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Colour begins with chemistry

We have a long history with art. Paintings, sculptures, and dyed clothing date well back before modern civilization took hold. Every culture around the world has engaged in art of some form.
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We have a long history with art. Paintings, sculptures, and dyed clothing date well back before modern civilization took hold. Every culture around the world has engaged in art of some form.

Western art can be dated back to Mesopotamia and ancient Egypt. And it is their art which leads to the Egyptians being considered the first chemists. They conducted chemical transformations hardly less refined than European chemists 4,000 years later.

Early artisans developed the firing of clay to produce pottery in high temperature kilns. Out of these came the invention of glazing, enamels, glass and metallurgy. The use of silicates generated glazes but freed from the underlying clay led to the development of glass. Inclusion of minerals resulted in coloured glasses and the accidental firing of the minerals by themselves would have resulted in the metals in their raw form. For example, the mineral malachite is an easy source of copper metal while also finding use in green paints.

Around 2,500 BCE, the blue pigment called Egyptian frit was being produced in large quantities. The recipe wasn't a simple accident but required careful precision with one part lime or calcium oxide (which itself was generated from limestone or calcium carbonate), one part malachite and four parts quartz or silica. The raw materials were ground together and fired at a temperature between 800 and 900 C. The temperature was actually quite critical or the results are not the desired blue pigment.

This blue added to the colour palette of ancient artists. It shows up as a substitute for the semi-precious gemstone lapis lazuli and was even used to coat sarcophaguses. The generation of pigment was a highly specialized knowledge requiring skill and experimentation. For example, the yellow pigment lead antimonite requires lead oxide or carbonate and antimony oxide as starting materials. These compounds were obtained by chemical transformation of minerals.

The Greeks and Romans used colour in decoration. Modern analysis of structures such as the Parthenon and sculptures such as the Venus de Milo indicate they were once brightly painted. The white stone we see know is a consequence of the paint slowly being weathered away. Greek and Roman houses featured coloured walls and tiled floors with incredible mosaics.

In the middle ages, the colour palette in Europe expanded slowly. There are a number of reasons behind this but primarily it was due to a lack of cohesive chemistry and a slavish adherence to painting with pure pigments. The blending of colours to produce a richer range was frowned upon and at various times forbidden by painters guilds.

This was not so in the Middle East and the Orient where elaborate works of art flourished. Much of modern chemistry owes its origins to Persian alchemists who refined the craft and developed compounds unknown in the west. Indian dyers developed colours well outside of the European palette which were only slowly introduced into much later artwork.

It was through the crusades and trade across the Mediterranean that colour pigments drifted out of Asia and onto the artist's canvas. Venice played a critical role as a gateway and it is perhaps not surprising the Italian Renaissance saw such magnificent artistry. Colours, such as ultramarine, vermilion and lead white were featured in paintings. Interestingly enough, colours were still not mixed but glazed one over the other to give varying hues. Transparency was critical to many great paintings.

By the end of the 1700s, chemistry had become well-established as a discipline although its technical nature and connection with the material world often left the impression it was not a true science. Nevertheless, its role in the development of art remained firm as William Cullen contended in 1766: "Chemistry is the art of... producing several artificial substances more suitable to the intention of various arts than any natural productions are."

In the early 1800s, artists were admonished to learn a little chemistry and anatomy but to not dwell on the subjects. So in 1832 Winsor and Newton set up shop in London to provide the paints required by professional and amateur artists alike. The generation of colour had moved into the industrial age. Many modern chemical companies such as Bayer, Hoechst, and BASF began by generating dyes and pigments primarily for the clothing industry but also for use by artists.

In the mid-1800s, a whole new range of colours arrived on the scene. Mauve was synthesized as an aniline dye from coal tar by William Perkins and his work led to many imitators generating a wide variety of compounds. The modern pharmaceutical industry actually arose, to some extent, from the chemist's labs as they pursued better and more diverse ways to make coloured compounds.

Chemistry is the art of transforming matter. It has a long history associated with the transformations necessary to make the wide variety of pigments and dyes used to colour our world.