HE IS AN "artist," says Bob Furnard, senior producer at "Good Morning America." "He made Barbara Walters look 10 years younger."

He has "the fastest makeup fingers in the East," maintains ABC correspondent Bettina Gregory.

He appears to be the Elizabeth Arden of network news. A make-over man. Not to be confused with a makeup man, which is standard at each network, the person who slaps pancake makeup on correspondents and celebrities minutes before the news.

But at ABC, there seems to be some difference of opinion about just what John Mastrianni does. He says he makes over the on-air people. Officially, ABC says he just makes them up.

"John is not paid to make over people," says Kitty Bayh, ABC's director of news information in Washington. "He is paid to make people camera-ready. If John changes an overall look, it is because they are sitting in his chair and he is offering his advice. He clearly doesn't have a mandate to do that."

Mastrianni, 32, says he often starts days, weeks, months before air time to get his people ready to deliver that two-minute spot on unemployment figures or news about the latest White House crisis. A little more blush here, a different haircolor there. He toils away from 4 in the morning until 7 at night in his mirrored alcove supplied with eye shadow, cotton balls, contact-lens solution and file face charts on all the news stars. He doesn't just slap on pancake. He goes for the image.

"Very much like theater," he says. "A lot of ego stroking before the performance."

His pink room is a few steps away from an impressive glassed-in studio with rows of twinkling closed-circuit televisions. ABC may be No. 2 in the ratings, but Mastrianni says the network is ahead in makeup. "They know what it takes to make people look good."

"Our way of presenting the news has changed," says Jaye Malkie, ABC's deputy Washington bureau chief. "I think that has placed an emphasis on the way people look."

Roone Arledge, flamboyant president of ABC News, disagrees.

"We don't do enough," says Arledge. "We spend less time than the other networks. We wasted three years not doing justice to Barbara Walters. If we tried to do what they CBS did -- if we told Frank Reynolds to wear a sweater vest, he'd walk right off the set."

Says Lillian Brown, CBS's makeup chief, "We certainly do not make them over. We make them feel better. But Lesley Stahl and Diane Sawyer are beautiful women. They don't need much."

And, from Sadie Zuzzolo, head of makeup for NBC, New York: "These are news people, not performers. We are not getting them ready for a role but for the news. We don't make anybody over. This is not show business."

"The idea," says Arledge, "is to reconstruct reality. Mastrianni's not there to enhance a person's looks, but to make them look like they normally look."

Mastrianni describes his work this way: "I make them over to fit their personality," he explains over chef's salad at Joe and Mo's. "I redo people over a period of time . . . Sometimes it takes a long time to shift someone's image of themselves."

Case studies:

* Twelve-year television veteran Carol Simpson and the false eyelashes problem. A "redo" and a Mastrianni succees.

"He called my false eyelashes 'Bambis,' says Simpson, quite pleased with her new look. "He said, 'Dear, we have to get rid of those Bambis.' It is more show biz in that he makes us feel better, and if we have confidence in our appearance, it enhances the product . . . It's wonderful."

* Sheilah Kast, former print journalist. A recent redo. Makeup. Shorter hair. Somewhat of a success.

"I would say it was 50 percent make-over," says Kast. "Partly, I feel better in terms of camera work because I know it looks better . . . But sometimes I think it looks a little more sophisticated than I look inside. I look a tad haughty."

* Steve Aug, seasoned print journalist, recently turned television correspondent. A reluctant success.

"Now there's a guy that can even make me look good," says Aug, who first had the make-over news broken to him last year when he joined ABC after The Washington Star folded. "They said, 'You're good,' but they kept mumbling some about 'cosmetic changes.' "

Color around the cheeks. Shadowing under the eyes. A new, blown-dry cut to make thinning hair look fuller.

"Two years ago I would have thought they were nuts if anyone told me I'd be blow-drying my hair and wearing face makeup," says Aug. "My wife thinks I look 20 years younger . . ."

* Frank Reynolds. "He doesn't like to talk about makeup," says Mastrianni, who does the anchorman every day at 5. "It's one of his idiosyncrasies. No one can watch." Reynolds could be reached for comment.

Mastrianni has been on contract with ABC for five years. With his education -- psychology at Georgetown, theater at the Royal Academy of Dramatic Art in Toronto -- he is appropriately trained to hand-hold, mediate, counsel, ego massage and redo.

He starts his day when he does Kathleen Sullivan and Steve Bell for "Good Morning America." It is the beginning of a very long day. He leaves ABC at 10 a.m. to work at other jobs, such as simulating wounds on models for medical books. Gunshots. Knife wounds. Car accidents.

At 3 p.m., he's back at the vast bureau building on DeSales Street, sharpening his eye liner and lining up the blush for Reynolds and the parade of correspondents who will appear on "World News Tonight."

"You're getting them at the worst possible moment. You try to relieve their pressure and tensions. I have to have their consistent trust, and they have to know I care that they look their best. Very sensitive area. One disastrous result and they won't come back."

"It's a strange situation, you know," he explains. "You're balancing the ego while helping people shift perceptions of self. I'd say that 99 percent of it is dime-store psychology."