The ground is the preparatory layer applied to a painting support before painting. From medieval gesso to modern acrylic primer, learn its history, types, and function.
When the J. Paul Getty Museum examined Willem de Kooning's Woman-Ochre (1955), they found something most viewers never think about. The painting's background was not just bare canvas with paint on top. Between the canvas support and the oil paint, there was a layer of chalk, zinc white, and lead white. De Kooning had left this preparatory layer visible throughout the background behind the figure. The ground was not just a base coat. It was part of the painting's visual effect. This layer, which most people never notice, is the ground, and it is one of the most important decisions a painter makes before picking up a brush.
In visual arts, the ground (sometimes called a primer) is a prepared surface that covers the support of a painting and underlies the actual paint. The ground sits between the support and the paint layers. Its main purposes are to block chemical interactions between the paint and the support, to provide a surface with the right texture and absorbency for painting, and to create a consistent color that affects how the paint appears on top of it. The ground is applied after sizing, which seals the support, and before the paint layers.
This entry covers the history of grounds, the different types used in different periods and painting traditions, how grounds affect the appearance and longevity of paintings, and how to choose a ground for your own work.
A ground layer, or primer, typically follows the size layer in an easel painting. The size seals the support, preventing paint and ground from penetrating into the fibers of canvas or the pores of wood. The ground then sits on top of the size and provides the surface the painter actually works on.
Grounds serve multiple purposes. They create a surface with the right level of absorbency for the paint. For oil painting, the ground must be slightly absorbent so the oil binder can grip the surface, but not so absorbent that it sucks the oil out of the paint and leaves the pigment underbound. For egg tempera, the ground must be highly absorbent, because tempera bonds by sinking into the surface rather than forming a film on top of it. For acrylic painting, the ground can be more absorbent because acrylic binder adheres well to porous surfaces.
The ground also provides a consistent color that affects how paint appears on top of it. A white ground makes oil and acrylic colors appear brighter and more luminous because the white reflects light through the paint layers. A toned ground, whether gray, brown, or red, provides a mid-tone that the painter can work both up toward light and down toward dark, which is faster and more efficient than starting from white. The MITRA (Materials Information and Technical Resource for Artists) guide to grounds and primers provides detailed technical information about how different grounds affect paint aging and conservation.
The earliest grounds were made for panel painting. A mixture of gesso (calcium sulfate in Italy) or chalk (calcium carbonate in northern Europe) bound with animal glue was used to prime wooden panels. The technique was known from antiquity and described by Theophilus Presbyter in his 12th-century treatise On Divers Arts. Italian painters used a two-layer system: a coarse lower layer called gesso grosso, made with coarse gypsum particles, followed by a finer upper layer called gesso sottile, made with fine gypsum slaked in water. The gesso sottile produced a smooth, opaque, reflective surface that could be sanded and polished to an ivory-like finish. The National Gallery London's glossary on gesso documents these historical formulations.
In northern Europe, chalk grounds bound with animal glue were standard. The distinction between southern (gypsum) and northern (chalk) grounds is one of the technical differences that art conservators use to distinguish paintings from different regions. Northern chalk grounds tended to be slightly less hard than Italian gesso grounds, producing a different surface quality.
Coloring grounds is a very long tradition. In the 2nd century, Galen described the use of glaze to reduce the brightness of gesso. In the Medieval and early Renaissance period, thin coats of paint called imprimatura were used for the same purpose. Unfinished Michelangelo works suggest that he used a green underpaint for flesh tints. Leonardo da Vinci recommended using a white ground for transparent colors, suggesting that the typical ground in his time was colored. Venetian painters used darker grounds. Titian used brown or brownish-red grounds. Florentines preferred light tones, gray in the Vasari period. Rubens employed either ground charcoal with white over a gypsum base or solid gray tints.
The "Down to the Ground" project, a collaboration between the University of Amsterdam and Delft University of Technology, has built the most extensive database of colored grounds in Netherlandish painting from 1500 to 1650. The project identified over 830 records and found that most Netherlandish paintings employed double grounds: a colored or white first layer and a neutral-toned second layer. On canvas, the first ground was typically earth-based and oil-bound, composed of iron-oxide reds, brown and yellow ochres, or clays. These mixtures provided flexibility and could be applied thinly, allowing canvases to be rolled without cracking. A lighter upper ground, often light grey or light brown, provided a neutral mid-tone for modeling form and light. Read the DttG research on common ground types in the Netherlands for detailed findings.
