The Age Of Reason

Artistic styles ceased to be accepted without question, and art itself was no longer regarded as a craft; instead it became an academic subject.159 Painters no longer learned their skills with a master but instead would attend an academy of art, where they would methodically learn all the techniques of art from history. These academies began staging exhibitions in the leading cities of Europe, and buyers from polite society would attend and view the works on offer. Artists had to learn new skills in order to attract these buyers in an exhibition and many adopted bold colours and melodramatic themes to acquire attention. These changes in the place of art in society had many repercussions on the whole world of the artist.160 Traditionally artists had always produced their own pigments and paints. Recipes for these colours were handed down from master to apprentice over the generations, and were often closely guarded secrets. With the advent of art academies and an increase in the number of amateur painters simply painting for enjoyment, there arose a place for someone to supply pigments and colours to the art community.161 The new trade of the artist's colourman began, with businesses being set up to supply pigments, paints, brushes, canvases and all other materials to the professional and amateur artist alike.41,82

The beginnings of industrialization in Europe also influenced the world of art, and many dazzling scientific discoveries made in the field of chemistry rapidly unfolded to yield new and exciting pigments for the artist's palette.162 Artists were sometimes slow to take up these new discoveries, but as more new pigments were discovered the artist's colourmen really came into a world of their own.16

The Industrial Age

Advances in Chemistry

In 1770 a beautiful orange mineral named chrocoite was found in the mountains of Siberia, and it rapidly became popular with collectors in Europe. The French chemist Nicholas Louis Vauquelin (1763-1829)151 obtained a sample of the mineral and analysed it in 1797. He discovered that chrocoite contained an unknown element that formed a variety of intense red, yellow and green precipitates.164 The new element was named chrôme from the Greek word meaning coloured. Vauquelin initially had trouble procuring chromium ores, but by 1809 a source had been found in France, and the bright yellow pigment lead chromate was synthesized.164 Some time seems to have elapsed before the widespread production of chrome yellow for the artist's colour market. The first person to manufacture the pigment in England was a Dr Bollman (1769-1821)163, a German-trained medic, strongly influenced by the revolutionary ideas of Europe, who took part in several political acts and was exiled from Germany for a while, after which he eventually settled in England. Bollman became interested in manufacturing chemistry and set up a pigment factory on the Thames at Battersea producing, among other things, chrome yellow. The pigment was very popular indeed, and Princess Charlotte had her carriage painted with the flamboyant colour, which perhaps started the trend of the yellow taxi cab later in history.16

During the course of his experiments Vauquelin also discovered chromic oxide, and he published the first account of this green pigment in 1809.162 In this paper Vauquelin describes the manufacture of chromic oxide by calcining potassium dichromate in a furnace. Chromic oxide was being used in the ceramics industry at this time but was later introduced for artists' use; it was considered to be a very reliable green pigment with excellent fastness properties but poor colour strength. In 1838 the French colour maker Pannetier developed a stronger, more transparent variety of hydrated chromic oxide, known as viridian82, which became very popular with artists and is still widely used today.30 Vauquelin carried out many experiments with chromium and discovered several compounds that were also used as pigments.

French Ultramarine

Analytical experiments carried out at the end of the 18th century showed that ultramarine was composed of soda, silica, alumina and sulphur. By 1806 two French chemists, Desormes and Clément, had found that a blue impurity occurred in the slag of soda furnaces and had shown it to be chemically similar to ultramarine.162 This discovery led to a number of scientific prizes being offered to anyone who could devise a method of making artificial ultramarine. The Société d'Encouragement pour l'Industrie Nationale offered a prize of six thousand francs in 1824 to anyone who could make the pigment for less than three hundred francs per kilo.165 Four years later the prize was claimed by the French manufacturer Guimet who did not reveal his method.164 The synthesis of ultramarine was later published by a German chemist named Gmelin, who had discovered the method independently. Full-scale industrial production of the blue pigment was begun immediately16, and French ultramarine was widely used by artists.82 Natural ultramarine, however, is still considered to be superior for the purposes of fine art, despite its high price.

