Suited and muted

Callum Innes is a remarkable painter: his work is as much about what he takes away as what he chooses to leave on the canvas. He has been nominated or shortlisted for every big painting prize, and his controlled, almost monochrome, canvases were awarded the pounds 26,000 NatWest Art Prize last year.

Yet that success and style have stemmed from a drastic paring-down of the approach he was using after he left Edinburgh College of Art in 1985. "I was making something I wasn't happy with," he says. Breaking from figuration, the backbone of his art-school education, and the tradition of mythology used by Scottish East Coast painters, Innes stripped away the figure from his work, eventually concentrating on the ground, the painting's surface. "I emptied out the work - the figure became an oval, then a colour, then eventually it wasn't in the painting and the background became relevant." Concentrating on colour, with a nod to the abstract expressionists Mark Rothko and Barnett Newman, Innes carefully painted fields of colour on to canvas. Initially he tried to deny that his work was produced by hand at all - he wanted to get rid of the brushmarks, and the evidence of his touch.

Although Innes, 36, now claims his work is more gestural - he does not feel the need to deny his part in the work's creation - his earlier compulsion to rid the hand from the painting led to his experimenting with turpentine. By pulling a brush dipped in it down the canvas, he created Newman-like "zips", spiritual conductors between the top and the bottom of the canvas, where the turpentine had dissolved the paint. He added, then dissolved, patches of paint, removing them almost completely from the canvas, leaving strangely organic shapes behind, as with his 1991 "Quotations" works. Olive-green paint was almost washed away, leaving traces of pigments - yellow, grey, brown - streaking the canvas. His "Monologues", produced the following year, looked almost sedimentary, with Paynes Grey streaks rippling up some canvases, down others, making patterns like a beach at low tide, or a layered quarry-face. The effect of these simple - "unpainted" - works led to the re-entry of the figure, not in a physical way, but emotionally, through the fragility of the colours on the canvases, and gentle, yet slightly disturbing traces of paint left where the turpentine strokes had stopped.

The NatWest prize-winning "Exposed Paintings" are his most recent: blocks of colour thick and dense on the canvas, with one part washed away, eaten into, by the "unpainting". The traces of the turpentine's effect remain on the canvas, a trickle of pigment running from the lower corner of the solid colour rectangle, scattering the different colours that really comprise its hue.

Although each area of thought Innes moves through, such as the "Exposed Paintings", looks to the viewer much like a series, he says, "I don't work in series, I work sequentially. As soon as I have made something I always see the possibility of doing it slightly differently. You can only take a work so far, and when you hit that point it has to move on - it wouldn't be art unless it did."

Innes, whose "Exposed Paintings" toured from Birmingham to Berne, and who has another show in Dublin this summer and one in Kendal in the autumn, says the prize has made him feel more secure, allowing him to invest in his own work. "Painting is long-term. I make a great deal of work, and I edit a great deal of work out. A lot of work is not back to the drawing board but into the dustbin. I always see the possibility of going for the next step, changing something like the pigment or the colour, or the structure of the piece. It often causes dilemmas for curators who come to my studio and say, well what's wrong with that piece, and I say, it's not quite right."

While Innes is grateful for his prize and accepts that those who win such awards gain in prominence, the all-or-nothing principle in the nature of most does not appeal to him. The NatWest prize, however, offers pounds 26,000 to the winner, with each of the other 10 shortlisted artists receiving pounds 1,000 each. "The nature of this prize is that it's stressful, but not as stressful as others of its kind, because there's a show, there's some money, and last year a lot of people sold work, and one or two people got dealers," he says.

Having won the prize, how did Innes feel about going back this year as a judge, working with Marjorie Allthorpe-Guyton, director of visual arts at the Arts Council of England, dealer Anthony Mould, Byam Shaw School of Art's principal Alister Warman, and NatWest Group Art Collection curator Rosemary Harris? "It's very hard addressing one work after another, but it was quite interesting to see what 250 painters are doing in the country. Getting it down to 11 [the shortlist number] was hard work."

Jason Brooks, winner of a John Moores Painting Prize in 1997 (Innes won a similar John Moores award in 1993), is one of those on the shortlist; his large-scale meticulous portraits are up against the "blind" drawings of Claude Heath, the police cells and launderettes of Sarah Beddington, and the exceedingly Kiplingy paintings of Terence Haggerty.

Innes's own work is that of an alchemist. He pulls Naples Yellow, which glistens gold, out of a seemingly dense block of Paynes Grey, using only turpentine. He tricks the viewer through a series of complicated procedures that suggest he has used one technique, when he has used five others. He is a painterly Rachel Whiteread, dealing with traces of humanity through a seemingly abstract language that points to minimalism, when in fact it is organic and, in parts, random. I would conjecture that his magic is strong enough to secure him another viewing on the Turner Prize shortlist at better odds (last time he was shortlisted, in 1995, he was up against Damien Hirst on his second time around). Perhaps all that glisters is gold, after all.

`NatWest Art Prize': Lothbury Gallery, EC2 (0171 726 1642) Mon to 27 August; prize awarded 15 June. `Callum Innes': Irish Museum of Modern Art, Dublin (00 353 1 612 9900) 23 June to 12 September