Clairol only had it part right. It's Frank Farmer who knows for sure.

He is a hairdresser, no question. But Farmer's specialty involves psychology, not dye. He produces cuties, but for family albums, not Ladies Home Journal. He is, as he painstakingly phrases it, "a haircutter, a professional children's haircutter."

And he is not just another pretty pair of scissors. Frank Farmer has been cutting children's hair in a town that values its grooming since 1931. He has done it so well that people call him an institution to his face.

Farmer has trimmed Kennedys. He delocked the Johnson daughters. He has "done" the children of diplomats whose names he didn't even know how to pronounce.

But Farmer has done the children of GS-5s, too. And he feels the same about the would-bes: "I've taught a lot of mothers a few things about children."

The Farmer Method is to be firm yet friendly. The main idea is never to make an already nervous situation worse. So when a balky kid approaches Farmer's cubbyhole in the beauty salon of the Chevy Chase Woodward & Lothrop, Farmer immediately, lets the child call the shots.

"Sometimes they've been crying all the way from parking lot," says Farmer, never pausing as he puts the finishing touches on Alex Sierck, 7. "So you don't drag them in here. You never drag a child anywhere. If they want to, well, it's usually all right.

"You got any children got to be tamed?" he asks, dispatching Alex with a pat to the shoulder and a lollipop into the right paw. "Send'em down to see me."

So many Washington parents have done so for so long that Farmer is almost as famous for his longevity as he is for the quality of his work.

Ann Miller, 24, now cosmetics manager in the Woody's beauty salon, remembers coming for her first Farmerization at the age of 2. Marlene Berman, a cosmetician, remembers bringing her daughter, now 20, for the daughter's first haircut. And Alex's mother Susan says she knows plenty of fellow mothers who bring their kids to the same shearer who sheared the mothers a generation ago.

Through it all, Frank Farmer has stood as he stands today - slightly beside current "victim," a half-smile on his face, a sign behind him on the mirror that reads "Mr. Farmer," thus suggesting a little class.

Farmer never uses gimmicks (no piped-in rock music, no wine, no razor cutting), and never use water of pornade. His only concession to "modern cutting" is a blow dryer, "and I was using one 40 years ago. What's the big deal?"

Farmer usually works on an appointments-only basis, at the unisex rate of $6.50. But he will squeeze in an emergency when the situation obviously demands it.

Obvious was not the word for Kellie Amtower's situation two and half years ago. Crying shame was more like it. A storybook blonde, Kellie, then 4 1/2, decided to coif her own self one day at home, using the family scissors. She had nearly Yul Brynnered one whole side of her head before her mother, Cecilia, discovered her.

"Mr. Farmer took her right away," Mrs. Amtower recalled, as an older wiser and fully regrown Kellie clambered into Farmer's chair. "There wasn't a lot to work with, but he did a marvelous job."

Farmer is no stranger to prospective Kojaks, since he is close to being one himself. "Been this way, since I was 25," he said. "I guess it runs in the family."

There wasn't much family for it to run in when Farmer was young. An orphan, he migrated to Washington from his native Scranton, Pa., as a young man to look for work.

He did not exactly surge into haircutting. He knew nothing about it, and knew that he would have to learn. "So a fellow I knew at 10th and H let me use his (barber) shop at night. I'd shave the bums, give them free haircuts and shaves. I did it just to learn."

In 1931, with the help of store executives he had met, Farmer opened a children's chair in the downtown Woody's. He opened his own all-ages downtown shop in 1939, but much of the hair in those years was cropped close, and under enemy fire. So in 1942, Farmer went back to children and uptown to the Garfinckel's in Spring Valley. In 1951, he rejoined Woody's at their then-new Chevy Chase branch.

Last year, Farmer cut his "office hours" from five days a week to three. "I thought it would be best to survive a little longer," said Farmer.

The result, though, was that the rest of the beauty salon almost didn't. "When he's away in August, and all during the week, it's horrible. People are like frantic," said Ann Miller.

That's the one thing Frank Farmer never is.

"I'm very mild-tempered. I can read human nature. The minute you step in the door, I know just how to handle you," says the man who has handled thousands - and claims to recognize most of them years later.

One of the toughest to handle, Farmer recalls, was the young Luci Baines Johnson.

"She was ready to go all the time," Farmer remembered - usually straight through the roof. One day, neither her mother nor her Farmer could get her to relax for a haircut, and a call was put through to the Senate Majority Leader's office. The familiar Texas voice lobbied Luci into submission, as it did so many others.

Try as he might, Farmer has been unable to make long teen-age hair submit.

"Some of these young girls, they almost cry if they think I'm cutting off too much hair," says Farmer, shaking his head. "And the boys are worse. They jump up and say, "Wait a minute! That's enough.""

But Farmer's pleasure is the pleasure of an artist, and for that reason, it transcends whatever demands hair fashion may make at any given time.

"I try to do my work so it would be difficult to duplicate it," Farmer says. "And I haven't done badly. I don't have any regrets."

Or as Marlene Berman, coworker, puts it: "There's nobody like Mr. Farmer."

Or as Alex Sierck, customer, puts it: "He's fine."