Green Pigments

Efforts to improve upon Scheele's green produced another highly toxic green pigment known as emerald green.82 This was copper acetoarsenite and was first manufactured commercially by Russ and Sattler in 1814. Emerald green was made by dissolving the pigment verdigris in warm vinegar, then adding a solution of arsenic oxide slowly to form a green precipitate. The precipitate was then boiled in fresh vinegar to obtain the bright green colour characteristic of emerald green.163 The pigment was a very popular colour but had only limited use in art due to its tendency to turn black on exposure to heat, and because of its highly toxic nature. Emerald green was widely used in wallpaper printing. A number of fatalities caused the poisonous nature of the pigment to be fully realized, and it then began to double as a highly effective rat poison in the home. On a slightly more sinister note, emerald green was featured in several murder cases, and unbelievably was still in use until the 1960s!166

Late 18th Century

Also working around this time were two English painters, Joseph Mallord William Turner (1775-1851)169,170 and John Constable (1776-1837)171,172, who were both landscape painters but adopted very different styles from each other. Turner produced fantastic, swirling land- and sea-scapes with strangely lit skies, while Constable set out to paint exactly what he could see with his own eyes. Constable was one of the first famous painters actually to go outside the studio and paint scenes using the colours he saw in the real world. He was not a popular painter at the time and was often criticized, which is surprising in light of his continued popularity today. Turner was, and still is, regarded as one of the greatest colourists. He is known to have used a wide variety of pigments. Analysis of his watercolour box has shown a large range of pigments, including several chrome yellows, cobalt blue, blue verditer, chalk, Indian yellow, red madder, yellow ochre, vermilion, red ochre, raw sienna, gamboge and carmine (presumably from cochineal, although the reference is not explicit).17 Turner used many of the experimental pigments of his time to great effect in his works.

New Pigments

Cobalt green was invented in 1780 by the Swedish chemist Rinman59,162, but was not widely used for about another 50 years. It was made by forming an aqueous solution of cobalt and zinc nitrates, then adding an alkaline carbonate and heating strongly to form a precipitate. The bright green precipitate had good pigment properties but fairly low colour strength.16 Cobalt green was only produced commercially after zinc oxide became widely available in sufficient quantities for the manufacture to become economic. It was introduced as an artist's pigment in 1835 and is still used today.

Coal Tar Colours

Perkin's purple product was the first synthetic organic colorant, named mauveine. It was tested industrially and patented.185 Perkin then rapidly resigned his academic position to set up as an entrepreneur of dyestuff manufacturing.1,186 The discovery occurred at a time when there was huge industrial expansion in Europe, particularly in the textile trade, and also a broadening of horizons as the rest of the world became more accessible to the average person.187 The Victorians acquired a taste for all things oriental, and purple became associated with oriental style.188 Consequently, mauveine became a great success as a dye and helped to set new fashion trends along with the crinoline, which had only been introduced three years earlier.189 Mauveine was not just popular as a dyestuff but was also laked to produce a widely used pigment.190 The bright purple pigment was popular with artists because of its unusual colour, and it was also widely used in decorative paints for the home by well-to-do Victorians. The discovery and synthesis of mauveine changed the world of colorants permanently.191

France in the 19th Century

French Impressionism

Early artists of this impressionist revolution included Edouard Manet (1832-1883)198,199, Claude Monet (1840-1926)200,201, Pierre Auguste Renoir (1814-1919)202,203 and Camille Pissaro (1830-1903)204. These men painted everyday scenes in a style that suggested form through the use of light and shadow, rather than defining shapes through gradual shading in the accepted style. They were subjected to much criticism and derision at the time and were even rejected from the official Salon exhibition of the Academie. The impressionists banded together to exhibit their work in the Salon des Refusés in 1864205, and many people went along simply to laugh at their efforts. This stormy period in art took about 30 years to pass before the impressionists gained popular acceptance and eventually became wealthy and famous. Indeed the impressionists are still regarded by most people today as ‘real art', which accounts for their amazing popularity.2

The impressionists used colour and light in a new way, and this was reflected to some extent by their choice of pigments.82 In the days prior to impressionism, many artists had chosen wide palettes containing a great number of pigments. The impressionists were more interested in studying the effects of mixing simple colours and lights, so often chose a simple palette of a few base colours. A study of Pissaro's palette showed that it was limited to seven pigments, all squeezed from prepared paint tubes.206 These pigments were: white lead, chrome yellow, vermilion, rose madder, ultramarine, cobalt blue and cobalt violet. This palette shows an absence of green and, more surprisingly, black, which would have been mixed from other colours.

