Colour and art: A brief history of pigments

ARTICLE IN PRESS Optics & Laser Technology 38 (2006) 445–453 www.elsevier.com/locate/optlastec Colour and art: A brief history of pigments J.R. Barnetta,, Sarah Millerb, Emma Pearceb a School of Plant Sciences, The University of Reading, PO Box 221, Reading RG6 6AS, UK b Winsor & Newton, Whitefriars Avenue, Harrow Middlesex HA3 5RH, UK Available online 21 July 2005 Abstract Human beings have had an inherent urge to leave their mark in the form of works of art since prehistoric times. This has driven the quest for new and better pigments with which to make paints. This paper describes the origins and composition of earliest earth pigments used by primitive man to decorate the walls of caves through to the synthetic pigments developed in more recent times. Despite modern technology, the artist’s palette remains a mixture of the pigments used by cave artists, natural pigments used in the middle ages, and modern organic compounds. r 2005 Elsevier Ltd. All rights reserved. Keywords: Pigments; Art history; Artists’ colours; Painting 1. Introduction From prehistoric times humans have left their mark on their environment in the form of painted images, whether in the form of simple handprints, works of fine art or spray-can graffiti. It seems that people have an underlying conscious or subconscious urge to mark their passing. It may be that primitive man made marks by scratching trees or rocks with stones as a way of marking a track, indicating a source of food or water or even marking territory. At some stage, however it was discovered that some materials worked more effectively when mixed with a medium such as water or saliva, and painting was born. The prehistoric paintings that have survived tend to be located in caves, under overhanging rock ledges, or in places where the climate was such that they were not washed or weathered away. Archaeologists and historians like to offer mystical interpretations of the meaning and functions of these paintings, but it is likely that many were made simply to pass the time. It is easy to imagine people sheltering from heavy rain or hot sun Corresponding author. E-mail address: [email protected] (J.R. Barnett). 0030-3992/$ - see front matter r 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.optlastec.2005.06.005 under an overhanging ledge at the foot of a rock face and making the pictures as a way of occupying themselves while they waited for conditions to improve. Once it had been discovered that pigments could be used to colour a surface, the practice of body painting began and persists to this day. Painting the body could be used to indicate status or to lend a sense of mystery to a superstitious practice. The Europeans who first encountered the native peoples of North America called them Red Indians because of their practice of painting their bodies with red ochre. This has been described ‘‘as a shield against evilya protection against the cold in winter and insects in summer’’ [1]. There can also be little doubt it made warriors appear more fearsome. It would almost certainly boost the confidence of the warrior in his own abilities in the same way as a military uniform in modern times. The same purpose was served by woad, the pigment applied by ancient British races. In this case it may well have been felt that applying this pigment to the body gave the warrior magical powers, since woad is an antiseptic and was known to have the power of preventing wounds received in battle from becoming septic. Interestingly, the woad plant Isatis tinctoria is currently under investigation for its antiinflammatory properties [2]. ARTICLE IN PRESS 446 J.R. Barnett et al. / Optics & Laser Technology 38 (2006) 445–453 2. The first paints As might be expected, prehistoric painters used the pigments available in the vicinity of their homes. These were the so-called earth pigments, soot from burning animal fat and charcoal from the fire. The colours were yellow ochre, red ochre, and black. Water was the binding agent and enabled the pigment to be sprayed from the mouth or painted onto the surface using the fingers as brushes. Fig. 1 shows bison painted on a cave wall in Altamira, Spain and Fig. 2 the stencil of a hand from Avignon in France; an early example of ‘‘Kilroy was here’’. These paintings are more than 30,000 years old while geometrical designs in the Blombos Cave in South Africa were painted about 70,000 years ago [3]. The word ‘‘ochre’’ comes from the Greek word Ochros, meaning yellow, so the name yellow ochre is tautologous. The chemical responsible for the colour is ferric oxide monohydrate Fe2O3
