If perestroika seems slow to influence Soviet features, its effect on documentaries is clear in Black Square, an original and lively look at 20th century avant-garde painting in the USSR.

Directer Pasternak approaches his subject with a real feeling for the visual and for the joys of filmmaking. The Soviet avant-garde is traced from Russian Constructivism to a brief flowering in the Kruschev years, stagnation under Brezhnez, and the current revival of interest in this form of art.

The film is an unprecedented record of the works themselves. Here are Bulatov and Bruskin, Kabakov and Iankilevskii, Sidur, Neizvestnyi and many others.

What further impresses about Black Square, however, apart from its informative side, is how it links artistic production to the changing political climate. Revealing footage shows Nikita Kruschev skeptically viewing a modern "non-official" canvas. Another typical newsreel has the head of the Artists Union in the 1950s making fun of the same object while his audience laughs in agreement.

Numerous short interviews with contemporary painters point up the atmosphere of creative liberation that has followed on from perestroika. Watching fascinated Russians at a show of what used to constitute "non-official" art makes one wonder how many avant-garde works have left the country, never to be seen again.

Pasternak succeeds splendidly well in outlining cultural politics after the Revolution in this concise, engrossing study which sustains a true historical dimension as the title's allusion to Malevich implies.