Women War Artists, Imperial War Museum, London

They also serve, who only stand and paint

For thousands of years, war has been men's affair.

The lot of women was to wait and grieve, a role superbly summed up in a work called Pale Armistice by the now 80-year-old British artist Rozanne Hawksley. At first it looks like a wreath that might be laid on any war memorial, except that it's bleached of all colour, bone-white. On close inspection, you see that the wreath is composed of dozens of white kid gloves, standard women's attire in the years of the First World War. Closely interleaved, these phantom feminine hands seem to plead, stroke, clutch, pray, despair. Quietly, without show, they articulate the behind-doors suffering of millions.

That war was a turning point for women artists. The first official war art scheme was set up by the British government in 1916, and although only four of the 51 artists commissioned were women, and of these one dropped out and three had their work rejected, the newly established Imperial War Museum also commissioned nine women artists to record "women's war work". None was allowed access to the the battlefield, but some, such as Olive Mudie-Cooke, found themselves near the front line working in hospitals and ambulance units.

Mudie-Cooke's A VAD Convoy Unloading an Ambulance Train at Night After the Battle of the Somme is a dim brown watercolour with a pungent sense of actuality. A similarly modestly-sized work by the same artist in brown ink, Sanctuary Wood, makes a daring statement, for 1920, in its forlorn study of the remains of a spinney, still blasted and leafless two years on.

Women War Artists, which includes works being shown for the first time, is predictably stronger on women as eyewitnesses and recorders than as participants, although you could make a case for the latter in the work of Dame Laura Knight. Her hyper-realist oil of 1943, Ruby Loftus Screwing a Breech-ring, is pure government-commissioned propaganda, succeeding brilliantly in making a heroine of young Ruby, a former shop assistant now toiling in a Royal Ordnance factory turning out Bofors guns. With her hairnet fashionably knotted into a turban, her clean-scrubbed face gleaming with concentration, she is fully in charge of the machinery she operates, with its whirring blade, flying sparks and puddles of oil.

There is personal participation, too, in Knight's giant fantasy canvas The Nuremberg Trial, which shows the now familiar courtroom benches surrounded by bombed-out buildings, some still aflame. "In that ruined city death and destruction had to come into the picture", she said.

A more harrowing marker of that time, though, is Doris Zinkeisen's Human Laundry, Belsen, April 1945, which contrasts the plump, crisply uniformed medical staff with the naked shadows of humanity they attend to on each bed. The scene is a requisitioned stable, and though the floor is clean scrubbed, tufts of straw still stuff cracks in the windows.

Yet few of the images in this show live up to the apocalyptic visions of John Piper and Paul Nash. Nor does it even attempt a definitive history of changing attitudes to gender in wartime. You'd never guess, for instance, from this selection, that young women now regularly defuse bombs in Afghanistan. The work of the Dame Lauras, for good or ill, is now done by the moving image.

To 8 January 2012; admission free