H2O, familiar to everyone as rust, and it is found mixed with silica and clay. Grinding and washing produces the pigment, which is essentially yellow clay. Red ochre is produced by heating the yellow ochre to drive off the water and produce anhydrous ferric oxide. By controlling the Fig. 2. Hand stencil from the cave at Avignon, France. heating it is possible to produce a range of warm yellows to bright red. Red ochre occurs naturally in volcanic regions where thermal activity has caused the dehydration [4]. The colour has excellent permanence and the abundance of raw material means that ochres remain among the cheapest artists’ colours available. The palette of these early people was limited to those materials readily to hand and requiring only the most basic technology for their preparation. Large parts of the spectrum of colours, notably blues and greens, were not available to them, yet they produced strikingly vivid images through skilful use of what they had. 3. The Egyptians Fig. 1. Paintings of bison in the Altamira Caves, Spain. The Egyptians began serious colour manufacture from about 4000 BC. They introduced washing of pigments to increase their strength and purity. They also introduced new materials, the most famous of which was Egyptian blue—first produced around 3000 BC. This is a very stable pigment and still appears as if fresh on wall paintings produced at that time. The pigment is calcium copper silicate (CaCuSi4O10) made by mixing a calcium salt (carbonate, sulphate or hydroxide), a copper compound (oxide or malachite) and sand (silica). This was heated to produce a coloured glass or frit and ground to a powder for use. Paints were made by using the ground pigment with gums or animal glue, which made them workable and fixed them to the surface being decorated. The Egyptians also used malachite (Fig. 3), probably the oldest known green pigment, and azurite, a greenishblue pigment. They are chemically similar, comprising basic copper carbonate (2CuCO3
Cu(OH)2), and occur ARTICLE IN PRESS J.R. Barnett et al. / Optics & Laser Technology 38 (2006) 445–453 447 4. The Chinese, Greeks and Romans Fig. 3. Malachite stone. as natural minerals which the Egyptians converted to pigment by crushing and washing. Both appear in Egyptian tomb paintings from the fourth dynasty and in European paintings from the 15th and 16th centuries. Egyptian women also used malachite to paint their eyelids. Orpiment, yellow sulphide of arsenic was used for bright yellow or gold, and realgar or red sulphide of arsenic for bright reds [5]. These pigments were used as long ago as the 16th century BC and continued in use until the 19th century. Arsenic sulphide (As2S3) is found in volcanic and geothermal regions, although it is also found with limestone and dolomite. The colours are not permanent and fade on exposure to light. Jarosite, potassium ferric sulphate hydroxide KFe3(SO4)2(OH)6, was used to produce a pale yellow. Jarosite is named after the Jaroso Ravine in Sierra Almagrera, Spain, where it is found, and it is formed as a result of weathering of volcanic rocks. Its presence on the planet Mars has recently been invoked as evidence for water limited chemical weathering of the surface [6]. Vegetable dyes were also developed and the Egyptians were the first to ‘‘fix’’ dyes onto a transparent white powder base to produce pigments. This is the process known as lake making. Solutions of organic dyes extracted from parts of plants were mixed with hydrated clay or tannin to form an insoluble pigment. The old masters used chalk or alum for this purpose [4]. Chinese science and technology was highly developed long before western civilisations appeared. The Chinese developed vermilion around 2000 years before the Romans used it. Vermilion, a red pigment, is made by crushing, washing and heating the mineral cinnabar, or mercuric sulphide (Fig. 4) to give a strong red pigment. Alternatively it was made by mixing mercury with molten sulphur and heating the mixture to produce the compound. The Greeks’ contribution to painting was the manufacture of white lead pigment which remained the most used white pigment available to artists until the 19th century. It is still regarded as the whitest of the white pigments, consists of basic lead carbonate (2Pb(CO3)2
Pb(OH)2) and is, of course, toxic. Like cinnabar, it was used as a cosmetic by Greco-Roman ladies, who used it as face powder with predictable effects on their health and that of the men who kissed them. It continued in use as a cosmetic into the middle ages and beyond in Europe. White lead was made by stacking lead strips in porous jars with vinegar and burying the jars in animal manure, which generated the heat necessary to speed up the reaction (Fig. 5). With a few refinements, this process continued to be used until the 1960s. The physical structure of white lead and its reaction with the oil give a very flexible, quick drying and permanent paint film, particularly important in oil painting. The Greeks also developed the