A Blast Of Pure Colour

The English artist Patrick Heron has been, famously, a vocal champion of British painting, contending that in the 1950s the American Abstract Expressionists took their lead from the artists' colony of St Ives, rather than vice versa. So, it may seem churlish to say that there's something almost un-English about the major retrospective exhibition of his painting currently showing at London's Tate Gallery.

What's surprising is that it provides such a blast of pure colour, from the dripping, kaleidoscopic garden studies of the 1950s via brilliant stripes to the blistering reds, yellows and purples of his 1960s and '70s abstracts. It's not that we're unused to seeing this kind of palette so blatantly deployed, but it's generally in paintings originating on the far side of the Atlantic. No cultural stereotyping intended, but the English audience seems to have trouble with this kind of thing. They know the angst of Bacon and Freud equals high seriousness, but bright colours make them uneasy.

Heron's thesis isn't as unlikely as it may sound on first hearing, but the fact is that he is himself unusual among British artists. To wander through the exhibition is to accompany him on a highly personal journey, to sense his continual excitement in discovery and his unparalleled engagement with the process of making paintings. And there is also the feeling that he is a comparatively isolated figure.

In fact whether considered as painter, thinker or writer, he is a formidable individualist who is admirably indifferent to conventional wisdom.

Born in Leeds in 1920, he spent several happy years of his childhood in Cornwall before the family moved on to Welwyn Garden City in 1929. Matisse and, more conspicuously, Braque were the dominant influences on much of his early work, though Cezanne and Bonnard were also strong role models - all French.

He worked as an art critic for the New Statesman and other publications. From his late teens he revisited Cornwall regularly, gradually getting to know the artistic community there. Then, in 1955 he bought Eagles Nest, the house in Zennor where he had lived briefly with his family in 1927, and where he still lives now.

In the decade following his move to Cornwall he had a fantastic run of work. First came the garden paintings, loosely inspired by the spectacular blooms of the azaleas and camellias in the garden at Eagle's Nest. Next came the purely abstract stripe paintings - just vertical or horizontal bands of colour. They were remarkable for their time, anticipating developments in American painting, and they still look amazing. Then came more atmospheric compositions, using sequences of squares and disks against ground colour. They have affinities with the work of several other painters, including William Scott, but they stand entirely on their own in their use of colour. Then the softness gave way to simple, hard-edged compositions which relentlessly hit the high notes and can, admittedly, be wearing when seen en masse.

The crunch came in the latter half of the 1970s, though the problem had been pending for some time. Heron is a painter who doesn't stay still - in fact he was critical of American artists for merely repeating themselves - yet for over a decade he had employed a more-or-less static pictorial vocabulary. How to develop this self-sufficient style? In the event, other matters intervened. He became ill; Delia, his wife, died. For a while he did no work.

When he began to paint again, he had moved on. The impassive colour surfaces were broken up and the free, rambling line of his Braque phase was reintroduced as he moved towards greater and greater informality, often using the pure white ground of the canvas as a vital element of the composition. He turned again to the garden for inspiration. A visit to Australia was also important. This period has produced some outstanding paintings, and it achieves a stylistic synthesis between the various elements of previous work. But it is not always convincing.

Some of the really spare pieces, with just a few lines, a few clouds of colour, seem to aspire to the spontaneity of Japanese brush drawing, without its casual precision. The question raised by the latter half of the retrospective is whether he figured a way out of the impasse created by the very success of his hard-edged pictures. And, so far, the answer is only a qualified yes. But then, his achievement is considerable, and he still has a lot of painting to do.

Close by in the Tate, crowds throng to see a one-room show of work by Lucian Freud, called simply Some New Paintings. They congregate, particularly, before one tiny canvas, a nude portrait of Jerry Hall heavily pregnant. Freud isn't just a painter of flesh, though no-one paints flesh as strangely and strikingly as he does, and his paint surface is getting more clotted and knotty as he goes on, particularly around knees, ankles, elbows, hands and faces.

He is capable of capturing a vivid sense of solitary existence in his portraits. Sometimes the actual nakedness of his sitters is a distraction from the emotional nakedness that he seems to be after, but when he gets it right the results can be stunning. Here, a painting of a woman sprawled face down on a red sofa and a study of Leigh Bowery are among the best pieces. His bigger, more theatrical compositions are less effective. The most untypical picture is an hypnotically fascinating study of vegetation, Garden, Notting Hill Gate. Meticulously realistic, it functions like an abstract all-over composition that your eyes can explore endlessly.

Since his first one-person show in the Whitechapel Gallery in 1991, Peter Doig's career has come on in leaps and bounds. He won the John Moores prize in 1993, was on the Turner Prize shortlist the following year, and has had many shows in Europe and the US: good going for a representational painter, when it's a distinctly unfashionable thing to be. But Doig is that unusual phenomenon, an artist popular with both audiences and (most) critics.

Unusually, his phantasmagoric paintings cheerfully advertise their origins in casual photography, popular cinema, even advertisements. His Canoe-Lake, for example, in which a woman in a canoe trails her hand in the water against the background of a distant wooded shoreline, is typically ominous - hardly surprising, given that the original source is a still from the film Friday the 13th. Even when there isn't such a specific reference, films keeps coming to mind in relation to the paintings.

But Doig doesn't just raid the archives of popular culture. Much of his imagery derives from rural Canada, where he grew up. His parents moved there in 1960, just a year after he was born in Edinburgh. Since 1979 he's been mostly based in London. Not only are his paintings very big, they also evoke the sheer size of the Canadian landscape.

Nor does he simply reproduce his source photographs, like a photorealist painter. He feels free to distort and embellish an image every which way, blurring, fragmenting, distorting the colours. He has a particular penchant for sprinkling blobs and blotches of paint arbitrarily across the surface, as if drops of chemical solution have blemished a photographic print. He loves acid colour combinations and often incorporates incongruous little passages of paintwork that shouldn't fit in with anything else. Yet his pictures work very well as overall, coherent images.

During a residency at the Irish Museum of Modern Art, Hughie O'Donoghue began to archive his late father's papers. They included over 300 letters written home while his father served abroad during the second World War. It turned out to be an enormous project that has continued since he moved to his new home in County Kilkenny. A Line of Retreat was his first exhibition directly addressing these concerns. Now a show of new work, Crossing the Rapido, again at Purdy Hicks, is concerned with his father's experience of the Italian campaign.

O'Donoghue is an exceptional textural painter and printmaker, capable of investing a surface with a sombre intensity of feeling. With little explicit figurative imagery - a sculptural figure of Marsyas from a contemporary picture postcard and place-names scrawled on the canvases - he generates an apocalyptic sense of a continent in turmoil, and seamlessly links this epic sweep to a deeply personal, individual involvement. It is a powerful, moving exhibition.

American artist Frank Stella, whose show of new work has just finished at the Bernard Jacobson Gallery, has long shaken off the "father of minimalism" tag, as his paintings have developed into ever more frenetic and colourful sculptural reliefs. His recent work has an incredibly complicated genesis, partly involving the computer manipulated images of cigar smoke employed in hyperactive three-dimensional compositions. It should be terrible, but in the event you have to admire him.

I've never seen a surface quite like the one he's made. It's complicated and dazzling, a kind of technological baroque, and it does make you wonder how on earth he did it.

Patrick Heron continues at the Tate Gallery, London until September 6th. Admission £5.

Lucian Freud: Some New Paintings continues at the Tate Gallery until July 26th.

Peter Doig continues at the Whitechapel Gallery until August 16th.

Hughie O'Donoghue: Crossing the Rapido continues at Purdy Hicks until July 11th.