Master Minimalist

The superb Ellsworth Kelly show at the Tate Gallery has just ended, but the exhibition Mondrian: Nature To Abstraction runs there until November 30th. It is tied to no obvious date or anniversary, since Mondrian died in exile in New York in 1944, aged 72. Its chief interest is that, as the title states, it takes you from the cradling of Mondrian's art to its bare, virtually Minimalist final stage.

Mondrian's early works are seen more often in reproduction than in the reality, and they are decidedly flattered by the former. Frankly, if some sound and honest Dutch critic of 80 years ago had been invited to see them and give a verdict, he could hardly have predicted a golden future for their creator; he might even have advised the young Mondrian to give up art as a vocation. These vaguely Symbolist, fin-de-siecle pictures - sometimes of typical Dutch scenery with windmills and rivers, sometimes with attenuated human figures - are often sickly in colour and sentiment, as well as being dully and joylessly painted. The later master is as yet nowhere in sight.

Even then Mondrian enjoyed painting trees, a motif which led him into his now-famous Cubist phase in which he broke up his subject into quasi-geometric areas and stressed the flatness of the picture plane. What is more, a genuine colour sense began to emerge. From there, compelled by an almost fanatical urge towards simplification, he moved into the kind of complete abstraction we know so well, with squares and rectangles defined by barred black lines, and with colour often restricted to the primaries.

Mondrian's historical importance is immense, and I don't doubt for a moment that from his (rather late) maturity to the very end, he was a genuinely great and unique artist. Yet he works most of the time along a single track (which far too many have followed after him), he does not offer much formal invention or variety, and his innate puritanism did not allow him to take much joy in the handling of paint. Perhaps, too, this exhibition is unadventurous or limited in its choice and does not show certain late works like the Broadway Boogie Woogie, in which Mondrian appears to have gone on a new tack.

The Belgian Expressionist James Ensor (1860-1949) is not everybody's artist, even to those who genuinely respond to Continental Expressionism in general. He was an isolated figure, probably more than a little mad, with a vein of visionary paranoia which centred on images of faces with coloured masks. So much a glimpse at any art history can tell you; the question is, how good was he?

After seeing the exhibition at the Barbican, I find it hard to answer that outright. There are key works missing - notably the big Entry Of Christ Into Brussels which by general consent is his masterpiece, and undoubtedly Ensor's vison petered out and his style became commonplace. This is always the danger with isolated, almost freak artists who have no ancestry or tradition to support them; they live on their nerves, and their nerves are necessarily fallible. Ensor is a classic case of this, yet what cannot be denied is the hallucinatory power of his colour, and his strange and grotesque humour. Also on view in the Barbican is an important retrospective of the photographer Don McCullin, covering his career from 1959 to 1997. Both until December 14th.

Out in the Whitechapel Gallery you may see the paintings of David Alfaro Siqueiros, one of the great Mexican mural generation of the 1930s and an active Leftist in his own right - he was once implicated in a plot to kidnap Trotsky, and may also have been involved in his assassination (until November 2nd). At Bernard Jacobson there are recent works on display by Robert Rauschenberg, one of the original prophets of Pop Art, which I found notably weak and disappointing (until November 1st). Sculptures by the late, excellent Robert Adams, who had some Irish connections, are on view at Gimpel Fils until October 25th.