use of red lead, which was used for priming metal in construction until it was banned in the 1990s. Red lead is a form of lead oxide (Pb3O4) and is found as the mineral minium after the River Minius in northwest Spain. It is also manufactured by heating litharge (PbO) in air (Fig. 6). The Romans made use of the pigments developed by the Egyptians and Greeks. One of the most important Fig. 4. Cinnabar. ARTICLE IN PRESS 448 J.R. Barnett et al. / Optics & Laser Technology 38 (2006) 445–453 harvested. Since about 12,000 molluscs produced only about 1.4 g of the pigment, it was very expensive and affordable only by the very rich. Having purple garments became a symbol of wealth and power in the Roman world, the amount of purple worn being a measure of an individual’s importance. Throughout history the colour has been associated with royalty. Cinnabar was mined at Almaden in Spain to provide the Romans with the pigment. It was extensively used in wall decorations in the houses of the wealthy in Pompeii; gladiators and statues were painted with it and it was used by Roman women as lipstick. Its strength of colour meant that it was still being used in the 19th century, and is present in Turner’s paint boxes which remain and are held in various museum and gallery collections [1]. 5. Developments in the mediaeval and renaissance periods Fig. 5. Stacking White Lead (from Dodd, G. British Manufactures, 1884). Fig. 6. Red Lead manufacture in the 19th century. colours introduced by the Romans was Tyrian purple. It is mentioned in texts from 1600 BC and was obtained from the hypobranchial gland of the molluscs Murex trunculus and Purpura haemastoma which were found in the Mediterranean Sea near Tyre. Pliny described the ingenious process by which they were collected. A basket containing bivalves was lowered into the sea, which stimulated the bivalves to open. The molluscs would then be attracted to this source of food, but on attempting to eat the bivalves, the latter would close their shells trapping the molluscs which could then be The mediaeval palette and paintings were characterised by the use of clear, well-defined, bright colours. Browns seem to have held little interest for painters at this time and were regarded as dull. If required they were made by mixing black with red and yellow. The umbers first appeared in the late 15th century when Vasari described them as being new [7]. Umber comprises hydrated iron and manganese oxides. In its natural state it is known as raw umber and when heated it becomes a richer brown, known as burnt umber. Its original source was Umbria in Italy, although it is also mined in Devon and Cornwall. The Italians also used raw sienna, an ochre containing silicic acid, and raw umber, an ochre containing manganese oxide and iron hydroxide, both found in Tuscany, but especially in the Harz mountains of Germany. Raw sienna could also be calcined to produce the richer burnt sienna. An alternative to white lead used in the middle ages was bone white, made by burning bones and grinding the ash. Although it was not regarded as a good paint, it was used where the toxicity of white lead made its use undesirable [7]. Chalk, eggshells and calcined oyster shells were also occasionally used. For bright red, orange lead was a paler version of red lead prepared by heating white lead until it first turned yellow and then to the orange lead tetroxide. It was cheaper and more readily available than cinnabar. Confusingly the name minium was used for both orange lead and cinnabar. An artist working with minium was known as a miniator, who made miniature, so the term miniatures was originally used for the red capitals used in illuminated manuscripts. The term was eventually applied to any small feature and came to mean anything reduced in size. Other reds were made from insects (called ‘‘kermes’’ by the Arabs, a term which eventually mutated into ‘‘crimson’’), cochineal being an example, or from a type ARTICLE IN PRESS J.R. Barnett et al. / Optics & Laser Technology 38 (2006) 445–453 of wood called ‘‘brazil’’. The country was named after the wood as it was a rich source of dyewoods capable of producing the pigment. ‘‘Brazil’’ derives from the same root as ‘‘brazier’’ and is a reference to the red glow of the coals in the fire. The wood was powdered and steeped in lye (a solution of potassium carbonate), when the colour turns an orange red. Adding alum to the lye caused the pigment to precipitate. Madder, derived from the root of Rubea tinctorum, which contains alizarine, was also developed in the middle ages. At the time, however, the brazil reds were regarded as superior and were more widely used [7]. In addition to azurite, which had been used as a blue since the time of the ancient Egyptians, by far the most important blue in the middle ages was ultramarine. The