After the acceptance of impressionism, the art world was changed forever, but was left in something of a quandary. Once the problems of imitating vision had been overcome, what was there left to solve? The post-impressionist painters were not content to continue painting as the impressionists, and were left once more to experiment with art.

Expansion of Organic Chemistry

The invention of aniline colours created a new drive to reform industrial practices and adopt a more organized approach to methods of production. The new industrial processes inadvertently led to the discovery of the third aniline colour in 1860.210 Magenta was being manufactured industrially in France using aniline and arsenic acid, and one day a workman in the factory seems to have confused the two chemicals. Instead of adding arsenic acid to the magenta reaction vessel, too much aniline was added by mistake, yielding a blue colour instead of the expected pink.211 Two chemists, Girard and De Laire, happened to observe this unexpected phenomenon, and later patented a method for the synthesis of a new blue colorant, which they simply named aniline blue.212,213 The chemistry of these new dyestuffs was not very well understood, but the dyes themselves were hugely successful.

Dominance of Germany

Alizarin Red

Madder is actually a mixture of many coloured components, of which alizarin is one of the most highly coloured and easily recognizable.34 Chemists throughout Europe worked on the puzzle of alizarin, but it was eventually a team of German chemists who made the crucial breakthrough and determined the correct structure.219 Their names were Adolf Bayer (1835-1917)220, Carl Graebe (1841-1927) and Carl Lieberman (1842-1914)221; they worked on alizarin from 1865 until 1868 and finally patented a method for its synthesis in December 1868.222 Industrial production of the synthetic madder, alizarin, began in Germany soon afterwards and caused the total demise of the natural madder industry throughout Europe.223

Synthetic Indigo

The industrial production of synthetic indigo did not begin immediately because of the difficulty in finding a production method economical enough to compete with natural indigo. Full-scale manufacture began in 1897, and this prompted competitive price decreases in the natural product.228 Once again indigo became highly politicized as the British government tried to defend its market.229 By the turn of the century the sales of synthetic indigo had overtaken those of the natural product, and the indigo plantations of India were suffering badly due to the crumbling of the British trade monopoly. By 1914 over 90% of all indigo used came from synthetic manufacturing routes.230 During this period laked indigo was very popular as an artist's pigment because it was easily available from two competing sources with the price dropping rapidly.231

The demise of natural indigo and madder marked the end of an era for natural colorants. It was no longer economically viable to grow plants, collect lichens or crush rocks to obtain colorants, so these small cottage industries tended to collapse. Some natural products remained for specialist applications, and some can still be found today, but on the whole they slowly vanished from use.

Beginnings Of Modern Art

The first of these artists was Paul Cézanne (1839-1906)233, who retired from the impressionist art world of Paris to live in the countryside. Cézanne painted scenes from nature but tried to keep the light and suggestion of the impressionists without losing the depth and distance of traditional art.234 He developed a system of building blocks of colours, which later influenced the style of cubism.235

The second artist was Vincent Van Gogh (1853-1890)236, who led a painfully disturbed and lonely life that ended with his suicide at the age of 37. His most famous paintings were all created during three years of intense activity and despair at the end of his life.237 Van Gogh painted in unconventional strokes and splashes of pure colour that make the paintings appear to move and also express the emotions of the painter. He even deliberately distorted images to achieve his aims. He died relatively unrecognized, but later was to have a huge artistic influence on the field of expressionism.238

The third artist was Paul Gauguin (1848-1903)239, a companion and colleague of Van Gogh for a time. Gauguin began to paint late in life after giving up his job as a stockbroker. He became disillusioned with the civilized art of France and eventually went to Tahiti to rediscover simplicity and even barbarity in his art. Gauguin used bold colour schemes and simple forms, often ignoring depth in his paintings.240 Later on the work of Gauguin strongly influenced the idea of a return to primitive art in Europe.

