We’re remarkably good at perceiving different surface textures, but find it harder to imagine them in two-dimensional images. While the overwhelming majority of paintings, at least until the twentieth century, consist of a paint layer on a flat ground, there’s nothing that requires the surface of the paint layer to be flat and smooth. But if all you look at are images of paintings, you generally won’t see their surface texture, where the artist has applied and shaped paint in thick layers of impasto, or incised into some of the layer in sgraffito. This article looks in detail at four examples where surface texture in the paint layer is important.

Arnold Böcklin’s unusual painting of Sirens from 1875 was made in tempera on canvas, with the ground and paint layers thin enough to let the texture of the canvas weave show through. This image was fortuitously taken with lighting that allows the texture to show.

Another famous tempera painting wasn’t painted on a textured ground, but is one of the earlier paintings to feature impasto as a technique.

The Wilton Diptych was painted on two small panels of oak wood in the final years of the fourteenth century. That wood was first assembled into the panels, then carved down from a thickness of about 2.5 cm (1 inch) to form an integral frame with a recessed painting surface. A smooth gesso ground was then laid on the wood before the gilded areas were laid onto it using thin sheets of gold leaf, and patterned using a range of punches.

Details of jewels and similar objects such as the white hart brooches were raised using thicker areas of lead white paint, to give the impression of enamelling. Coupled with mordant gilding, they mimic the three-dimensional form of jewels and act as point reflectors of light, sparkling as if they really were gems in the paint layer, as shown in the details above and below.

The finest strokes of paint seen here are less than 0.5 mm (1/50th of an inch) across.

From those early days of modern painting until the decline of ‘academic’ painting in the late nineteenth century, patrons, Salon juries and critics expected paint surfaces to be smooth and flat. But there were rebels.

Many of Rembrandt’s paintings from before 1650 have fairly conventional ‘finished’ surfaces, his monumental Night Watch being a good example. By about 1660, though, many of his paintings had quite rough surfaces that significantly alter their optical properties.

One of the best examples of Rembrandt’s use of texture in the paint layer is The Jewish Bride from about 1667, just a couple of years before his death. This is among his works studied by the Rembrandt Research Project.

In this detail, highlights on the sleeve and jewellery have been applied roughly, although it’s still a matter for speculation as to exactly how he achieved that. Lower down, on the red dress of the bride, the duller top layer of paint has been scraped through to reveal lighter lower layers. The end result is a painting that creates its visual effects as much by its surface textures, as by form or colour.

One of Rembrandt’s secrets that have been sought by so many since lies in how he was able to exploit surface texture in his paint. That is the ‘secret recipe’ which Maroger, Redelius, and others claimed to have discovered. Systematic analyses of Rembrandt’s paint layers by White at the National Gallery in London and the Research Project soundly rebutted the ‘secrets’ claimed. In the main, Rembrandt used linseed oil as his binder, occasionally using walnut oil as well, and just once poppy seed oil.

In some passages the oil had been thickened by heat treatment, but this was by no means widespread. Traces of pine resin found in some samples may have been introduced during retouching, and don’t appear to be a feature of Rembrandt’s impasto work; neither is there any evidence that he added wax to his oil paint to give it body, as some had asserted.

As you might expect, JMW Turner was another such rebel.

For example, in his Seapiece with Fishing Boats off a Wooden Pier, a Gale Coming In, possibly from as early as 1801, Turner made extensive use of sgraffito, made using a knife, brush handle, or even his fingernails for all we know.

Later that century, Vincent van Gogh developed a more radical approach, in his initial version of Wheat Field with Cypresses from 1889, the year before his death.

It’s possible that he completed this painting in a single sitting, as this seems to have been intended as an oil sketch for a more finished version which he painted later that summer.

The detail above shows the tops of the wheat towards the lower left of the field, in the foreground. Over his initial thin layers of paint, van Gogh laid thick gestural strokes of highly chromatic paint, orientating those strokes according to the object they show. In the golden yellow of the wheat there are blues and greens, mostly showing through from his underpainting, with superimposed impasto of pale straw, ochre, and pale greens.

This detail, taken from the edge of the wheatfield at the lower right corner of the painting, shows three distinct areas of brushwork: the diagonal strokes forming the standing wheat, swirling loops to form the grasses and weeds below, and shorter marks forming a more random pattern for the heads of the wheat in the upper section.

At the centre of the canvas, from where this detail is taken, impasto blue and white have mixed with the green and yellow of the fields below. This shows that much of the painting was painted wet on wet, either in the same session or on consecutive days. Some of the darker green at the right may have been painted later, onto paint that had by then become touch dry.

An X-ray image of the whole painting shows in white those passages likely to contain the most lead white, and some other pigments which are most radio-opaque. This also reveals the pattern of brushstrokes well.

With the introduction of acrylic paints in the latter half of the twentieth century, painters have been able to apply even heavier impasto, and some have used this to paint what are in effect reliefs.

This is why so many paintings have to be seen in the flesh, up close, and in the right light for their full appreciation.