When Fay Zetlin first started drawing at age 49, she experienced "the strangest sensation--like an electric current connecting the paper, my hand, my gut, my heart and my brain.

"After 30 years of working at all kinds of jobs including advertising copywriter, book reviewer and medical researcher , I suddenly realized that this was exactly where I was supposed to be." Today Zetlin, 75, is artist-in-residence at Old Dominion University in Norfolk.

Four years ago, she discovered "the artistic delights of color Xerox machines" and renounced the traditional mediums of oil, watercolor and clay in favor of "machine-generated art.

"Right now I'm into microfiche," she says, gesturing toward a wall of abstract prints inspired by ancient symbols and created with modern technology. "By using machines in ways different from what they're intended for, you can produce fascinating images.

"In today's world, art is getting more like science, and science is getting more like art. My message is that time is relative. It changes everything, yet changes nothing. I combine the past and the future to get Now."

Zetlin is one of five practicing older artists whose work is featured in "Patina"--an exhibit named for the mellow beauty that comes with age. First assembled for the 1981 White House Conference on Aging, the show opened last week at the National Council on the Aging's new headquarters in southwest Washington to inaugurate a series of programs highlighting the creative contributions of older men and women.

"We want to illustrate that creativity and talent doesn't necessarily have an age limit," says Jackie Sunderland, director of NCOA's National Center on the Arts and Aging. "Older artists have something quite unique to say to the world. Their work combines imagination and discipline, seasoned technique and fresh insight, plus a terrific store of experiential wisdom."

Studies of "art and aging" indicate, she says, "that creativity and artistic production are sustained, and even increased, in the second half of life. Creative activity directly relates to many developmental needs of the elderly," including communication, conflict resolution, clarification of thoughts and feelings, creation of balance and inner order, a sense of control of the external world and sustaining personal integrity.

"And best of all," Sunderland says, "art is great fun."

Interest in the relationship between creativity and aging has increased, she says, "because as a society we are getting older. One out of every five Americans is currently 55 or older and one in nine is 65 or older. By the year 2030, nearly one out of five people in this country will be 65 or older."

The five older artists featured in "Patina," she says, "offer a very positive side to growing old in a youth-oriented culture." Zetlin was the only exhibitor able to attend last week's opening reception. The other artists are:

* Elizabeth "Grandma" Layton, 73, of Wellsville, Kan., who started drawing intense, extraordinary life scenes in her late sixties as therapy after a 40-year bout with severe depression.

* Lotte Jacobi, 86, an internationally known portrait photographer who made her first picture with a pinhole camera in 1908. She lives and works in Deering, N.H.

* Jacob Lawrence, 65, of Seattle, whose career was launched by a federal arts project during the Depression. Lawrence's art often portrays the dignity of work, and he was invited by President Carter to design a poster commemorating Labor Day 1980.

* Maria Enriquez de Allen, 75, a Mexican folk artist now living in Chicago who combines embroidery, quilting, crochet and clay modeling to form unique collages and decorated objects.

"As artists," says Zetlin, "we are engaged in getting to the kernel of experience. And as older artists, we have a broader experience to draw upon."

Zetlin, who enrolled in her first drawing class in 1956 after being "nagged to death" by a friend, does abstract work "because it goes beyond just seeing something to capture the experience itself."

Her work, she says, "has gone through many stages. For two years I did nothing but pears. I threw a bunch of them up in the air like birds and did a piece called 'A Skyful of Pears.' "

In recent years, Zetlin has worked with computer chips, Voyager photographs and transparency machines. Her new ideas, she says, "spin off whatever I'm working on. It's like a love affair--one thing leads to another with no mother to tell you 'Uh-uh.' "

She stumbled into her "microfiche stage" several years ago when trying to adjust the machine in the university library. "I noticed that when it was out of focus it made beautiful shapes," recalls Zetlin, who got a grant from Xerox in 1980 to use their machinery for her art. "I played with it, and subjected the black and white prints to a heat process to add colors. The librarians shudder when they see me coming."

Much of her inspiration comes from ancient designs and symbols. "Certain images, like snakes and fire, are common to all cultures going back to prehistoric times," Zetlin says. "Often they deal with magic and religion. They touch us in a central way.

"As far as feelings are concerned, we're probably similar to the way we were in ancient days. But as far as technology we're light years different." Producing these ancient, universal symbols with modern machines, she says, "is my attempt to capture the human experience of time."

She prefers machines to paint brushes, "because artists throughout history have always used the tools of their time, and today machines are our tools."

"A lot of people--young and old--are afraid of technology. But I love it. It has its fearsome aspects, but it's also a fascinating tool. I don't believe in longing after a golden past. I'm much too excited about living in the present."

Patina is open to the public weekdays from 10 a.m. to 4 p.m. at the National Council on the Aging, 600 Maryland Ave. SW.