name may reflect the strong blueness of the pigment, meaning that its colour was bluer than that of the sea, although it has been interpreted as meaning coming ‘‘across the seas’’ or imported [7]. It was made by grinding the semi-precious mineral lapis lazuli, a rock containing the mineral lazulite, and was used in Afghanistan in the sixth century AD (Fig. 7). Lazulite is a complex sulphur-containing aluminium silicate (Na8–10Al6Si6O24S2–4). During the renaissance, the colour blue was associated with purity and ultramarine was used to striking effect in paintings of the Virgin Mary, when she was almost invariably depicted wearing ultramarine blue garments. The high price of the pigment also meant that its use was appropriate in the case of a noble subject such as the mother of Christ. This colour therefore best characterises the paintings of that time. The lapis lazuli stone was ground, then mixed with wax and kneaded in a lye bath to separate the impurities 449 from the lazulite crystals. The pigment produced from these pure crystals was light-fast. The combination of the price of the semi-precious stones and the cost of the process meant that ultramarine was more expensive than gold. Malachite and verdigris were used as greens, although others were added, including sap green, which was made from the berries of Rhamnus (buckthorn). This was used, mixed with alum, to improve the colour of verdigris. There are also old recipes for making greens from a variety of other plants and it is likely that chlorophyll was the main pigmenting agent [7]. Orpiment and ochres continued to be used for yellow, although other exotic sources were used, including bile from the gall bladders of fish and other animals. Gallstones were also a source of yellow. Naples yellow was developed during the renaissance, although it has been claimed that it was present on tiles in Babylon from 16th century BC [4]. This is an opaque pigment comprised of lead antimonate (Pb(SbO3)2 or PbSbO4), the natural mineral bindheimite. It was manufactured during the renaissance by heating a lead compound such as the oxide or nitrate with an antimony compound (oxide or sulphide), or potassium antimonate. Gold substitutes were also used to reduce the cost of gilding in paintings. Tin sulphide was one such substitute which was known as mosaic gold and came into use in the early 15th century when it was called color purpurinus. Other substitutes included a mixture of egg yolk and mercury, to which was added saffron, bile or an extract from the greater celandine, Cheladonium majus. 6. Development of modern pigments Fig. 7. Lapis rock and Lapis pigment (from the Winsor & Newton Archive). The first chemically synthesised pigment was made in Germany in 1704 by Diesbach who was manufacturing red lake pigments by using potash and alkali as substrate. When using a batch contaminated with animal oil, he accidentally made a purple and then a blue pigment instead of the red he was trying to make. The blue became known as Prussian blue (Fig. 8). It has the unusual property of fading in daylight, then regaining its colour in the darkness. Ultramarine remained the most important blue pigment. However, the cost of ultramarine was so high that in 1824 the Societé d’Encouragement offered a prize of 6000 francs for the production of synthetic ultramarine whose price was to be less than 300 francs a kilogram, about a tenth of the current price for the cheapest Lapis Lazuli. Four years later the prize was awarded to Jean Baptiste Guimet even though his product cost 400 francs per kilogram. This pigment is the so-called French ultramarine, is chemically identical ARTICLE IN PRESS 450 J.R. Barnett et al. / Optics & Laser Technology 38 (2006) 445–453 Fig. 8. Prussian blue. to Lapis and remains an important and popular colour for artists. Cobalt features heavily in the development of some of the early synthetic pigments, with the combination of cobalt oxide with aluminium, phosphorus, tin, zinc and other metals giving a variety of colours. Smalt, a blue pigment comprising ground glass containing cobalt, was discovered before the 16th century and was made by heating quartz, potassium carbonate and cobalt chloride. It was replaced in the 19th century by cobalt blue, developed in 1802 by Thenard, partly as a result of studying the production of Sevres porcelain. Cobalt green was developed by Rinmann, a Swedish chemist in 1780 by combining cobalt and zinc oxides with an alkaline carbonate and heating the mixture. It was not favoured by artists, however, who found the pigment too weak. Cobalt violet (either cobalt phosphate or cobalt arsenate) appeared in 1859 and cobalt yellow (cobalt aluminium nitrite) was discovered by Fischer in Breslau in 1830 and first introduced as a pigment for artists’ use by Saint-Evre, Paris in 1852. Cerulean