CALLING IT 'Platinum' wasn't our idea," said Will Holt (book and lyrics), leaning back in his chair at the Act III restaurant and gazing thoughtfully into the sauce on his lunch ("Is that Bearnaise? It looks Russian to me.")

"Paramount asked us to change it to 'Platinum' after they came in with a major investment," added Gary William Friedman (music). "We were calling it 'Sunset' when we brought it to Buffalo - the idea of a fading movie actress and a fading rock singer going off into the sunset, but Paramount thought people would confuse it with 'Sunset Strip.' When we thought about it for a while, we thought 'Platinum' was a pretty good name.

"At first, I wondered whether people who are not in the business would catch the meaning of platinum, but then I thought of my 10-year-old son, Courtney; he listens to the radio all the time and the disc jockeys are always chattering at him about gold and platinum. He didn't have any trouble at all."

For those who lack Courtney Holt's expertise, "Platinum" is the industry jargon applied to a record that has sold a million copies. It is also the post-Buffalo title of the new musical that has just opened at the Kennedy Center Opera House and will go on to New York's Mark Hellinger Theatre (where "My Fair Lady" got its start) on Nov. 12. Holt and Friedman, who have already worked together successfully on "The Me Nobody Knows," have been shaping the show through a variety of changes for the last three years."

Holt and Friedman naturally hope that their original cast album will fulfil the promise of its title, but at the moment they aren't even sure who will record and distribute it.

"One thing is sure," said producer Fritz Holt (no relation to Will), who has been lining up the $1.25 million required to take the show from Buffalo, through Philadelphia and Washington to Broadway, "it won't be recorded by Paramount. They don't make records; there's a company called ABC-Paramount, but it has no connection with the film company. We will have about six record companies coming down to take a look at the show during its first two weeks in Washington, including some companies that don't usually do original-cast albums, like Atlantic and Arista."

Paramount has invested $325,000 in cash and a large but imponderable amount in facilities, equipment and services to get first refusal on the show's film rights.

"What Paramount is hoping for is a picture that will cater to the 'Saturday Night Fever' crowd," according to Fritz Holt, "but the music has a very broad spectrum, from traditional Broadway style to '60s rock and '70s disco. We have a sort of composite of American pop music since World War II. The range is from wartime nostalgia to the contemporary sound."

This range is shown most clearly in a number called "Destiny," which is shown first in a film-clip from a movie called "Wings of Destiny" supposedly made during World War II by Lila Halliday (Alexis Smith). The song is arranged in the lush, dreamy style of sound-tracks of that period. Then, a few minutes later, it comes back in a crisp, disco arrangement, having been appropriated and changed by Crystal Mason (Lisa Mordente).

"The disco sound grew up while we were working on 'Platinum,' and the musical style of the show has changed a lot in the three years we have been working on it," Friedman said. "In the beginning, there was a strong folk element, which is nearly gone now. The disco sound works in well, because a basic theme is the changes in popular musical style. This is a change that Broadway has not wholly come to terms with. If you look in Variety, you will find that musical shows are still the mainstay of Broadway, but pit orchestras just aren't producing the new sound that people want on records. Hollywood has done much better, probably in part because the sound-track is an electronic medium."

"Platinum" (or rather "Sunset") began as a much smaller idea, involving a cast of four and designed to play to small audiences in the Manhattan Theatre Club. "I had been working with some veteran performers - the Andrews Sisters in 'Over Here,' for example - and I wanted to do something about the different styles of popular music we have seen since the '40s," Will Holt recalled. "That was the beginning, and Gary and I worked on the polarity of a movie star of the '40s and a fading rocker of the '60s who is beginning to wonder where he goes from here. Besides the musical contrast, there's a theme here in the evan escence of power; the rock stars have taken it away from the movie stars - they're living in a lot of those Beverly Hills mansions now - and the rock stars are beginning to notice what a short time stardom lasts."

The basic logistic problem was to get these two symbolic characters together in a situation with some romance and tension, and they did it by making rock star Dan Danger (Richard Cox) a fan of old movies who happens to be in a California recording studio at the same time as Lila Halliday, who is trying for a comeback as a recording artist.

From this simple beginning, the show has escalated to its million-plus status with the assistance of a variety of people, first of all comedian Jimmy Coco. "He brought it to me and my partners while it was still a small cabaret piece: Will and Gary played the music and sang the score at the Manhattan Theatre Club in the fall of '76," Fritz Holt recalls.

"By the time we get into New York, it will be a little over two years we have been involved - a bit longer than it usually takes to get a show to Broadway. After it tried out in Buffalo a year ago, the show went back to the drawing board with a fair amount of help from other people. Bruce Vilanch working with Will on the book; Joe Layton as director and choreographer, and others. Paramount Sound has put about $180,000 worth of sound equipment into it, and Paramount has let us use one of their sound stages to rehearse; they have given us parts of the set and let us make use of their costume shop. Most important of all, they have thrown open their promotion department to us.

"What Paramount sees from this is a relatively inexpensive way to develop a piece of material that they can use later - they usually spend so much money to develop screen plays. In a way, the Broadway run will be a kind of market test for the material, too."