Pigment History page 4

On February 4, 1828, the prize was awarded to Jean Baptiste Guimet who submitted a process he had secretly developed in 1826. Guimet’s ultramarine was sold for four hundred francs per pound. In Paris a short while later, lapis lazuli cost between three to five thousand francs per pound at that time. Independent of Guimet, Christian Gottlob Gmelin, a professor of chemistry at the University of Tubingen discovered a slightly different method based on the analytical results of Désormes and Clément which he published only one month after Guimet. Gmelin claimed that he beat Guimet and a rivalry ensued for years but France upheld Guimet’s right to the prize. By about 1830, Guimet’s ultramarine was being produced at a factory that he opened in Fleurieu-sur-Sâone, France. F. A. Köttig at the Meissen porcelain works in Germany was producing Gmelin’s method by 1830 as well (Plesters 1966, 76).Artificial ultramarine, also known as French ultramarine is Na8-10A16Si6024S2-4. It was made by heating, in a closed-fire clay furnace, a finely ground mixture of China clay, soda ash, coal or wood, charcoal, silica and sulfur. The mixture was maintained at red heat for one hour and then allowed to cool. It was then washed to remove excess sodium sulfate, dried and ground until the proper degree of fineness was obtained (Harley 1970, 55). It could be ground to larger particles to obtain a deeper color or finer for a pigment with better tinting strength. This process, known as the indirect process, was also used to produce a green color (Plester 1966, 77). Heating the blue pigment with sal ammoniac or any hydrochloric acid, respectively (Gettens and Stout 1966, 167) made violet and red varieties that were developed in Germany between 1870 and 1880. The red and violet varieties, however, had poor tinting strength (Plesters 1966, 76).French ultramarine blue was non-toxic and as permanent as the natural variety but darker and less azure. It was prepared in both oil and watercolor. In oil it dried well despite a high percentage of oil needed for grinding and in watercolor produced clean washes (Field 1885, 145).The artificial variety is distinguished microscopically from the natural by its more rounded finer particles (Field 1885, 164). They react the same chemically by being bleached in acetic acid (Laurie 1914, 55).Madder red was another important synthetic pigment produced in the early years of the nineteenth century. This time, cost was not a factor in its development, but the need for a more permanent version of its ancient precursor. Dyes derived from the extract of the madder plant’s root (rubia) were in use by the ancient Egyptians for coloring textiles (Plesters 1966, 28). Bleached areas of natural madder can frequently be seen on fifteenth and sixteenth century paintings (Wehlte 1982, 92).In the early nineteenth century, the natural madder dyestuff was developed as a pigment. Later in the century, a synthetic version was produced. In the mid-eighteenth century, most natural madder (Rubia tinctorum) was grown in Holland. England was importing all of the madder used in their textile production from Holland at a cost of three hundred thousand pounds per year (Laurie 1966, 28).In 1804, the Societé d’Encouragement des Artes awarded a medal to Sir Henry Englefield of England for a method of the preparation of madder lakes, dyestuffs that are attached to an inert substrate. This is a necessary process in order to grind such a pigment in oil. George Field had developed a press for extracting the dye that would filter and powder it. In an 1806 notebook, he noted his anger upon learning about the award because he had already been producing madder lake. He recorded his madder lake preparation in a notebook dated November 1808. One-half pound of alum (the inert substrate) was added to one-half pint of hot water and heated. He then added three-quarters of a pound of washed madder and heated the mixture for almost one hour. He strained the mixture, dried it on heat and let it set until it crystallized. He noted that it was “beautifully purple” (Richter and Härlin 1974, 81).The madder lakes, which were prepared in a variety of shades from brownish to purplish to bluish reds were known to have superior permanence than the unlaked madders. It was a good glazing color that spread well in oil and was also prepared as a watercolor (Richter and Härlin 1974, 80).In 1826, the French chemists Colin and Robiquet first isolated the coloring principle