Color Pigments in Painting

Since ancient times, only colors found in nature were used in painting, either in the form of colored clays (ochres) or in the form of minerals (malachite, azurite, auripigment, lapis lazuli, limestone, light spar, etc.). Pigments were obtained from these materials by crushing, sieving, decanting. Some of these natural pigments, being too expensive or not very resistant, were gradually replaced by synthetic pigments.

Organic dyes have completely different properties, being substances soluble in water, alcohol and oils, unlike mineral dyes which are insoluble, being solid substances of a certain color with constant physical and optical properties.

White pigments:

white pigments

• Lead white (Lead pencil) Its main feature is that it has a great covering power and dries quickly when mixed with oil. In painting, this type of white is irreplaceable in the preparation of oil primers and in painting in several layers. However, it is very toxic, serious poisonings, even fatal, are known with this color. It cannot be used for fresco and tempera because it is unstable in alkaline environments. It turns yellow in the dark if mixed with linseed oil, but recovers in the light.
• Zinc white or zinc oxide , is a light powder, has a dazzling white color, with a slightly bluish tint. It is stable to light. Zinc white is suitable for tempera, watercolor , gouache and pastel techniques. It is not recommended for oil painting because it absorbs a lot of oil, dries slowly, has poor covering power and causes the color layer to crack.
• Titanium white or titanium dioxide . Of all the pigments, this is the one with the highest covering power, it is non-toxic, insensitive to the action of atmospheric agents.

Ochre pigments:

Ochre pigments

• Ochres are obtained from iron hydroxides with kaolin, silicates, gypsum stone and organic substances. This earth color has different shades of yellow: Satin ocher comes from Vaucliuse (France), siennas come from Tuscany and Sicily (Italy). Ochres are resistant to atmospheric agents, light, have a great covering power. They can be used in any painting technique, including mural.
• Natural sienna is a dark, transparent ochre, most prized if it has a cool, deep greenish hue. It transforms upon firing into a burnt sienna with a reddish-brown tone. In the history of European painting, siennas and ochres have been encountered since ancient times.
• The shade is a mixture of limonite, manganese hydroxide, clay and silicates. Stable to air and light, it has a high covering power and is non-toxic. When calcined, it acquires a warm reddish tone and passes into burnt shade . Both varieties of shade are stable in alkaline environments, so they can be used in weak tempera painting, watercolors, gouache and pastel. In oil painting, it darkens the colors with which it is overlapped, has a tendency to crack, but dries quickly.

Yellow and orange pigments:

Yellow pigments

• Cadmium yellow has intermediate light tones from yellow to orange. It is stable to light and air, has good covering power. It can be used in all painting techniques.
• Citron yellow has a color that ranges from lemon yellow to a greenish tinge. It is usually recommended for oil and watercolor painting. It is unstable to light and partially soluble in water.
• Cobalt yellow has a pure hue, but poor covering power, is stable to light, and is more suitable for watercolor than oil. Because it is expensive, it was little used.
• Naples Yellow . The quality of this pigment depends on the manufacturing process. It has a pale hue and turns black when exposed to hydrogen sulfide.
• Chrome yellow has beautiful saturated tones, has high covering power, but is unstable to light, fades easily. Can be used for fresco and tempera.
• Indian Yellow . Unadulterated yellow is a product of pathological metabolism in cows that eat mango leaves. It is a pigment of a beautiful golden-yellow, even orange hue, but applied in a thick layer becomes yellow-brown. It is light-resistant.

Red pigments:

Red pigments

• Natural red clays actually contain crushed iron ore – hematite or chalcocite, which contains iron oxide with the addition of alumino-silicates. They are stable to air and light, have a high covering power, and the color intensity can be increased by firing.
• Venetian red and English red . These pigments have approximately the same tonality and have great covering power.
• India red has a light purple hue, it is almost pure iron oxide. This pigment has the highest covering power known to date, and considerable intensity.
• Carmine varnish is a natural dye obtained from parasitic insects of the cactus Cocus cacti. It is not stable to light. It is more stable in oil than in watercolor.

Blue pigments:

Blue pigments

• Cobalt or cobalt aluminate is very stable to light, air and mixing with other colors. It has an intense hue and can be used in all painting techniques, including mural painting.
• Cerulean or cobalt stannate – is a light blue with a greenish tint, it is perfectly stable to light and in mixtures with other pigments. It has a higher covering power than cobalt.
• Dark violet cobalt is a light-stable color and when mixed with other colors, can be used in fresco.
• Ultramarine is a complex compound containing sodium silicate, aluminum silicate and sulfur. There are different varieties : blue ultramarine , with a violet hue, green , purple , and yellow and red ultramarine are not suitable for painting. In order to be used in painting, sulfur must be removed from the composition of ultramarine. It is stable to light and air, but very sensitive to acids . Natural ultramarine or lapis lazuli – is a blue semiprecious stone, stable to light and air, but also sensitive to acids.
• Indigo - natural dye obtained from the Indigofera tinctoria plant, which grows in India. It has a blue-violet hue, with a bronze sheen. It is stable in indirect light, but fades in the sun. It is indicated in water painting techniques.

Green pigments:

Green pigments

• Green clays – from Verona and Bohemia . They are washed earths with properties similar to those of ochres. They are complex combinations of minerals. They are perfectly stable to air and light and can be used in any painting technique.
• Chromium green, or anhydrous chromium oxide , is perfectly stable to light and air and is used in all painting techniques.
• Emerald green is also very stable in mixtures and in all techniques, but has a cooler and deeper color than chrome green.
• Cobalt green is also a stable pigment in all painting techniques, but has a diminished covering power.
• Spanish green or basic copper acetate . It is a pigment that has a vinegary odor. Because it is unstable in mixtures, it disappeared from the palette of painters in the 19th century.

Brown pigments:

• Van Dyck Brown is a mixture of black pigments, dark mulberry lake and charcoal.

Van Dyck Brown Pigments

• Asphalt or bitumen – dissolved in oil when hot allows for beautiful browns for glazes. It prevents normal drying and cracks, so it is not recommended for oil painting.
• Sepia is a dark brown color, obtained from the coloring substance secreted by the mollusk Sepia Officinalis, it is unstable to light. It is most commonly used in watercolor.

Black pigments:

• Ivory black is obtained from the anaerobic combustion of ivory pieces.

Ivory black

• Bone black is obtained by carbonizing various bones. It dries slowly and is very absorbent.
• Lamp smoke black obtained by burning carbon substances. It is not recommended in oil painting because it migrates into the layers of color, dries slowly. It is used in the manufacture of inks and brushstrokes, but also in watercolor colors.
• Black iron oxide – is a very stable pigment, mixes well with oil. It is better than ivory black
• Cobalt black or cobalt peroxide – it is a perfectly stable intense black, it can be used both in fresco.