Sasse, administrative director for Horwitch's galleries. "What used to be in the area is now completely changed."

The "area" she refers to is Marshall Way, the short stretch of pavement lying just north of Indian School Road that, on Thursday nights during the season, is the heart of the opening-night soirees known to their stylish devotees as Art Walks. Marshall Way is probably the center of contemporary art in Scottsdale, where Horwitch and galleries like Lisa Sette and The Hand and the Spirit share the block with Udinotti, C.G. Rein and newcomer Bentley Tomlinson.

Of these, Horwitch, Sette and The Hand and the Spirit have been the most progressive and well-regarded--although there are also numerous art aficionados who have never considered "progressive" Horwitch's fondness for primary-color cacti on canvas, contemporary takes on Native American jewelry and painted wooden coyotes that howl at the sky. These experts have called Horwitch's approach to art "kitsch." "She was not about serious art dealing with overall important issues," says gallery owner Sette, who since the mid-Eighties has mounted elegantly spare shows of cutting-edge art across the street from Horwitch. "She showed things that were funky and colorful and fun."

But if Horwitch was viewed askance by the experts, her influence over the development of Valley art at its best, as it is today, cannot be overestimated. Together with Suzanne Brown, she upgraded Valley tastes and made "contemporary" a palatable word among local collectors whose previous tastes in art had run to realistic paintings of horses. "She probably paved the way for me to be here," says Sette.

She also became a wildly colorful Valley fixture, a respectable grandmother who packed a gun, collected motorcycles and staged celebrations at unlikely moments. (Julie Sasse remembers climbing onto the roof of Horwitch's house with her boss on a night when it was publicized that escaped convicts were loose in the neighborhood. Horwitch brought with her a supply of fried chicken, cherry pie, binoculars and weapons. She devotedly scanned the environs and waved gaily to police helicopters strobing above her. She transformed a prison break into a party.)

She was the woman of enthusiasm and savvy who was at the heart of the most prosperous period of art the state has ever experienced, a period when the work of "Southwestern style" artists--and even unknowns--was sold almost as soon as it was mounted on the walls. "It was like a check-out at K mart," says Sasse.

That period is dead now, and Horwitch, too, and some onlookers have only noticed the one because of the other. Julie Sasse recounts another quintessential Elaine Horwitch story:

"A drunken guy had staggered in the front door of the Santa Fe gallery and was standing in the window, among some carved bear fetishes. He picked up one and put it inside of his shirt. Someone in the gallery yelled, `Stop that man, he's stealing something!'

Elaine said, `Who's stealing? I'll stop him!' And she goes up to him with her gun drawn. She says, `You're under arrest.' And the guy peed in his pants. She wasn't afraid of anything."