THE MANY MASKS OF MODERN ART; The unsung revolutionaries

It still surprises some that women can be successful revolutionaries, and that they can be at least as dedicated to ideas and ideals as men. No amount of hard evidence to the contrary has yet fully disabused everybody of the notion that men are the ones who do the serious and important thinking and doing, and that women are best fulfilled if they busy themselves with other things.

It's a comforting notion, I suppose, to quite a few men, but it's an archaic one nevertheless. Too much has happened during the past century, and most particularly during the past two decades, for such a notion even to be open to debate.

Nowhere is this more true than in the arts, where women now stand very much in the forefront. They still may not receive equitable treatment, but the quality of their contribution and the depth and range of their influence are beyond dispute.

This is particularly true in the visual arts. The days when men outnumbered women almost 20 to 1 in the galleries are gone. Men may still be better off professionally in many ways, but women are rapidly catching up.

When it comes to quality, however, especially among younger artists, women more than hold their own - or actually surpass the men. My personal list of exceptionally promising or talented artists under 35 contains a few more female than male names, and among even younger artists the ratio favoring women is even more dramatic.

It is also increasingly difficult to differentiate work done by men from that done by women. Subtlety and delicacy are no longer assumed to be largely feminine traits, and power and assertiveness are no longer held to be primarily masculine. Artists of both sexes increasingly feel free to be themselves in whatever form or manner is most appropriate.

This is not the first time, however, that this has been so. Men and women worked in close alliance and in very similar styles at the time Russian avant-garde art came into prominence during the first two decades of this century. In point of fact, some of the most dynamic and innovative artists of that period were women. For sheer revolutionary fervor and idealism, very few artists of the 20th century can match Alexandra Exter, Vera Pestel, Liubov Popova, Olga Rozanova, or Nadezhda Udaltsova. Individually and collectively, they produced some of the most astonishingly original art this century has seen.

It's their unfortunate fate, however, to be largely unrecognized today. But then, only a handful of the hundreds of good to exceptional artists, male and female, who constituted the Russian avant-garde of the pre-Stalin era are known to any but a few specialists.

Liubov Popova, in particular, deserves much wider recognition. Everything she did, from her early, modified Impressionist works to the starkly Constructivist canvases of the 1917-21 period, show her to have been a restlessly probing and highly innovative modernist of outstanding talent. But she was more than a theorist, for she also applied her talent toward practical ends, designing posters, textiles, costumes, and stage sets when she was asked.

Popova was, without doubt, one of the most exceptional artists of the early 20th century, and definitely deserves a higher position in our art-history books than she now enjoys. Her problem as far as the public is concerned is that she was a formal purist working toward a thoroughly nonobjective style. She was more interested in the dynamics of new ideas than in the production of highly polished paintings, and so her works seem a bit too formal and theoretical to most laymen.

One artist of that time and place who did achieve considerable recognition, however, was Natalia Gontcharova. This was due partly to the fact that she continued her career in Europe after Stalin's suppression of all avant-garde activities, and partly to her affiliation with other famous movements, artists, and institutions - most particularly Diaghilev and his Ballets Russes.

All that, of course, would have meant very little if her talent hadn't been impressive - and it was. Although born into an ancient noble family, she quickly found her artistic identity as a member of the Russian avant-garde. She participated in many of the most advanced exhibitions of the period in Russia and Paris while still in her early 20s, helped Mikhail Larionov (her mentor and ultimately her husband) in the organization of several others, and showed with ''Der Blaue Reiter'' in Munich in 1912.

She also illustrated books by the Futurists, made a film with Larionov in 1913, and did everything she could to further the cause of the avant-garde.

Among her best-known works are those executed in accordance with, and as an extension of, Larionov's Rayonist theory. This theory, although partially derived from Futurism, was essentially Larionov's own method of evoking feelings of the fourth dimension on a flat surface. It held that a painting should not depict the object itself but derive from the patterns established by the dynamic interaction of the straight rays of light the object reflected. (Reality, in short, was to be abstracted into lines of force.) The resulting images consisted largely of dense clusters of straight, intersecting lines, tended to be bright and colorful, and more often than not, were very effective.

This was particularly true when Gontcharova personalized this theory with her own very special painterly touch, and produced works whose warmth and celebration of life took them well beyond theory and into the dimensions of true art. These canvases, which constitute her chief claim to fame, now hang in many of the great museums and private collections throughout the world.