ALIZARIN

(Also known as Alizarin Crimson in modern pigments). Same as Madder, except that it was made from the European Madder root. Since the 1850s (approximately) it has been made synthetically with an identical chemical composition to Madder but with a superior clear tone and lightfastness. By manipulating these chemicals, a range of shades has been made from Scarlet to Ruby. All alizarin lake colors (see crimson lake) are permanent to light and to the gaseous atmospheres of urban areas. However, when mixed with Ochre, Sienna and Umber, they lose their permanence. and when mixed with blacks or oxides, its permanence is not affected at all. Excellant as a glazing color over a dry surface. According to Maximillian Toch, " the medium shade of Madder Lake shows no light action after one year to the sun under glass". Purple madder, is a different pigment altogether, in that it is permanent to diffused indoor light, but not to ultra-violet light, and should therefore never be exposed to sunlight.

ALUMINA HYDRATE

When ground in a low acid linseed oil, this pigment is as transparent as glass, and has the least hiding power of any pigments. It therefore reduces the opacity of all other pigments, and becomes inert when mixed with them. It does however add to the yellowing of pigments over time, as it takes an enormous quantity of oil to reduce it to a paste. Therefore, this pigment is extremely valuable when used for glazing techniques, and traditionally, with a more golden/yellow array of colors to mask the yellowing quality. This can also be used to advantage when creating a glaze meant to yellow a painting for the purpose of imparting age to it.

ANTWERP BLUE

Usually a Prussian Blue containing 25% or more of Alumina Hydrate, making it a translucent blue. When mixed with Titanium or Zinc oxides, it makes a sky-blue which a permanent to light. As a glazing medium, when mixed wtih Burnt Sienna, it creates a translucent dark maroon. According to Maximillian Toch, Blakelock used Antwerp Blue and Burnt Sienna for his dark glazes. It is however a fairly useless pigment as Chinese or Prussian Blue give the same, but stronger results.

ARTIFICIAL BARIUM SULPHATE

In France this pigment is known as Blanc Fixe, meaning permanent white. It has even less covering power than zinc white, which makes it a very translucent pigment, best used as an extender or as a glazing medium.

ASBESTINE

A course shredded material which is used in pigments to prevent settling or hardening.

ASPHALTUM

(Bitumen). It's very tempting to use asphaltum in underpainting as it allows for a sketchy brushstroke, not unlike that which is possible with graphite. It is a complete disaster in traditional uses, and can be extremely damaging as an underpaint to the more stable pigments painted upon it. However, the strange, rough quality of the material is quite interesting for more contemporary uses, and is worth experimenting with. It is however a poor dryer, Pulverized asphalt is heated in hot oil as a part of its preparation, therefore it is obviously soluble in oils, but historically boiled linseed oil would be added to improve its drying abilities. It also has a tendency to soften in higher temperatures, adding to its instability as a traditional pigment. This opens it up to experimentation in contemporary uses; it has a tendency to soften in higher temperatures, causing deep cracks in the top layers of paint, the asphaltum thus pressing through. Rembrandt used it for a glaze, where it caused no damage at all, thus opening it up to uses over other treatments/pigments. It requires 150% oil, making it an exceedingly fat paint, and is traditionally advised against for every traditional technique including fresco. Consider the modern use of /asphalt: there may be possiblities available in many of the paving/industrial materials used which are not "painting" materials. Remember during all experimentation however, that the stability of the material over time might be limited, and use this toward the advantage of the work, rather than the disadvantage.

AUREOLIN

A nitrite of cobalt and potassium, which makes a tranparent yellow color which is permanent to light. When used with sufficient oil or coated with varnish, it has the added quality of being unaffected by gaseous atmosphere, as well. It is used best as a glazing color as it has poor coverage, and yet is fairly useless as the lighter cadmium yellows give the same results.

AZURE BLUE

According to history, this name would mean "blue blue". However, in manufactured pigments it is a tone similar to Cerulean blue, and is usually a mixture of Prussian or Ultramarine blue with Zinc white. It is permanent to both light and air.

