Public TV -- America's soapbox for individual opinion

Almost every day there is evidence that Public Broadcasting is moving even further into the lead in providing a public outlet for privately held opinion. Two extraordinary documentaries by two extraordinary women make their television debuts this week with highly individualized presentations of their versions of reality.

These programs would find it difficult to secure a place on commercial TV. In fact it is hard to find documentaries like this anywhere in the vast semi-wasteland that is over-the-air TV today - but some creative listings-reading on the part of the viewer can often prove to be especially rewarding. (Anybody searching for such worthwhile TV these days will find it appropriate to turn first to PBS; then, if non-pay cable is accessible, to ARTS, with a look-in here and there at TeleFrance USA and Ovation. On pay services, the Entertainment Channel seems to be offering the most acceptably literate if not ''egghead'' programming.)

Both Women and the Economy on Talking It Out (first of six parts; airs on PBS , Tuesday, 10:30-11 p.m., check local listingsm) and Ellis Island (PBS, Wednesday , 9:30-10 p.m., check local listingsm) are part of the ongoing Public Broadcasting determination to provide a safe haven for independent documentary-makers. ''Frontline'' (Mondays on PBS), which is showing evidence of becoming PBS's highest-rated public affairs series ever, is the only regularly scheduled documentary series on national television, and it utilizes mainly independent documentarians whose work can seldom find a place on commercial TV.

''Women and the Economy'' is a straightforward, no-kidding-around status report on women in our society, written and directed by Mary Mangan, who was also executive producer. A few months ago, a group of 140 female opinionmakers was convened in Washington from all over the United States. Ms. Mangan was there to videotape the prime movers, then proceeded to wander about America, searching for the proper images to convert what could have been a simple talking-head documentary into a full-blown, important statement. Jean Stapleton adds a great sense of commitment and sincerity in her narration (and as a participant).

''We're not going to go away . . . and we're not going to go home again,'' is the stirring end to this comprehensive report on the women who now make up more than 50 percent of the American work force. According to writer-director Mangan this documentary is only the beginning.

In an interview, she told me that the other segments will concern women reentering the labor market, women in politics, university women, middle-class women, and those who are corporate executives.

''Using a conference at the core is fine, but stand-up talking heads alone would not work,'' she said. ''I hope this documentary will prove to be a cutting-edge approach to a different way to do a conference documentary.''

Has being a woman proved to be a special handicap to Ms. Mangan as a documentarian?

''No!'' she said emphatically. ''Women in documentary-making simply take their place as female entrepreneurs. We have the same problems, no more, no less. What we have to cope with first is the tendency of people to think we may be fine at the creative level but incapable at the business level. Now there are enough of us succeeding so that the old stereotypes are breaking down.''

Ms. Mangan has nice things to say about PBS, where several of her documentaries have already appeared. ''PBS has always offered good opportunities for independent producers. If you treat your own work seriously and your product is decent, they are always willing to take a look . . . and, perhaps, find a place for it on the schedule.

''Those of us who make our own documentaries are willing to scramble for money and then for exposure, as long as we can retain some sort of control of the imprint we make . . . so the magic is clearly ours.''

Meredith Monk

''Ellis Island'' is a lyrical film which can be called a documentary only because it chooses to illuminate a single subject - the island that processed more than 16 million immigrants between 1892 and 1927. The film, which has already won several Festival awards, is being presented on PBS under the auspices of the ?WGBH/Boston? New Television Workshop at WGBH, Boston, but it was originally funded by the National Endowment for the Arts, the Corporation for Public Broadcasting, and West German public TV.

Miss Monk, who has already made her mark in music, is comparatively new at documentary-making - this is her first lengthy film (half an hour). Conceived and directed by Miss Monk, who also did the music, it is filled with unforgettable images, flowing movement, evocative sounds, deja vum memories. Narrationless, it depends upon visuals and sounds to re-create the essence of Ellis Island, rather than the actuality of it. Determinedly avant-garde, it nevertheless is not cloyingly so. I am willing to guarantee that viewing ''Ellis Island'' will prove to be an unforgettable experience for just about everybody.

When I indicated to WGBH that I would like to talk to Miss Monk about the film, it was arranged that she would speak to me from Stuttgart, West Germany, where she was recording a new record.

''The film is not a documentary,'' she insisted by overseas phone. ''It is a poetic, atmospheric look at a place and a time. There is no narrative structure.

''Since my background is in music, dance, and theater, film is a logical direction for me. It utilizes the same sounds and images.

''Since the silent-film days, film people have not been working enough with images, the poetry of the image, the musicality of the image. . . .''

Miss Monk believes that film and music especially have a great deal in common. ''When I was editing the film, it was like writing music. You're dealing with the rhythm of imagery, just the way you do in music with the rhythm of sound. In film it is the essence and the rhythm of image and sound, working on counterpoint or whatever, that you are dealing with all the time. It is a very sensuous medium and that's why I love working in it.''

She is optimistic about the future of the avant-garde on TV. ''There is an audience for new work - it's just a matter of the people in charge taking a few risks.

''Certainly there is more of this risk-taking on PBS than anywhere else. The quality of such work on German television is very high.

''Wouldn't it be a terrible thing if there wasn't a public television system in America to do such things?''