from the madder plant and published their findings in Annales de Chimie XXXIV, “Recherches sur la matière colorante de la garance” in 1827. In the madder root, there are two coloring agents. One is the permanent alizarin and the other rapidly fading purpurin. It was the alizarin component (C14H804) that was made synthetically by the German chemists C. Graebe and C. Lieberman in 1868 and patented in England the same year (Gettens and Stout 1966, 91). The synthesis caused the rapid decline and almost total disappearance of the madder-growing industry. As in the natural madder lake aluminum hydrate (alum) is used as a substrate for the synthetic variety, most commonly known as alizarin crimson.Although alizarin crimson had superior permanence over the madder lake because of the absence of purpurin, both madder lakes were used in oil and watercolor painting. Some painters complained that the synthetic variety was less saturated and brilliant than madder (Gettens and Stout 1966, 91). Both varieties were non-toxic, slow drying in oil and the deeper shades were more lightfast than the lighter ones. Both were compatible with all other pigments (Wehlte 1982, 111-112).The base on which both varieties are substrated is indistinguishable under the microscope. Nor can the natural and artificial be identified even at high magnification. They are both soluble in hydrochloric acid (Gettens and Stout 1966, 91).Crimson, a natural dyestuff made from the bodies of the insect, cochineal was also prepared on a lake base. Although known since at least the sixteenth century, Crimson lake was a more permanent version developed in the nineteenth century.William Henry Perkin (1838-1907), while a student at the Royal College of Chemistry in England, founded the organic color industry of coal tar dyes. He was researching the synthesis of quinine when he accidentally came upon an extract of purplish hue when oxidizing impure aniline with potassium bichromate (Pavey 1984, 39). The term aniline dyes are applied to all chemicals derived from the distillation of coal tars. Coal tar, a by-product of coke and gas manufacturing, is a compound consisting mainly of carbon, hydrogen, nitrogen and sometimes sulfur (C27H25N4 (SO4) ½).Since Perkin’s discovery, many thousands of coal tar dyes have been prepared. Some are used in the preparation of lake pigments such as crimson. They were hastily introduced into painting because of their richness and brilliance but serious damage resulted as many of them are quite fugitive (Gettens and Stout 1966, 108). Mauve, a reddish violet, was one of the first coal tar pigments which was prepared as a lake by substration on clay, tannin and mineral colors. It required a large proportion of filler to gain any body. Since coal tar pigments tended to be transparent, they were mainly employed in watercolor (Doerner 1934, 90). In the second half of the nineteenth century, a standard for the permanence of artists’ pigments was established that required coal tar colors to be at least as permanent as alizarin madder lake (Gettens and Stout 1966, 108).Magenta, a brilliant, red-purple aniline dye was produced in 1858 by Natanson. It was named after the site of a battle in Italy that took place the same year (Pavey 1984, 39).C. Himly of Kiel invented antimony vermilion or orange antimony sulfide in 1842. The high cost of cadmiums and vermilions may have prompted its manufacture from antimony sulfide (Sb2S3). Antimony vermilion ranged in hue from orange to deep red. Its use was known in the adulteration of real mercury vermilion, but it was rarely employed by artists due to its fugitive nature. Its main application was as a pigment in the rubber industry (Gettens and Stout 1966, 94). Murdock Scotland patented it in 1847 (Mayer 1970, 40).The high cost of cobalt violet prompted the development of the permanent pigment manganese violet. Manganese ammonium phosphate ( (NH4) Mn2 (P207)2) was first prepared by E. Leykauf in Nurnberg in 1868 by melting together manganese dioxide and ammonium phosphate. The resulting violet mass was added to phosphoric acid and heated until the correct color was obtained. Although it was a truer violet hue than cobalt violet, dark (which is redder and brighter) it was not used very much by artists because of its dull tone and poor hiding power (Doerner 1934, 81).The nineteenth century painter had no real gap in his palette with regard to browns, blacks and earth colors. Pigments such as the umbers and siennas were in