By the 17th century, oil grounds with added litharge atop vegetable glue were used, though combinations of gypsum and glue were still preferred. Many painters started using red or brown pigments for their oil grounds. Oil grounds created a smooth, non-absorbent surface that was the traditional ground for oil painting on canvas. They were more flexible than glue gesso and more compatible with oil paint. However, they were slow-drying, sometimes taking two weeks or more to cure.
The 19th century witnessed the birth of pre-primed canvases. White and pale colored emulsion grounds, absorbent grounds, and other formulations became available from manufacturers, consisting of many different materials including glues, egg, oils, clay, and starch. By the 1950s, titanium white and zinc white had mostly replaced lead white in commercially available pre-primed supports. Today, acrylic dispersion pre-primed grounds are the most common among contemporary painters.
Alkyd grounds, made from oil-modified alkyd resin, have been in use since the 1960s. They dry faster than traditional oil grounds and use titanium white for color. Modern "oil ground" products are actually alkyd-based, since genuine lead-based oil primers are no longer used due to health hazards.
The most common ground used by contemporary painters. It is a mixture of acrylic polymer emulsion, calcium carbonate, and titanium dioxide. It is flexible, dries quickly, and adheres to almost any surface. It serves as both sizing and primer, eliminating the need for a separate glue size layer. However, it is less absorbent than traditional gesso, making it unsuitable for egg tempera. See our entry on gesso for details.
Made from animal glue (usually rabbit skin glue), chalk or gypsum, and white pigment. Applied in multiple layers, sometimes as many as 12 to 20 for icon painting, and sanded between layers. Very absorbent, making it the correct ground for egg tempera and water gilding. Should only be applied to rigid supports, as it will crack on flexible canvas.
Consists of titanium white pigment bound in alkyd resin (historically, lead white in linseed oil). Applied over a glue size on canvas. Creates a smooth, non-absorbent surface ideal for oil painting. More compatible with oil paint than acrylic gesso, but slow-drying. The traditional choice for professional oil painters who want the surface quality of old master paintings.
Some painters use a two-layer ground system. A first, darker layer fills the texture of the canvas and provides bulk. A second, lighter layer provides the working tone. This system, common in 17th-century Netherlandish painting, offers both technical and optical advantages: the darker first ground fills the canvas weave, while the lighter upper ground provides a neutral mid-tone for modeling.
The ground affects the painting in ways that are not always visible immediately but become apparent over time. A ground that is too absorbent can cause the paint to look matte and underbound, because the oil or acrylic binder is drawn into the ground rather than staying in the paint layer. A ground that is too non-absorbent can cause the paint to slide off or fail to adhere properly. The flexibility of the ground must match the flexibility of the support: a rigid gesso ground on flexible canvas will crack as the canvas expands and contracts with humidity changes.
The color of the ground affects the overall tonality of the painting. Painters who work on white grounds tend to build up dark areas first and add lighter passages on top. Painters who work on toned grounds can work both up and down from the mid-tone, which allows for faster coverage and a more unified tonal effect. The ground color can also show through thin paint passages, creating optical effects that are part of the painting's final appearance. De Kooning's Woman-Ochre is a documented example of this, where the ground layer is deliberately left visible.
The ground is applied to the support, the physical surface of the painting. The most common ground material is gesso, which has its own entry. A thin, colored layer applied on top of the ground is called an imprimatura. The ground must be compatible with the binder used in the paint, whether that is oil, acrylic, or egg tempera. For more on the surfaces that grounds are applied to, see our entries on canvas and panel. And for a practical guide to surface preparation, read our post on oil painting techniques.
Grounds are usually invisible in finished paintings, but you can see their effects. The luminous, smooth surfaces of Renaissance panel paintings at the National Gallery in London or the Uffizi in Florence are the result of carefully prepared gesso grounds beneath tempera and oil. The warm, unified tonality of Rembrandt's paintings at the Rijksmuseum comes partly from the colored grounds he used. And in modern paintings like de Kooning's work at the Getty, the ground can be an active part of the composition.
For more on the layers that make up a painting, read our entries on support and gesso, or explore our post on oil painting techniques to see how ground preparation affects the painting process.
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