They must have been easily fooled in the 17th century, you think when you first look at the purportedly eye-fooling art of Cornelius Gijsbrechts. Gijsbrechts made a career of painting trompe l'oeil as court painter to the rulers of Denmark from 1688 to 1672 - the only period of his life when anyone knows anything about him. On the tricksy level you expect of trompe l'oeil - painting intended to deceive - his paintings don't deliver. His still lifes look like painted still lifes, however much you squint.
Yet there is something stranger and gloomier going on here than a picture puzzle. As you scrutinise paintings of dead animals hanging on bare walls you begin to think something is rotten in the state of Denmark. Illusionistic painting was used in the 16th and 17th centuries to multiply the world's riches. But Gijsbrechts' court paintings are a claustrophobic dead end: every way you turn you come to a wooden wall.
He paints dead game, guns, money bags, letters, combs, in shallow relief on wooden shelves or glass cabinets. He spent a lot of time getting wood right. Gijsbrechts paints the shallow perspectives of his closed spaces so immaculately that you do start to imagine you're looking into a real space. Yet the objects in this space - a lobster, a royal letter whose three-dimensional solidity is belied by squiggles for writing - are obviously not real, as if the objects were less real than their surroundings, the people of the court less real than the architecture that confines them.
The more you study the trickery of Gijsbrechts' art, the more you are lured into little lies. No painting is a total illusion. Each one acknowledges its trickery, only to throw in a cunning illusion just when you think you're being respected. His cut-out life-sized painting of an easel is uncanny - however much you clock it as trickery, there's something else to confuse you. Are those holes in the wooden frame real? Oh no... but the shelf is real, right? Sometimes he adds real metal hinges or real wood next to fake. Always the effect is melancholy - all this effort for a lie.
Gijsbrechts's masterpiece is a painting of the back of a canvas - the frame, the bare canvas, even a number pinned to it in perfect relief. It's a painting of nothing but the mechanics of painting, a blank facade, behind which Gijsbrechts the mountebank vanished from the Danish court and from history, in 1674 or maybe 1675, never to be heard of again.