use since antiquity and their stability (with few exceptions) was well known. However, by the nineteenth century, cracks had developed in the paintings of the seventeenth and eighteenth centuries where bitumen (also known as asphaltum) was used as an underpainting color. Rembrandt and other seventeenth century painters as a final glaze color also used it and its cracking was evident (Wehlte 1982, 119). One of the more popular browns developed in the nineteenth century was Egyptian Mummy. Although it is unknown who first thought of grinding it into a fine powder and, without disguising its name, using it as a pigment; it was known as an internally taken drug in sixteenth and seventeenth century Europe. It was not uncommon for a drug to be tried out as a pigment and its introduction into the artists’ palette is believed to be in the early nineteenth century (Harley 1970, 142).The raw material came from the large communal tombs near the Pyramids in Egypt. The ancient Egyptians used large quantities of liquid asphaltum to embalm the bodies of humans as well as sacred animals along with aromatic herbs and resins. Asphaltum is a complex natural mixture of hydrocarbons that are the residue of the natural evaporation of petroleum. When the bodies were excavated, they were found to be wrapped in bandages that were somewhat decayed. When Wehlte visited von Moeve’s color factory in Berlin, he obtained a sample of the raw material for the pigment that contained decayed bandages, thick arteries and hollow bones (Wehlte 1982, 120).The first known recipe for the preparation of Egyptian Mummy as a pigment was in 1797. It was anonymously listed in A Compendium of Colours, and other Materials used in the Arts dependent on Design, published in London. The instructions for its preparation were:The finest brown used by Mr. West [presumably the American painter, Benjamin West] in glazing is the flesh of mummy, the most fleshy are the best parts; … it must be ground up with nut oil very fine, and may be mixed for glazing with ultramarine, lake, blue, or any other glazing colours; when it is used, a little drying oil must be mixed with the varnish, without which it will be longer in drying, which is the only defect it has, as it may be used in any part of a picture without fear of changing (Harley 1970, 142-143).Until 1925, genuine Mummy was a common shade listed in the range of artists’ colors.Sepia has been known since classical times as writing ink. It was available in stick form from which artists could prepare liquid ink with gum arabic. Its method of preparation was improved in the late eighteenth century and was prepared as a watercolor and oil pigment.The exact chemical composition of sepia is unknown but it is a complex nitrogenous organic compound with a characteristically fishy odor (Gettens and Stout 1966, 155). It is derived from the secretion and glands of the cuttlefish (sepia officinalis), mainly found in the Adriatic Sea. When the cuttlefish is threatened or attacked, it releases a dark brown liquid as a disguise. Suspending them in the air-dried the ink bags (glands). Andrew Ure, writing in London in 1843 (A Dictionary of Arts, Manufacturers and Mines, p.1098) added that the ink sac must be removed and dried as soon as possible after the fish was caught because it putrefied quickly (Harley 1970, 145).Due to the pale nature of the dye, Professor Seydelmann (1750-1829) of Dresden developed a method of achieving a more concentrated variety in the 1770s by extracting the dye with potassium hydroxide (Wehlte 1982, 118). The dried extract was first ground alone and then ground and boiled with an alkaline lye solution. It was then filtered and neutralized with hydrochloric acid. The resultant brown coloring matter was separated, washed in water and dried at a low temperature. The very fine grain powder was ground with gum arabic and made into cakes or prepared in tubes for watercolor (Harley 1970, 145).A sepia cake from the colorman Rudolph Ackerman was found at a pharmacy near Darmstadt, Germany. It was stamped, as was the practice of colormen at the time, with ” ’Printseller and colourman’ Rudolph Ackerman.” His watercolors were well known and references to them can be found in many nineteenth century books on painting. In 1801, he published A Treatise on Ackerman’s Superfine Water Colours in London (Richter and Härlin 1974, 80). Sepia was also produced in Italy and known as Roman Sepia.

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