The era of modern art began with the influences of these three painters.241 Artists moved on from and absorbed the lessons of impressionism; they accepted that what we see is always influenced by our perception and by our pre-formed knowledge of what we are seeing. The human visual system and human mind are not perfect, and we can make ‘mistakes' in seeing. The theories of Charles Darwin (published in 1859) about evolution had begun to influence the way in which the people of Europe thought about humanity as a species.242 It was no longer entirely accepted that humans were the perfect creations of a divine being but rather that we had reached our present position by a series of evolutionary steps. Physics, chemistry and mathematics were also expanding in leaps and bounds151, with new and most unexpected discoveries being made on a regular basis. People were questioning their place in the world and even in the universe; they realized that there was a great deal still to discover. The experiments and discoveries of science were intertwined with and paralleled by those of art in the modern era.

An analysis of Cézanne's colour palette has been carried out.243 This showed that a wide range of pigments was being used at the turn of the 19th century. Cézanne's palette was comprised of 17 individual pigments, some of which had been recently discovered.82 The pigments were listed as: cadmium yellow, Naples yellow, chrome yellow, yellow ochre, raw sienna, vermilion, red ochre, burnt sienna, red madder, alizarin crimson lake, burnt lake, emerald green, verona green earth, cobalt blue, ultramarine, Prussian blue and peach stone black. The chemical identity of some of these colours is not clear.

Azo Colours

The first azo colours were not well understood chemically, but in 1870 Kekulé and Hidegh actively coupled diazonium salts to engineer azo dyes of known structure.216 The new azo dyes gave very bright, predominantly yellow, orange and red hues, which caused great enthusiasm and excitement. Many of these products were laked to offer an abundance of new pigments for artists, but unfortunately many of these pigments were not tested sufficiently for fastness properties.245 Artists became overwhelmed with bright colours, which often proved unsatisfactory for painting, having poor light fastness, or being fugitive in oils. Colourmen slowly implemented stricter testing procedures for artists' pigments, although many artists had already become disillusioned with the new discoveries, preferring to stick to the tried and tested pigments of antiquity for their paintings.246

True Organic Pigments

A famous family of azo pigments was introduced in Germany in 1911, known as the Hansa pigments.245 The first colorant of this group was synthesized by Wagner, called Hansa Yellow G. It was a very bright yellow pigment and was the first of many to be produced with great commercial success.

Cadmium Colours

In 1921 cadmium lithopones18 were introduced. These were manufactured by precipitation of cadmium sulphide with barium sulphate to give a yellow pigment. Experiments were also carried out with other materials to produce mixed cadmium pigments of varying hue. Cadmium sulphoselenides were introduced providing attractive orange and red shades.59 Mercury and cadmium pigments were also introduced to give other orange and red shades.253 All of the cadmium pigments were very popular with artists for all types of painting and drawing media, and some are known to have been used by Monet, Van Gogh and Matisse.254 Cadmium pigments are still being used today but are gradually being phased out because of concerns over the toxicity of cadmium.

Twentieth Century Art

Colour Classification

During the First World War there was a huge expansion of research and manufacture in colorants by the British and also by the Americans266, initially to aid the production of uniforms and equipment for the armed forces but also to develop technology comparable to that held by the Germans. From 1920 the Society of Dyers and Colourists began trying to devise ‘some means or other to systematize the nomenclature of the colours'.263 The first Colour Index was published in 1924266, followed by the second edition in 1956 in which the now well-established system of colorant nomenclature appeared.267 In 1998 an edition designed explicitly for the pigment industry was published.268 The Colour Index is still the only colour classification system that attempts to categorize all known colorants, and is invaluable to anyone with an interest in dyes and pigments. Most recently it has been released on CD-ROM. The development of a comprehensive colorants indexing system allowed chemical producers, dyers, researchers and artists to identify exactly what substances they were using.

Important Discoveries

The phthalocyanines were the first class of organic colorants to be introduced directly to the market as ‘true' pigments, without initially being developed as dyes or lakes. They were a new class of super pigments with incredibly high performance in terms of tinting strength, fastness and chemical resistance; thus they quickly came to dominate the blue and green pigment markets in all applications. In a very short time they had all but replaced the synthetic indigo lake pigment over which there had been so much political and economic turmoil only 20 years earlier. The phthalocyanines are immensely popular as artists' pigments and are used in nearly all pigment applications today.273 Indeed they are the most widely selling organic pigments at the present time.

