Casein, or “cheese painting,” is a medium in which pigments are tempered with the gluey curd of cheese or milk precipitate. For handling, an emulsion of casein and lime is thinned with water. The active element of casein contains nitrogen, which forms a soluble caseate of calcium in the presence of lime. It is applied in thin washes to rigid surfaces, such as cardboard, wood, and plastered walls.
Matisse, Henri: Le Luxe IILe Luxe II, casein painting by Henri Matisse, 1907–08; in the Statens Museum for Kunst, Copenhagen.Courtesy of the Statens Museum for Kunst, Copenhagen
Casein colours dry quickly, although lighter in tone than when first applied. Since they have more body than egg-tempera paints, they can be applied with bristle brushes to create impasto textures not unlike those of oils. Casein paints were used in ancient Rome. They are now available ready-made in tubes and have been used by such modern artists as Robert Motherwell and Claes Oldenburg.
Casein is also an ingredient of some charcoal and pastel fixatives and was a traditional primer for walls and panels. Synthetic mediums
Synthetic mediums, developed by industrial research, range from the Liquitex fabric dyes used on canvas by U.S. abstract painter Larry Poons to the house enamel paints employed at times by Picasso and Jackson Pollock.
Riley, Bridget: FallFall, by Bridget Riley, 1963; in the Tate Gallery, London.Courtesy of the trustees of The Tate, London
The most popular medium and the first to challenge the supremacy of oils is acrylic resin emulsion, since this plastic paint combines most of the expressive capabilities of oils with the quick-drying properties of tempera and gouache. It is made by mixing pigments with a synthetic resin and thinning with water. It can be applied to any sufficiently toothed surface with brush, roller, airbrush, spatula, sponge, or rag. Acrylic paints dry quickly, without brush marks, to form a matte, waterproof film that is also elastic, durable, and easily cleaned. They show little colour change in drying, nor do they darken in time. While they lack the surface textural richness of oil or encaustic, they can be built up with a spatula into opaque impastos or thinned immediately into transparent colour glazes. Polyvinyl acetate (PVA) or synthetic gesso is applied for priming, although it is claimed that acrylic paints can be safely applied directly onto unprepared raw canvas or cotton. The wide range of intense hues is extended by fluorescent and metallic pigments. Polymer paints are particularly suitable for the precise, immaculate finish demanded by Op art, Minimalist, and Photo-realist painters such as Bridget Riley, Morris Louis, Frank Stella, and Richard Estes. Other mediums French pastels
French pastels, with the sharpened lumps of pigment used by Ice Age artists, are the purest and most direct painting materials. Pastel pigments are mixed only with sufficient gum to bind them for drying into stick molds. Generally, they are used on raw strawboard or on coarse-grained tinted paper, although vellum, wood, and canvas have been also employed. These colours will not fade or darken, but, since they are not absorbed by the surface of the support, they lie as pigment powder and are easily smudged. Unfortunately, pastel colours lose their luminosity and tonality if fixed with a varnish and so are best preserved in deep mounts behind glass. Edgar Degas often overcame the fragile nature of true pastel painting by the unorthodox method of working on turpentine-soaked paper, which absorbed the powdery pigment.
Cassatt, Mary: Mother Combing Sara's Hair (No. 1)Mother Combing Sara's Hair (No. 1), pastel on paper by Mary Cassatt, 1901.Bridgeman/Art Resource, New York
Eighteenth-century portrait pastellists, such as Maurice-Quentin de La Tour, Jean-Baptiste Peronneau, Jean-Étienne Liotard, Rosalba Carriera, and Anton Raphael Mengs, blended the pigment with coiled paper stumps so the surface resembled that of a smooth oil painting. Later pastel painters, such as Degas, Henri de Toulouse-Lautrec, Mary Cassatt, Everett Shinn, Odilon Redon, and Arthur Dove, contrasted broad masses of granular colour, spread with the side of the stick, with broken contours and passages of loose cross-hatching and smudging. They often used the tinted ground as a halftone, and, according to the amount of manual pressure exerted on the chalk, they varied the degree of pigment opacity to extract a wide range of tints and shades from each pastel colour.
Carriera, Rosalba: Young Lady of the Leblond FamilyYoung Lady of the Leblond Family, pastel drawing by Rosalba Carriera, 1730; in the Accademia, Venice.SCALA—Art Resource/Encyclopædia Britannica, Inc.
Oil pastels
Oil pastels are pigments ground in mastic with a variety of oils and waxes. They are used in a similar way to that of French pastels but are already fixed and harder, producing a permanent, waxy finish. Oil-pastel paintings are generally executed on white paper, card, or canvas. The colours can be blended if the surface of the support is dampened with turpentine or if they are overworked with turpentine. They are popular for small preparatory studies for paintings. Glass paintings
Glass paintings are executed with oil and hard resin or with watercolour and gum on glass sheets. These have been a folk art tradition in Europe and North America and, from the 15th to the 18th century, were regarded as a fine art in northern Europe, where they have been more recently revived by such painters as Willi Dirx, Ida Kerkovius, Lily Hildebrandt, Klee, Oskar Schlemmer, and Heinrich Campendonck. Colours are applied from the back in reverse order. Unpainted areas of glass are often coated with mercury, providing a mirror background to the coloured images. That treatment creates the kind of illusionary, bizarre spatial relationship between the viewer and picture space sought by Italian artist Michelangelo Pistoletto with his use of photographic images fixed to a polished steel sheet. The colours seen through glass appear translucent, jewel-like, and, since they cannot be touched, even magical. Ivory painting
Ivory painting was practiced in the 18th and 19th centuries in Europe and America for portrait miniatures. These were generally oval-shaped and designed as keepsakes, lockets, and mantle pictures. They were painted under a magnifying glass in fairly dry watercolour or tempera stippling, with sable- or marten-hair brushes on thin, semitranslucent ivory pieces. Corrections were made with a needle. The velvet quality of their colours was enhanced, on the thinner ivories, by the glow produced by a gold leaf or tinted backing. Lacquer
Lacquer has been a traditional Chinese medium for more than 2,000 years. It combines painting with intaglio relief. Linen-covered wood panels are coated with chalk or clay, followed by many thin layers of black or red lacquer tree resin. The surface is polished and a design engraved, which is then coloured and gilded or inset with mother-of-pearl. Layers of compressed paper or molded papier-mâché have also provided supports. In China and Japan, lacquer has been used principally for decorating shrine panels, screens, caskets, panniers (large baskets), and musical instruments.
Tokugawa-period writing box of black lacquered wood decorated in gold paint, inlaid lead, and pewter, attributed to Ogata Kōrin (1658–1716).Courtesy of the Seattle Art Museum, Washington
Sand, or dry, painting
Sand, or dry, painting is a traditional religious art of the North American Indians; it is still practiced in healing ceremonies among the Navajos of New Mexico and Arizona. Ground sandstone, natural ochres, mineral earths, and powdered charcoal are sprinkled onto a pattern marked into an area covered with yellow-white sand. The patient sits in the centre of this vivid symbolic design of coloured figurative and geometrical shapes. Following the ritual, the painting is destroyed. These “floor” pictures influenced Pollock in his horizontally spread action paintings. Paper