Aman stands beside a tree. There's something a little too intense about this bloke. If I passed him on a country walk, I'd give him a wide berth. The light's wrong, too. His shadow stands beside him, falling on the sky. The shadows cast by the tree also blotch the clouds. Not a real tree, then, not real clouds, but a stage-prop tree against a painted backdrop. The man is an actor on a stage, standing in raked theatrical light, watching some piece of business we can't see. It all looks a bit old-fashioned and stilted, fag-end repertory tour. He's a failed, forgotten leading man from another age. This is The Conman, by Belgian painter Michaël Borremans.
Borremans says that if he hadn't been an artist, he would have liked to have been an actor. There's a frustrated actor in every confidence trickster - and how much of the con-artist is there in the painter, who makes you believe in things that aren't there or could never be?
Borremans' first British show opens tomorrow at Parasol Unit, a new "not-for-profit foundation for contemporary art" in London. The show itself is called The Performance, to underline a certain theatricality. It includes a painting, also called The Performance, of a box hidden under a cloth. The box is reflected in the brown, varnished surface on which it stands. What is in the box? A surprise, perhaps. There could be a conjurer's rabbit in there, chocolates, a severed head or a bomb. The mind runs riot. No one will ever whip the cloth away.
Borremans' exhibition has travelled from Ghent, the artist's home town, and will continue to Dublin. Simultaneously, a show of the artist's drawings is travelling from Europe to the US. Borremans trained as an etcher and draughtsman, and only later turned to painting. His art is peculiar, sometimes self-consciously diffident and understated, sometimes bordering on the surreal. Sometimes his paintings are like scenes from old movies that you think you remember but never really saw, his drawings storyboards for unwritten scripts.
Some of his portraits, such as The German (a man seated at a table playing with little red balls in his hands; at first I took these for a rosary, or cherries, but they are those billiard-ball atoms and molecules scientists use in lectures) or The Marvel (a portrait of an anonymous woman with a 1930s hairdo and blouse, borrowed from an old illustration from a dressmaking pattern book) are reminiscent of the earlier work of Luc Tuymans. They have the same introspection, a similar sallowness and sense of weariness - but their technique and handling is different.
What Borremans and Tuymans might share (apart from Flemish origins) is a desire to paint psychic states, a reality full of fault-lines and disjunctions. Atmosphere, touch, a quality of light, surface and scale have as much a part to play in this as drama, subject matter, action. Paintings don't need to be exciting or overtly dramatic (nor, you might say, do novels). Some of Borremans' paintings depict bizarre situations. They are better when their strangeness is understated. Most of his painted figures are in themselves expressionless, as much as they might also be characterless, however unlikely some of the situations in which they find themselves might be.
Four women find themselves sunk up to their midriffs in a tabletop, or in a tank of black oil. They look down, with something more akin to mild curiosity than fear or surprise. They wear nice frocks and have the kinds of hairdos women wore 60 years ago, and old women still wear now. It is as if they were somnambulists, half-sunk in the past, or some inexplicable dream. This is all a bit of a conundrum. Perhaps it is a metaphor for painting itself, and how it reveals and obscures things.
In The Pupils, three young men in factory overalls appear to be working on some kind of production line. Each bends over a supine figure. I took these operatives for apprentice dentists or trainee cosmetic surgeons at first, but that's not right. All the figures look alike. Why is it that a thread-like strand of white, like pure light or tears, falls from their eyes into the upturned eyes of the faces they lean over? What passes between the eyes in this painting might be reciprocated between the painting and the viewer. The painting is also a depiction of an activity that looks like work. We call a painting a work, too, and we work at it when we look.
Somehow, the atmosphere here manages to be gentle and sinister. This is often true in Borremans' art. Feet are splayed about a basket of flowers, like the base of a porcelain figurine, all painted with a frothy touch, as if he were painting this object with slippery ice cream. The aggressively spiky leaves of a pot-plant are contradicted by the soft-focus shadows that blur against the wall behind. All this should be kitsch, but isn't. Instead, it is unnerving.
Borremans' figures, preoccupied in what they are doing, are oblivious to our presence. No one ever returns the viewer's gaze. Their apparent indifference to us is matched by their self-consumed inexpressiveness, as they go about their inexplicable tasks. The expressionless can have great weight in painting, as in performance, theatre and film. This emotional blankness can also make you want to scream. Looking at some of Borremans' mystifying scenes is a bit like watching something through a layer of soundproof, bulletproof, one-way glass. This, perhaps, is what the past is like.
The colour and light hark back to some indefinite period between the 1930s and 1950s, too - to a time of low-watt lightbulbs, joyless murky greens and off-grey domestic decor, faded duotones and dull magazine reproductions and illustrations. The period is one the artist's parents would know better than he would (Borremans was born in 1963), except through old movies, photographs, reminiscences, the physical and psychological traces of the near past that persist into the present.
The past is forever making its presence felt in Borremans' paintings and drawings. This is partly a matter of art historical and stylistic quotation, and in part a confusion of past and present by way of out-of-date clothing, stilted gestures. At times he borrows the kind of alla prima brushwork and shorthand Manet used in his sketches, or a bit of blue trim on the Conman's jacket from Goya. For figurative painters, this sort of thing is unavoidable. It is impossible for anyone to paint a figure or object without reference to the past. Technically, painting does not advance, and there are only so many ways to depict drapery or highlights, hair or leaves. The painting Disposition depicts the open pages of an art book, with a full-page reproduction of a 17th-century painting, seen at an angle. Borremans has painted a slick of light reflected on the glossy page, which appears to explode from the painted jug in the reproduction, like an apparition or an eruption of ectoplasm, or the present flaring on to the past and changing it.
Borremans keeps reminding us these are figures, not people, and that the painted are just that: painted, their inner lives and acts an illusion, as well as an allusion to something else, whatever that might be: autobiography, history, fantasy, an enigma. What Borremans withholds from us is a story. He gives us actors and situations. We know the story is in there, just as we know there's something in that box he painted and covered with drapery. It was but one more attempt to paint a hidden object, which is one of art's enduring subjects.
· Michaël Borremans: The Performance is at the Parasol Unit, London N1, from tomorrow until June 30. Details: 020-7490 7373. Adrian Searle is in conversation with Michaël Borremans at the Prince Charles Cinema, London WC2 (020 7494 3654), on May 16.