An excerpt from Vermmer The Complete Works by Arthur Wheelock
Vermeer employed many devices beyond his expressive use of light, color, and perspective to extend the meanings of his scenes. In a number of works he included objects imbued with symbolic associations. Paintings within his interiors frequently provide commentaries on the scene transpiring before them, as, for example, the Last ludgment hanging within Woman Holding a Balance, or the painting of Cupid holding aloft a card in A Lady Standing at the Virginal, a reference to an image in Otto van Veen's popular emblem book, Amorum Emblemata, 1608, that admonishes the reader to have but one lover. Vermeer, in fact, frequently painted figures playing music, exploring in these works themes of love and harmony so often associated with musical instruments. Similarly, he used maps, letters, pearls, and water pitchers as focal points within his compositions because their symbolic associations were fundamental to the meanings he wished to infuse into them.

Vermeer's paintings from the late 165Os and 1660s are characterized by a number of stylistic elements, including a seemingly naturalistic flow of light; subtly nuanced colors; carefully conceived spatial arrangements achieved through a sophisticated awareness of linear perspective; and, above all, an understanding of the expressive qualities of paint. He mastered the use of glazes, exploiting their translucency to give depth and resonance to his colors. He perceived the forceful power of thick impastos to create textural effects and compositional emphasis. He also used uncomventional techniques, for example, gold to accent a brass nail on a chair in A Woman Asleep, and sand mixed with his paint to emulate the the broken surface of red-tile roofs in the View of Delft.

As an artist: intent upon discovering the secrets of the visible world and finding ways to convey them in his works, it is not surprising thar Vermeer also exploited effects seen in a camera obscura. This fasclnating optical device operates much like a box camera. It creates an image by allowing rays to enter through a small opening, which can be fitted with a focusing tube and lens. The rays are then projected onto a wall or, in the case of a portable camera obscura, onto a ground glass opposite the aperture. This device opened a new range of expressive possibilities that Vermeer often used to give his images a heightened sense of immediacy. He discovered, for example, that in a camera obscura unfocused accents of light reflecting off shiny surfaces created diffused highlights that he could translate into paint. He then used these effects in a variety of ways, to suggest the flickering reflections of water on the sides of a boat in View of Delft, the freshness of newly baked bread in The Milkmaid, or unfocused foregrounds in small, intimate paintings like The Lacemaker or Girl witb the Red Hat.