AZURITE & BLUE VERDITER

Also mountain blue, lapis armenius, azurium citramarinum (as opposed to azurium ultrmarinum), and in Pliny's time called "Armenian stone" when Armenia and Spain were the chief sources of supply. Latin borrowed a Persian word for blue, lajoard, which in the form of lazurium became azurium, and gave us our word azure. (This word probably meant the Persian mineral, lapis lazuli, but it came to mean the color blue in general.) It is composed of basic carbonite of copper, found in many parts of the world in the upper oxidized portions of copper ore deposits (also refer to blue copper pigments to cross reference). Azurite mineral is usually associated in nature with malachite, the green basic carbonate of copper that is far more abundant. According to Lucas (1962), azurite may have been employed as a paint pigment as early as the fourth dynasty in Egypt, but was not widely used then nor in the classical world because of the synthetic copper pigment, Egyptian blue (usually all synthetics were less expensive and more abundant). Azurite was the most important blue pigment in European painting throughout the middle ages and Renaissance by contrast, despite the more exotic and costly ultramarine having received greater acclaim. Azurite was commonly used as an underpaint to ultramarine as well. It was also the most important blue pigment in the paintings of the far east, used widely in the wall paintings of the Sung and Ming dynasties in China. It was also used in Japan, especially on paintings of the Ukiyo-e school, and is still used today. To a limited extent it was used by the pre-Columbian Indians of the American Southwest and later in Spanish mission church paintings.

The invention of Prussian blue at the beginning of the eighteenth century displaced azurite from the European palette. Hungary was the principle source of Azurite in Europe until the mid-seventeenth century when the country was overthrown by Turks and supplies were cut off. This is substantiated by the fact that Hungary is a present day locality for Azurite. Other sources may have been Chessy near Lyon in France, and Sardinia, both of which remain so. There may have been others unreported to which the Germans had access, as they capitalized on the export. Azurite sometimes looks a little like lapis lazuli, and the two were often confused in the middle ages. To tell them apart with certainty the stones were heated red-hot. Azurite turns black when this is done, and true lapis is not injured. To prepare a color from it, lump azurite is ground into a powder, and sieved. Coarsely ground azurite produces dark blue, and fine grinding produces a lighter tone; however if not ground fine enough, it is too sandy and gritty to be used as a pigment. The medieval system included washing it to remove any mud and then separating the different grains by some process of levigation. If plain water is used it is a slow, laborious process, so they used solutions of soap, gum and lye. The Japanese produce three grades: coarse, medium and fine, thus all three have different tones to them. A fourteenth century text tells us that "There are some confounded tricksters who put sand into blue deliberately to increase the weight (for sales) and it is the ruin and destruction of the color." Merchants would also put all the best blue at the top of the bag, and the poorer quality at the bottom. When azurite is washed, the very fine particles are rather pale, greenish sky-blue, and not much admired for painting. Its fineness was suitable to the pen, and was chiefly used for the purpose of putting pen flourishes of blue around large letters (usually in red) in books. There was another blue still better for this purpose; turnsole, often used in conjunction with fine azurite, and the palest qualities of azurites seem not to have been in any great demand. To some extent they were used for modeling up the darker qualities in painting, so as to produce an effect in several values of blue without having to dilute the dark blues with white. Dark azurite blues in tempera on walls could be modeled up simply by roughening the surface with a stick of wood. Scratches on the dark blue looked light, but this was not very long lasting. The best grades of azurite for painting were coarse: not sandy, but so course that is was quite laborious to lay them on, especially in egg tempera.

For this reason size was often used as a binder to hold them firmly in place. (Size is more easily affected by protracted dampness or by washing than egg tempera, and blues in wall paintings have therefore sometimes perished through the destruction of their binder where colors in tempera have stood.) It was necessary to apply several coats of azurite to produce a solid blue, but the result was quite beautiful. The actual thickness of the crust of blue added to the richness of the effect, and each tiny grain of the powdered crystalline mineral sparkled like a minute sapphire, especially before it was varnished. The open texture of a coat of azurite blue has often been its undoing on panels; the varnish sinks into it and surrounds the particles of blue. As the varnish yellows and darkens, the power of the azurite to reflect blue light is destroyed : strangled by the varnish. Though skilled restorers can remove surface varnishes perfectly, no means has been devised of removing that which has penetrated into the body of a film of azurite. A large number of blacks in medieval paintings were originally blues, and often is still blue at heart, only obscured by the discoloration of the varnish. Azurite was requested in medieval contracts for important paintings, unless the still more precious ultramarine was to be used. It was not as choice or expensive as ultramarine, but it was the best blue of the panel and wall painter for all ordinary purposes, and widely used in manuscripts as well. Its texture and surface quality was highly watered through the Middle ages, however in oil painting this surface quality is lost, and the pigment went out of use as the oil medium became popular. Though it has a reputation nowadays to turn black, it is incredibly permanent. It does not blacken from the effects of sulphur gases as some chemists have supposed, but from the action of the strong alkalis improperly used in picture cleaning, and from the purely optical effect of darkened varnish surrounding its particles. QUICKNOTES: If too finely ground it turns white; best mixed with sizing or water based binders as it turns black in oil; permanent but varnishes can destroy it; best as an underpaint, familiarly under ultramarine.