Ground (art)

In visual arts, the ground (sometimes called a primer) is a prepared surface that covers the support of the picture (e.g., a canvas or a panel) and underlies the actual painting (the colors are overlaid onto the ground). Occasionally the term is also used in a broad sense to designate any surface used for painting, for example, paper for watercolor or plaster for fresco.^[1]

The main purposes of the ground are to block chemical interactions between the paint and the support and to provide desired texture for painting or drawing.^[1]

The ground is also used to highlight the colors,^[1] and its color and tone affect the appearance of paint levels above, therefore the painters might have individual preferences for the color of the ground: 19th century artists, especially the impressionists, preferred the white ground (first used by J. M. W. Turner^[2]), while Rembrandt preferred brownish tones and Poussin the red ones.^[3] The oil painting becomes more transparent with age, so to avoid a gradual brightening of the picture, a pale beige color of ground is considered neutral.^[4] White ground provides the greatest freedom of choice for colors, while colored grounds reduce the color range and force the use of more opaque paint application.^[1]

For paintings on panels, gesso is typically used as a ground; on canvas the ground can be yet another (inert) paint layer.^[5][3] Two layers are occasionally applied, forming a double ground.^[3] On canvas, the ground is typically applied after sizing (typically rabbit-skin glue). Although it is possible to paint on the sized canvas directly, without any ground at all,^[6] size is not a replacement for ground, as it is not intended to form a level surface for painting, its purpose is to simply fill pores and isolate the canvas from the overlaying paint.^[7]

Oxford Companion to Art lists the following requirements for the good ground:^[1]

• durability and resistance to flaking off or cracking;
• consistency and even tone across the surface;
• not being too smooth, so it can hold the pigments;
• not being too rough, so it does not impede the painting process;
• luminosity and reflectivity are needed for painting with most pigments, except the very opaque ones;
• low absorbance;
• the ground must be lean.^[2]