The second important pigment to be discovered in the 1920s was white titanium dioxide.59 The white mineral rutile had been known for some time, but it was not until 1795 that German chemist Klaproth identified it as the oxide of a new element, which he named titanium.17,162 Naturally occurring titanium dioxide was not used as a pigment because it was too highly contaminated with iron and a suitable purification method had not been worked out. In the 1920s a suitable method of producing white titanium dioxide pigment was developed, known as the sulphate process.274 Natural titanium minerals are treated with sulphuric acid at about 200 °C to form a sulphate solution, which is then hydrolyzed to form a white precipitate of hydrated titanium dioxide. The precipitate is calcined in a furnace to form the white pigment with the correct properties. Titanium dioxide is nowadays often manufactured by another method called the chloride process and it is the most widely used pigment of all time. It is very safe to use, has the highest hiding power of all the white pigments, has excellent light fastness and is very popular in modern artists' colours, in addition to being very widely used in decorative paints, plastics, printing inks and many other applications.30

Modern Art

The cubist style was crucial to the development of a new movement of abstract art. Abstract artists were interested solely in the form of a painting and abolished reliance on subject matter altogether.280 Painters were free to study pure colours and our psychological responses to them. They began by looking at the human visual system and thought processes through experiments in art.281,282 The first abstract painter is considered to be Russian-born Wassily Kandinsky (1866-1944)283,284, who lived and worked in Munich. The scientific experimentation of cubism and abstract art were in some ways combined by artists such as Piet Mondrian (18721944).285,286 He built abstract pictures but out of solid forms, blocks of bright, primary colours and bold outlines, which probed the laws of vision and colour.287

Modern art tried to create new forms and to explore new ideas that had not previously been considered. In order to facilitate this creative process, many artists took a lead from Gaugin's primitive paintings of Tahiti and tried to return to a naive state from which to begin their work. Gaugin's work sparked a cascade of naive, childlike paintings and a great interest in folk art and the art of ‘primitive' cultures from the countries of the European empires.288 Naive artists, unlike the expressionists, were widely supported by both Nazi Germany and later by the Soviet Union. The concepts of naive art were absorbed and developed to found the Dada movement.289 This took the idea of returning to a childlike, primitive state to an extreme by rejecting all aspects of Western culture and conventional art.290 Many Dadaists used new materials such as discarded rubbish and waste paper in order to create their work, and many set out to shock the public out of their bourgeois art tastes.291 A leading Dadaist named Marcel Duchamp (1887-1968) became famous for exhibiting ready-made sculptures, which were commercially produced items, such as in one instance a urinal.292,293 Many of Duchamp's works were interactive with moving parts, and the public was invited to touch and feel the works in galleries. This began a trend for art being incorporated into everyday life, reducing some of the taboos and restrictions associated with attending an art gallery. The public was encouraged to obey their childlike instincts and investigate what they could see.

Being deliberately naive obviously caused problems, because it was not possible for any painter to adopt a primitive viewpoint all of the time or ‘unlearn' all of their knowledge and preconceptions. Naive art and Dada began to become increasingly fantastic and based less in reality.291 Many artists had been strongly impressed by the ideas of Sigmund Freud and investigated the concept that art cannot be created by waking reason. Painters deliberately set out to paint their subconscious thought; these artists became known as the surrealists.294 Perhaps the most famous surrealist painter was Salvador Dali (1904-1989)295, who tried to reproduce a dream world in his work. Dali's paintings are a confused mix of images, which cleverly blend into one another to form new images.296 Some objects in his paintings are illustrated with extraordinary clarity while some are deliberately vague and cannot quite be made out, like memories of a dream.

The American Art Scene

Before the Second World War the American artists of New York had taken great inspiration from the European art schools. Other influence came from the leftist revolution of Mexico (1911-20). In Mexico a great tradition of Socialist mural painting had been created that was sustained by state sponsorship.299 Famous fresco artists such as Diego Rivera (1886-1957)300 and David Siqueiros301 won international acclaim for their socially realistic work and even obtained commissions for large fresco works in America. Siqueiros set up a workshop near Union Square in New York. He introduced many young artists to his experimental painting techniques and to the use of new media such as industrial paints. The American stock market crashed in 1929 causing the great depression, and the artists of the day felt this intensification of social pressures, tending to become very politically minded.302 During the 1930s the Union Square area of New York became a hive of artistic activity reflecting these social issues, and a federal art project was set up. Thousands of artists were involved in this project and were paid a basic subsistence allowance to work and paint. The project generated hundreds of thousands of art works, and many of the young painters involved went on to form the New York art school. Such painters included Stuart Davis302, Jackson Pollock 303, Willem de Kooning 304, Lee Kranser302 and Mark Rothko305, who were all to become very famous during their lifetimes.

