The paintings of Johannes Vermeer (1632–1675) were quickly forgotten after his death, and his art fell into obscurity. Since their rediscovery from 1860, they have become increasingly popular, recognised for the masterpieces they are, and one – The Girl with a Pearl Earring – has become one of the best-known works of art in the world. In this article I consider how Vermeer came to create such exceptional paintings.

Since his rediscovery, Vermeer and his relatively few and thoroughly modest surviving paintings have been the subject of a great deal of research. This has shown that his materials and techniques are, in the main, fairly unexceptional by contemporary standards. At this time in the Dutch Golden Age, easel paintings were hugely popular with collectors, and as a result he may well have bought his canvases stretched and ready to paint.

He bought his pigments from local suppliers, pharmacies in particular, and had a particular fondness for ultramarine, then extremely expensive. He was also one of the last great exponents of the use of lead-tin yellow, before it was forgotten about. These are all valuable and interesting details, but don’t explain his art.

Between about 1660 and 1668, Vermeer painted a series of indoor figurative works ranging from portraits such as The Girl with a Pearl Earring, through genre scenes like The Milkmaid, to what is almost certainly allegory in The Art of Painting. They are each remarkable for their use of optical effects, in that they appear to be the first and only paintings made before the late nineteenth century in which edges and objects are intentionally blurred.

This is perhaps most immediately obvious in The Girl with a Pearl Earring, from around 1665. Seen even closer up in the detail below it’s obvious that Vermeer has softened most of its edges to some degree, even on highlights such as the white reflections on the pearl itself and the girl’s eyes.

Vermeer accomplished this by applying fresh wet paint to previous paint which wasn’t yet touch dry, sufficiently wet still to allow controlled mixing at its edge. The next major painter to have used this technique as extensively is Anders Zorn, working more then two centuries later, after another visual revolution had introduced viewers to the optical effects of photographs.

One of the best examples of Vermeer’s systematic use of blurred edges is also one of the first of his surviving paintings to use this technique: The Milkmaid, from about 1660.

A woman servant, kitchen or house maid, is pouring milk from a jug, beside a tabletop with bread. In the left foreground the bread and pots rest on a folded Dutch octagonal table, covered with a mid-blue cloth. A wicker basket of bread is nearest the viewer, broken and smaller pieces of different types of bread behind and towards the woman, in the centre. Behind the bread is a dark blue studded mug with pewter lid, and just in front of the woman (to the right of the mug) a brown earthenware ‘Dutch oven’ pot into which the milk is being poured. An ultramarine blue cloth (matching the woman’s apron) rests at the edge of the table.

The woman, seen in three-quarter view, wears working dress: a stiff, white linen cap, a yellow jacket laced at the front, a brilliant ultramarine blue apron, and a dull red skirt underneath. Her right hand holds the handle of a brown earthenware pitcher, which she supports from below with her left hand. Her work sleeves are pushed up to lay both her weathered forearms bare to the elbow. Her strong-featured face and eyes are cast down, watching the milk as it runs into the pot.

At the left edge is a plain leaded window which casts daylight onto the scene. One of its panes is broken, leaving a small hole. Hanging high on the wall on the left is a wickerwork bread basket and a shiny brass pail. Immediately above them is a small dark form which could be a painting in a deep, dark wooden frame, at the top edge of the picture. The wall behind is white and bare apart from a couple of nails embedded towards its top, and several small holes where other nails once were. At its foot, at the bottom right, five Delft tiles run along the base. In front of those is a traditional foot-warmer, consisting of a metal coal holder inside a wooden case. The floor is dull red, with scattered detritus on it.

The painting is light and simple, showing the servant peacefully preparing food in a well-lit corner of a kitchen. The bread on the table is finely textured with seeds, the glaze on the pots glistening in the light, contrasting with the smooth fabrics and flesh of the woman. The edges of her forearms are soft, suggesting movement. Patterns of fine cracks in the paint outline a rough rectangle on the bare wall which may reflect pentimenti (alterations), and there are faint darker marks at the base of the wall just above the tiles, which may also be pentimenti.

Further examination of the painting has revealed that there was originally a large map covering most of the back wall, which was later painted over to leave the wall almost bare. At the foot of that wall, Vermeer had originally painted a basket of clothes, but this too he painted over later, leaving just the foot-warmer and Delft tiles. A small depression in the paint just above the woman’s right hand marks the vanishing point used for its linear perspective projection, a traditional technique since the Renaissance.

Look more closely now at the edges of the woman’s figure.

They’re sharpest around the woman’s left shoulder and upper arm, and soften as you look away towards her hands and the pitcher. Highlights on that pitcher and the pot below it are also decidedly blurry. These are consistent with the use of blurring to suggest movement, and for photographic depth of field, a focus effect which didn’t become widely known until after the advent of photography.

Bread and other objects on the table in front of the woman also show controlled use of blurring, most obviously in the highlights on the wicker basket.

Turning to Vermeer’s slightly later Woman Holding a Balance from around 1662-5, its focus is even softer. There is a clear edge hierarchy, in which the edges of the tabletop in the centre of the canvas and the woman’s left hand are the crispest, and those further from that focus of the image are noticeably softer.

Similar effects are seen in Vermeer’s much better-lit A Young Woman with a Water Pitcher from the same period. Here the central focus is in the upper chest of the figure, where the edge between the split in her white mantle and the underlying deep ultramarine clothing is crispest, and the reflections on the pitcher and bowl are quite blurry. So too is the window, which might indicate movement.

In Vermeer’s late The Art of Painting from about 1666-8, the focus of sharpness is again slightly away from the geometrical centre of the canvas, in the woman holding a wind instrument, as shown in the detail below. The high tonal contrast between the marble tiles on the floor is softened in the foreground, and sharpens deeper into the picture.

Recently, several attempts have been made to explain how Vermeer came to use blurring and edge hierarchy so successfully. One story which has gained some traction is that he used optical devices such as a camera obscura to lay out the forms within each of these scenes, a theory which has been repeatedly claimed by David Hockney among others. Most recently, though, it was realised that was insufficient to explain all the optical phenomena modelled so well in these paintings, and it has been proposed by Hockney and Tim Jenison that the artist coupled a concave mirror with another mirror, a system which took Jenison five years to develop and test.

It’s perhaps unsurprising that there’s no evidence whatsoever that Vermeer possessed or used a camera obscura or other optical device, although he was a close friend of the pioneer lens maker Antonie van Leeuwenhoek.

Whether Vermeer arrived at his innovative treatment of edges and blurring by trial and error, close observation, or optical experiment appears irrelevant to his art. The fact is that, ever since people have been used to seeing blurring in photographs, his paintings have appeared those of true genius. Maybe he should also be credited as the inventor of what is now termed bokeh?

Finally a cultural tragedy: there are few enough surviving paintings by Vermeer in the world, but one, The Concert from about 1663-66, was stolen from the Isabella Stewart Gardner Museum in Boston, MA, on 18 March 1990, and remains unrecovered. What sort of person would deprive the world of such art?