Sticks & Stones: Linseed Oil
On one of painting’s most difficult and rewarding techniques
In our series Sticks & Stones, we take a deep dive into medium. Each installment features one of art history’s most significant materials—its history, evolution, and unusual uses. This week’s medium is linseed oil (explore the playlist).
For as long as people have painted, the issue of how to portray light has been at the form’s center. The story of painting has essentially been of the struggle between the opaque, mineral material of paint and the glowing sense of light artists hope to create. The appearance of inner luminosity can be mimicked, to a limited degree, by an artist’s placement of light and dark tones side by side. But it is ultimately dependent on the complex interactions between layered colors as outside light strikes them.
Oil paint is made by mixing finely ground pigment with a binding oil to help it adhere to the canvas or board. Linseed oil is a drying oil—it can polymerize into a solid form without changing other physical characteristics, such as color or texture. It can also be used as a painting medium—added to thick, mixed paint to make it more fluid, transparent, and glossy. When the amount of linseed oil exceeds the amount of pigment in the mixture being applied, it is considered a glaze. The introduction of linseed oil glazes was one of the most significant factors in moving oil painting forward.
Glazing creates a unique “shine through,” a luminous effect that is not obtainable by direct mixture of paint. One way of thinking about the way glazing functions is to imagine the glaze layer as a thin pane of tinted glass through which the painting is viewed. It subtly changes the color of the paint beneath it, but rather than creating a uniform color shift of the kind that mixed-in opaque paint would yield, the glaze layer interacts dynamically with the quality, angle, and amount of light that hits it. Light travels through the glaze and is reflected back off the opaque layer below, causing a luminous effect. Glazing provides an invaluable tool to painters in that it creates the glow necessary to paint certain tough subjects, like skin tones or diffused light.
Although in theory the technique is very simple, glazing can be a very complex undertaking. The glaze must be applied using a wide, soft sable-hair brush, with a very gentle touch. The underpainting—the layer of opaque ‘drawing’ below—is generally executed in bold contrast and allowed to dry before the glaze is laid on top.
One of the artists most known for his use of the luminous potential of glaze was Johannes Vermeer. Relatively little is known about the life of this master painter of the Dutch Golden Age; compared to other painters of his stature and influence, his personal life is inscrutable. Much of what we do know about him comes from his surviving paintings: a collection of contemplative interior scenes that seem to be set, for the most part, within a single room of his home in Antwerp.
A beautiful example of expert glazing can be found in Vermeer’s Girl with a Red Hat. The red hat, according to common practice for painting vibrant bright objects, was first ‘modeled,’ or drawn, with pure vermilion (a brilliant scarlet) and black. Over that layer, the lighter areas were glazed with a thin film of pure madder lake (a deep fuchsia), while the shadowed areas would be deepened with a thicker glaze of madder lake mixed with black or natural ultramarine. While some applications of glazing, such as painting vibrantly bright objects like the hat, have been tested and proven, it’s much more often that the process relies on the artist’s intuition. It can be quite difficult to anticipate how greatly a layer of glaze will alter the overall appearance of the finished work. One has to determine with extreme precision how thick or thin the glaze should be—too much or too little glaze can affect the stability of the paintings material surface, as well as its color. For this reason, glazing is usually confined to small, specific areas of a painted image. An example of this more spontaneous, instinctual kind of glazing can be seen in The Music Lesson—specifically, the complex shifts between pinks, blues, and oranges in the walls, boasting Vermeer’s confidence and competency in layering often incompatible colors.
A mastery of glazing allowed Vermeer to create images that glowed from within, filled with luminous skin tones, sun-dappled interiors, and lustrous fabrics. His surviving works, few that they are, continue to this day to provide insight and expertise into one of oil painting’s most difficult, most rewarding techniques.