The New York School

The mingling of artistic and political influences caused the emergence of a new art movement that was centred in New York. In 1945 Peggy Guggenheim's gallery308 hosted an exhibition called ‘A Problem for Critics', where the art critics were challenged to identify the new style. The show featured works by many American artists302 including Hans Hofmann, Jackson Pollock, Arshile Gorky and Mark Rothko. These artists collectively became known as the abstract expressionists309, or the New York School, and for the first time American art led the world. The abstract expressionists were a group of individuals who had a great deal in common.310 They generally came from similar cultural and political backgrounds, and were all influenced by European modernism and the surrealists with an interest in the unconscious mind. They all believed strongly in individuality and denied being part of a group at all; they also objected strongly to the term abstract expressionism.

New Techniques

The American painter Mark Rothko carried out another novel investigation in art but this time with his use of colour.305 Rothko also had many different styles of painting until he settled on his mature style, which was often called colour field painting, which consisted of using large canvases filled with rectangles of colour painted in many layers to produce shimmering and glowing colour effects. Rothko did not title many of his paintings312 but simply gave them exhibition numbers or names such as ‘Composition in red and black'. The ideas behind these paintings were central to the abstract expressionists.302 It was felt to be important to remove the barriers of the conscious mind to allow art and free thought to come entirely from the subconscious, with a new perspective.

During the explosion of American art there were also a great many new pigments that were introduced by science and industry. The new artists took advantage of these new materials and often used them in interesting forms. The new organic pigments were bright, attractive and had good properties so were quickly adopted by the artists of the New York School.313 Many new painting materials were also developed after the introduction of novel synthetic-polymer systems and other technologies. In addition to the more traditional painting styles of fresco, watercolours, egg tempera, oils and chalks, the modern artists could choose from printing inks, emulsion paints, oil pastels, acrylic paints, coloured pencils, wax crayons, enamel paints, aerosol spray paints, etc. From this large selection of styles modern artists began creating collages or sculptures, and experimenting with art media using just about any material in their work.

Modern Pigments

Evidence of the quinacridone structure was first uncovered in 1896 but a linear quinacridone suitable for use as a pigment was not synthesized until Liebermann began work in 1935.315 He failed to recognize the potential use of this structure as a pigment, and it was not until 20 years later that any industrial progress was made. In 1955 Struve began investigating commercially viable synthetic routes to quinacridone pigments for the DuPont Company. The pigmentary potential of quinacridones was uncovered once it was realized that the quinacridone structure could exist in several crystal forms.316 The standard quinacridone could be converted to a very stable, highly coloured form, ideal for pigmentary applications. It took several years to perfect a synthesis, and in 1958 a new class of pigments was introduced into the market place.317 A wide range of quinacridone pigments are commercially available, but CI Pigment Violet 19 and CI Pigment Red 122 are two of the most important.

The last group of pigments to be introduced in recent times are the diketopyrrolopyrrole (DPP) pigments.314 These are ranges of organic pigments that are based on a specific type of heterocyclic chromophore discovered after a series of experiments carried out in 1974.318 The unusual heterocyclic compound produced was investigated by Iqbal at Ciba and eventually yielded an entirely new class of colorant, the DPP pigment.319 The exact date of Iqbal's discovery is not known since the work was carried out with great secrecy, but the new pigments were patented in 1983 when a synthetic production route had already been established commercially. Diketopyrrolopyrrole pigments are red and orange in hue and have all-around excellent pigment properties, which makes them desirable despite their high price. They have been used in some good-quality artists' materials and it is likely that their use may increase. Commercially, the most important DPP pigment is CI Pigment Red 254.320

Conclusions

Originally titled "A Colour Chemist's History of Western Art", published in Review of Progress in Coloration, Millennium Issue, Vol. 29, 1999, pp 43-64, Society of Dyers and Colourists, Bradford, UK.

Part 1 of this article ran in the January 2004 issue.

References