Ancient and modern self-portraits: sometimes vain, sometimes candid

The art of the self-portrait has a long and noble tradition. Some of the world's greatest works of art are self-portraits - witness those by Leonardo, Rembrandt, Durer, Goya, and Cezanne.

And there are many others, painted or carved by anonymous artisans as part of vast architectural projects, that tell us almost all we know about those long-gone and otherwise forgotten individuals.

A self-portrait can be an occasion for vanity or for ruthless self-appraisal. It may have been created to remind a long-absent friend of the artist's appearance - or because painting a self-portrait was a cheaper way of learning how to paint than hiring a model.

Some painters produced self-portraits annually to record their impressions of time's effects, while others painted themselves only once - or not at all. Some portrayed themselves dressed up as kings and emperors, others chose to be seen as clowns and mountebanks. And there were always those who painted themselves peering knowingly from the ranks of heroes and royalty.

The 20th century has produced many fine self-portraits, from the starkly realistic to the stylized and largely ''abstract.'' Some, such as those by Kokoschka, Kollwitz, and Beckmann, have been hauntingly direct and human. Others , by Chagall, Matisse, Klee, Miro, etc., have tended to represent the artist's modernist style more than his physical appearance. But whatever the approach, painting his own likeness has remained an important act in almost every artist's life.

Vivid proof of this can be found in the Allan Frumkin Gallery's two-part exhibition here of contemporary self-portraits. Straightfor-wardly ''serious'' works are played off against self-portraits in which the artists strike humorous , sardonic, or derisive poses. Neither wins out, but together they add up to an intriguing exhibition.

A goodly number of the straight pieces are frontal, probingly direct, and humorless - as though their artists were determined not to see themselves through rose-colored glasses. Alice Neel, in particular, insists we see her precisely as she sees herself in the cold light of day - with the result that her self-portrait is as frank and as heartbreakingly revealing as any painted in recent years. William Beckman, James Valerio, and Alfred Leslie also seem to prefer stark objectivity to more sentimental attitudes. And Philip Pearlstein comes across as cool and detached as ever.

In some ways, Joan Brown steals the show, both with her straight self-portrait and the more lighthearted one in which she depicts herself as half human and half feline. Deborah Deichler, an artist whose work I hadn't encountered before, makes her mark with ''Lot's Wife,'' Robert Arneson comes across with one of his better ceramic self-portraits, and Paul Wiesenfeld scores beautifully with his half-length study of himself.

I was also taken by Red Grooms's ''Diagonal Self-Portrait,'' and Peter Saul's ''Donald Duck Self-Portrait'' - although the latter comes terribly close to being a cartoon. In all, it's an excellent show that includes outstanding examples of ''serious'' contemporary self-portraits, as well as a few works of quality that reveal the less solemn and more derisively fun-filled aspects of certain artists' perceptions of themselves. I only wish it could have been larger and more inclusive, but that would have required the sort of space only given to museums these days.

'Self Portraits,' at the Allan Frumkin Gallery, 50 West 57th Street, through Jan. 27. New international stars

For those not yet familiar with the work of some of the newer international ''stars'' in painting, I suggest a visit to the Rosa Esman Gallery here. It need not be a long visit, for the number of works on view is small, and the quality of most of them is not particularly high.

Three Italians, Sandro Chia, Enzo Cucchi, and Francesco Clemente, comprise the bulk of this exhibition of some of today's younger and more wildly impetuous painterly heroes. A few additional pieces by the German, Anselm Kiefer, and the American, Jean Michel Basquiat, round out the show.

Of the group, Chia comes off best, not because he is represented at his highest level of quality (which isn't particularly high at that), but because what he is represented by quite adequately conveys what he is trying to do. Basquiat, on the other hand, comes off very poorly, thanks to work that shows us little of what he can do with paint. This is unfortunate, because this young man , barely into his 20s, has a passionately genuine if still somewhat unfocused talent.

Other than that, it's difficult to know what to say about this exhibition. It's worth seeing in order to keep up with what's going on, but certainly not if one is searching for a significant aesthetic experience. In a way, viewing it is like reading the daily papers: It helps keep us aware of what is happening, and provides some food for thought.

At the Rosa Esman gallery, 29 West 57th Street, through Jan. 15.