blue, a compound of cobalt oxide and tin oxide became available in 1805 and was marketed by Rowney in 1870. Zinc had been used in the manufacture of brass since that alloy was invented. However it was not until the 15th century that zinc metal was isolated and the end of the 18th century before the idea of using zinc oxide as a pigment arose. In 1834 Winsor & Newton of London, working with Michael Faraday, invented Chinese white after heating the oxide to increase its opacity. This gave water colourists the first semi-opaque water-colour white. However, George Backhoffer claimed that Flemish white (white lead) was superior. Fear of his influence on the market led Winsor & Newton to publish a response to Backhoffer, which was successful in persuading artists that Chinese white was the superior pigment. Cadmium metal was discovered by Stromeyer in 1817, and cadmium yellows were in use in Germany in 1829, France in 1831, North America in 1842, and the United Kingdom in 1846. Cadmium sulphide was mixed with an acidified solution of cadmium chloride or sulphate and heated with hydrogen sulphide gas. Hues ranging from a lemon yellow to a deep orange were made in this way. They were popular for their increased permanence, range of hues, moderate tinting strength and high opacity, which gave good covering power in painting. Cadmium red was available in Germany in 1907, England in 1912 and the USA in 1919. Indian yellow is an organic magnesium pigment, magnesium euxanthate (C19H16O11Mg
5H2O), which was used in India from the 15th century and discovered by western artists in the 19th century. It was made from the urine of cows fed exclusively on mango leaves. This diet led to the cows being weak and unhealthy and the practice was banned early in the 20th century, under pressure from Hindus, who considered the practice cruel to cows, which they consider to be sacred animals. The pigment is prepared as yellowish brown puree balls (Fig. 9), which according to Doerner [4], betray their origin by their odour! The coal tar pigment, naphthol yellow, was given the name Indian yellow by the trade when the original material fell from use. Fig. 9. Indian yellow, puree balls. ARTICLE IN PRESS J.R. Barnett et al. / Optics & Laser Technology 38 (2006) 445–453 Genuine emerald green was discovered by a Swede, Scheele, in 1788 and probably first commercially produced in Austria in 1914. It was very toxic, being composed of copper aceto-arsenite which gave a bright clean emerald colour, and was used until the 1960s. One theory holds that Napoleon’s death was caused by arsenic fumes from the wallpaper in his prison home on St Helena, which was coloured with this pigment. The rapid development of the science of chemistry during the 19th century was partly driven by the textile dying industry, and led to the development of many new pigments. In 1856, William Perkin, an eighteen-year-old student at the Royal College of Chemistry, was attempting to produce a synthetic alternative to quinine from coal tar. Following oxidation using potassium bichromate he produced a compound which when dissolved gave a purple solution [8]. Actually he had carried out an oxidation of aniline. The purple dye he obtained he called Tyrean purple, changing the name to mauvine, which later became mauve. This rapidly became the fashionable colour for ladies garments and Perkin as rapidly became a rich manufacturer of the dye. He had synthesised the first organic dyestuff and his success stimulated others to follow, leading to the production of other aniline/coal tar-based pigments and foundation of many of today’s leading chemical and pharmaceutical companies. Among the coal tar-based pigments made by one of these, the Hoechst company, is Hansa yellow, which has been said to be more permanent than cadmium yellow [4]. Alizarin crimson (1,2-dihydroxyanthraquinone) was synthesised by Graebe and Liebermann in 1868 in Germany (Fig. 10). This compound is identical with the coloured dye which had been extracted from the roots of the madder plant and the pigment is also known as alizarin madder. It has high tinting strength and high transparency. It is a popular pigment with artists despite its relatively poor permanence rating. This may be because of its traditional associations and because the Fig. 10. Alizarin crimson pigment (Winsor & Newton). 