AS THE 36th annual Tony Awards go on the air tonight (CBS, 9 p.m.), with the attendant splash and promise of increased ticket sales to the winners, a touch of perspective is in order:

As always theatrically, one should go back to the Greeks. The original of one of tonight's nominees, "Medea," was a nominee in the Athenians' contest of 431 B.C. It won third place. Nonwinners can take comfort.

Tonight's ceremony is a frankly commercial event; a Tony win, even a nomination, can extend a run and propel touring. For all the sport that can be made of Tony absurdities, theaters without audiences are of little worth. And often there is distinction in the winners.

Two of the candidates, Zoe Caldwell (nominated for best actress as Medea) and Christopher Plummer (nominated for best actor as Iago) give imaginative life to challenging, lasting roles. Their uncommon professional skills would distinguish them in any company of any period.

Outstanding, too, is the Royal Shakespeare Company's "Nicholas Nickleby"--virtually two productions in one--triumphant in adaptation, performance and technical details. When it became apparent in midseason that the show would romp away with honors long after its departure, the sponsoring League of New York Theaters' eligibility committee, to its credit, decided not to change the rules while the game was on. "Nick Nick" is eligible for eight awards tonight--best play, best director, best actor among them. And, if home-grown creations are unrewarded, that merely shows that the Brits have outstripped us.

The potentially closest race might be in the "best musical" category, but the recent "Nine" appears to have far more merit than the winter's leader, "Dreamgirls," with its nothing score and jerky book (although Michael Bennett's staging is brilliant). "Nine" operates on a far higher level: Maury Yeston's score demonstrates the style of a witty, knowledgeable musician and librettist Arthur Kopit, adapting Federico Fellini's "8 1/2," has charted a seamless journey through a frenzied man's head. Director Tommy Tune's star, Raul Julia (up for best actor in a musical), and three of his actresses--Karen Akers, Liliane Montevecchi and Anita Morris, vying against each other for best featured (or supporting) actress in a musical--are fabulously right, as are the sets of Lawrence Miller, William Ivey Long's costumes, Marcia Madeira's lighting and practically everything else.

Other promising nominees are Athol Fugard's "'Master Harold' . . . and the Boys," Beth Henley's "Crimes of the Heart," Ronald Harwood's "The Dresser" and Bill C. Davis' "Mass Appeal." All are about recognizable people and have theatrical zest and rewarding roles. You can't call a season with such works a total disaster.

But you do have to ponder. "Nick Nick" was British, Caldwell is Australian, Plummer Canadian, Fugard South African. Harwood, who actually was dresser to his pseudonymous hero, Sir Donald Wolfit, also is British. In this American awards ceremony, the highest Broadway confers, the Americans aren't doing too well.

The Tony is a creation of women, efficiently promoted by men. Its story dates back to World War I, when playwright Rachel Crothers and six other theater women formed "Stage Women's War Relief." In 1939, Crothers reactivated the group as the American Theater Wing, which seven years later created its own professional training school for service veterans. Among its graduates: Charlton Heston, Tony Randall, Pat Hingle, Russell Nype and James Whitmore.

One of the organization's top officers was an actress who had become a director, Antoinette Perry. After her death in 1946, colleagues decided to honor her memory by presenting awards bearing her name to contributors of distinguished work. The first, in 1947, were scrolls, and went to Jose Ferrer for "Cyrano de Bergerac," Fredric March for "Years Ago," Helen Hayes for "Happy Birthday" and Ingrid Bergman for "Joan of Lorraine." Two years later the now-familiar silver medallion was recognized as the official "Tony."

Women have continued to head the Theater Wing, with Isabelle Stevenson succeeding Helen Mencken in 1966. The next year the League of New York Theaters and Producers joined the Wing to present the awards, and a bit later producer Alexander H. Cohen began the telecasts, which have won recognition as the cream of award ceremonies.

Through the years categories have expanded, such as the one for regional theaters nominated by the American Theater Critics Association. Arena Stage was the first winner in that category; the Tyrone Guthrie in Minneapolis is this year's.

The process: a nominating committee of 13 theater professionals chooses four nominees for each category. These are voted on by directors of the Wing, the League, Actors' Equity, the Dramatists' Guild, the Society of Directors and Choreographers, the United Scenic Artists, members of the League and those on its first and second night lists--some 600 voters.

There are inevitable absurdities. Amanda Plummer, who has the title--and central--role of "Agnes of God," is nominated in the featured category because her name is listed under the title in the billing. Geraldine Page, whose role is smaller, is nominated for best actress; her name is above the title. Plummer, however, is nominated as best actress for her starring role in "A Taste of Honey."

Plummer's nominations plus her father, Christopher's, mark the first father-daughter Tony lineup. (Mother Tammy Grimes won her Tony in '61 as the featured, but title, player in "The Unsinkable Molly Brown").

Two other title role players received only feature billing: David Alan Grier, "The First's" Jackie Robinson, and Bill Hutton of "Joseph and the Amazing Technicolor Dreamcoat." And in "Master Harold," the most critical of its three roles is played by Zakes Mokae, but he, too, is nominated in the featured category. Though the Royal Shakespeare Company was billed alphabetically, Roger Rees, its Nicholas, has been nominated in the star slot.

The weirdest of the nominations came about because the season's musicals were such glub. The League insists on four nominations in each category, with the result that a dreadful little thing called "Pump Boys and Dinettes" has been advertising itself as "nominated for best musical."

Every effort is made to dress up the audience with all the nominees. Not all can show. Are its 250-odd members likely to represent the Royal Shakespeare Company? Not bloody likely. Katharine Hepburn is nominated for "The West Side Waltz," but this afternoon she'll be in Chicago, ending her tour with an Actors' Fund benefit.

New York theater's other major honors--the 27th annual Obies, for off-Broadway productions, were held in 44th Street's Savoy Theater. Obie was damned for Going Uptown, the heart of Tonyland, and for apparently following Tony's scorned commercialism.

Less categorized than the Tony, this year's Obies went to Tadeusz-Kantor's "Wielopole, Wielopole" (in Polish) as "best theater piece"; "Metamorphosis in Miniature" and "Mr. Dead and Mrs. Free," tied for best American play; and Maria Fornes, who won a "sustained achievement" award. Cheryl Churchill's "Cloud Nine," directed by Tommy Tune, copped three Obies, making this a Tune-full year.

With Tony covering one extreme and Obie the other, some works still fall between the cracks. This year a casualty was Charles Fuller's "A Soldier's Play," presented by the Negro Ensemble Company. Here the Clarence Derwent Awards came to the rescue.

English-born Derwent, who ran away from his family's diamond business to risk a life in theater, created these awards for the category he often found himself in, the non-featured player of New York or London. Though he never rose to star rank, Derwent had several terms as head of American Actor's Equity and created his $1,000 honor for the relatively obscure. Larry Riley, who appeared here in the touring "Pippin," received the male award for "A Soldier's Story." The women's spot went to Joanne Camp, who had several Arena Stage seasons before her presently honored Off-Broadway role in "Geniuses."