Jacob van Ruisdael, 'A Bleaching Ground in a Hollow by a Cottage', probably 1645-50

The bright, white gash in the grassy bank on the right is one of the first things to catch our eye in this picture. Though it represents a split in the turf covering a dune, exposing the sand underneath, it also looks like a splash of bleach has stained the landscape white, and that is the subject of the painting.

In the seventeenth century, the bleaching fields of Haarlem, where Jacob van Ruisdael was born, were considered to be the best in Europe. The material worked on was linen, which was far more important than cotton as a fabric for making shirts, underclothes, bedsheets and table cloths. It also produced the incredibly long, fine threads used to make lace, for which the Low Countries were famous. But to fetch the highest prices, linen, which was naturally a dull beige colour, needed to be bleached white.

The process took place in spring and summer to maximise the amount of sunlight. First the linen was steeped in lye, a bleach made by soaking wood ash, and then, for about a week, it was regularly doused with a stronger solution which was heated to boiling point. The cloth was next soaked in buttermilk for five or six days, and finally spread on the grass and kept damp for however many days or weeks it took for the sun to complete the bleaching effect. The whiter the linen, the more valuable it was.

The flat fields and ready water supply in the rivers, canals and ditches around Haarlem were ideal for this process and van Ruisdael painted several landscapes which featured bleaching. This one was probably painted in the late 1640s before he left Haarlem to set up his studio in Amsterdam. Most of those views are more panoramic, looking out across a flat open landscape towards the town. In them, the strips of linen become part of the landscape and the figures are reduced to tiny dots in the fields.

This is a far more enclosed view of a much smaller set-up, apparently located among the large sand hills to the west of Haarlem. A family seems have made a bleaching works just below their cottage. One man stands knee-deep in a ditch full of water, dunking the material with a stick. Another lays it out in strips on the bank next to him, while a woman appears to be overseeing the work.

That sense of enclosure – a scene tucked away in the dunes and viewed from behind a tree – gives us the feeling that we are peering into a private world. The dark, gloomy sky helps to build the atmosphere and adds a touch of irony and sympathy. This was a hard life, dealing with caustic substances, and it depended on sunny weather. Rain clouds were the last thing the bleachers would have wanted to see.