451 Fig. 11. Mars pigments in bottles, ca 1850 (Winsor & Newton). artists do not live long enough to witness its fading! Winsor & Newton still make Rose Madder Genuine from the root of the madder plant. Mars colours, which are synthetic iron oxides, were also developed in the 19th century (Fig. 11). They are available in a wide range of hues, from reds, browns, yellows and black which are produced by heating the oxide under controlled conditions. The final colour depends upon the amount of moisture and heat used in the process. These are particularly important as natural earth sources have been depleted. Lead white has been mainly replaced by titanium white (titanium dioxide). Titanium was identified in 1795, though it was not until 1920 that an economical method of purification was found. A non-hazardous, strong opaque white, it is very popular with artists. Monastral blue was first synthesised by A.G. Dandridge in 1928 and produced commercially by ICI in 1936. Dandridge observed a blue crystalline substance which formed during the production of phthalimide from ammonia and phthalic anhydride. The compound was phthalocyanine and was a result of a reaction between the iron vessel in which the reaction was taking place and the reactants. By using a copper container he produced a more intense blue now known as monastral blue or phthalo blue and marketed to artists as Winsor blue. In addition to being used by artists, it forms the colorant in inks, paints and lacquers [9] The 1950s saw the introduction of another very important group of pigments in terms of permanence— quinacridones. Derivatives of quinacridone produce red and violet pigments including permanent rose and permanent magenta. As the 1990s progressed more synthetic organic pigment types appeared. Perylenes, pyrrols and arylides appeared replacing light-fast pigments with even more ARTICLE IN PRESS 452 J.R. Barnett et al. / Optics & Laser Technology 38 (2006) 445–453 light-fast pigments. New hues have expanded the palette for water colourists and painters in oils and acrylics in terms of increased transparency, mixing or glazing. Like the textile industry in the 19th century, the car industry in the late 20th century became a major force for improvement of pigments. The painted surface of cars is exposed to extreme weather conditions and the pigments used in the colours need to be light-fast. A large variety of pigments are also demanded by manufacturers. This has led to spin-off benefits for artists. 7. Manufacture of pigments The earth pigments used by primitive humans were found as clays which could have been kneaded and shaped into ‘‘crayons’’ for use in painting and drawing. Such artefacts have been collected, for example, from Valle Caminica in Italy [1] and in the Lascaux caves [3]. It is clear, however, that there were early improvements to the simple mixture of coloured clay and water, to produce paints with improved properties. Analysis of the pigments from the caves at Niaux in the Pyranees showed that two distinct recipes were used for making up the paint, which included biotite, potassium feldspar or talcum. These would have acted as what are now called ‘‘extenders’’ or binders’’, making the pigment go further and improving its adhesive properties [9]. For much of recorded history, artists or their apprentices prepared their own pigments from the raw materials, which were mainly the minerals described above. The raw material was ground to a powder and, if necessary, the pigment was extracted in processes which are essentially unchanged to this day. Well into the 19th century, the paint boxes of artists, like those of Turner, which have been preserved in various museums contain jars of powdered pigment which would be mixed with a medium to make a workable paint that would bind to a substrate. Winsor & Newton still make Rose Madder in the traditional way, processing the roots to extract the dye. It is made into a ‘‘lake’’ by precipitating the dye onto a particulate material such as alumina. The material is filtered and dried to produce a fine powder pigment. All equipment used is made of wood or stoneware to avoid unwanted reactions with the dye, which might affect the pigment quality. Pigment and binder are then combined in a mortar and the mixture milled, sometimes for several days to ensure even pigment dispersion and that the pigment granules are as small as possible. This intensifies the colour as perceived in the painting. The artists of ancient Egypt and Rome mixed their pigments with media such as wax, egg or tree resin. By the 13th century, egg tempera painting, in which the pigment was mixed with water and egg before application, was well established. The dried protein left after the water evaporated bound the pigment to the substrate. The tendency of a thick layer of such paint to crack meant that it was essential to apply the paint in thin layers or glazes, and is the reason for the highly finished appearance of mediaeval paintings. In the 15th century egg began to be replaced by walnut or linseed oil as media. These dried more slowly than tempera and meant that the paint was more versatile. From the early 18th century colourmen appeared on the scene to provide artists with ready-made paints. Water colour painting also became a fashionable pastime among the well off. In 1766 William Reeves set up in business supplying water colour cakes. Reeves’ water colours were a significant improvement on those of his competitors as his discovery that the addition of honey to the colours prevented the cakes from cracking in storage. In 1783 the wigmakers Thomas and Richard Rowney abandoned the declining wig trade and began preparing and selling artist’s colours. Constable and Turner were among the famous artists they supplied with materials. A notable contribution by this company was the development of the first acrylic paints in the UK in 1963. The company of Winsor & Newton was founded in 1832 by William Winsor, a colour chemist and accomplished artist, and Henry Newton, a professional artist. This combination of talents meant they were able to bring a scientific approach to the development of pigments while being aware of the needs of the artist. Their development of Chinese white, the first opaque white water colour in 1834, has already been mentioned. In 1835 they also produced the first moist water colours (as opposed to dry block colours) by adding glycerine, then developing first glass syringes (1840) and then collapsible metal tubes with screw caps (1842) in which to sell them. In 1862 they introduced Aureolin yellow into the UK followed by Winsor yellow in 1899. Designers’ gouache paints were produced in 1937. New colours continue to be added to those available to artists. As recently as 1996, Winsor & Newton produced 35 new watercolours followed in 2005 by a further 15. 8. Pigments used today Although the focus of this paper has tended to be UK-oriented, reflecting the input of material by Winsor & Newton, the development of pigments has been, as we have tried to indicate, an international activity. One of the most prolific areas of publishing in colour is aimed at artists and those who appreciate art, a market which is truly international. A typical selection of recent publications [10–13] includes three published in North America. For example, Ames’s ‘‘Color Theory Made Easy’’[10], in an American context, involves descriptions ARTICLE IN PRESS J.R. Barnett et al. / Optics & Laser Technology 38 (2006) 445–453 of commercial products from what is necessarily a limited number of manufacturers, in which Winsor & Newton, a British manufacturer, is prominent. Artists today use a mixture of those modern synthetic organic pigments which have high permanence and intensity, and natural organic pigments and inorganic pigments which have stood the test of time. The pigments may be divided into earth, traditional and modern colours [14]. In the first group are the ochres, siennas, umbers and mars pigments; in the second are the metal based pigments, the cadmiums, cobalts, titanium and ultramarines, while in the third are the synthetic organic pigments such as the phthalocyanines, quinacridones, perylenes and pyrroles. Thus the relative cheapness and reliability of ochres used by prehistoric man mean that they are to be found on the palette alongside the natural organic pigment Rose Madder, developed by George Field 200 years ago, and the modern synthetic quinacridone pigments. Permanence is a sine qua non for an artist’s pigment and this is to be found in those pigments that have continued to be used throughout history, in many of the metal-based pigments and in the modern organics. The desire to leave a mark on the world for future generations is a strong part of human egotism which has driven the quest for pigments with permanence and intensity of colour. It will ensure a continuing market for, and drive research to provide, new and better pigments. Acknowledgements This paper is an expanded version of the presentation at the Colour and Design Conference by Sarah Miller of Winsor & Newton entitled ‘‘Colour and Art: a history of 453 pigments’’. The authors thank Winsor & Newton for supplying historical information and Simon Jennings for kind permission to use material from ‘‘Collins Artists Colour Manual’’ [15]. References [1] Finlay V. Colour: travels through the paintbox. Hodder and Stoughton; 2002 494pp. [2] Hamburger M. Isatis tinctoria—From the rediscovery of an ancient medicinal plant towards a novel anti-inflammatory phytopharmaceutical. Phytochemistry Rev. 2002;1:333–44. [3] Kritzon C. How to paint a mammoth. Bull.Primitive Technol. 2002;24. [4] Doerner M. The materials of the artist. Harcourt-Brace; 1984 435pp. [5] Robins G. The art of ancient Egypt. British Museum Press; 1997 271pp. [6] Elwood Madden ME, Bodnar RJ, Rimstidt JD. Jarosite as an indicator of water-limited chemical weathering on Mars. Nature 2004;431:821–3. [7] Thompson DV. The materials and techniques of mediaeval painting. New York: Dover Publications; 1956 239pp. [8] Copeland M, Larson D, Morton D. 2005. 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