Artists have always been enhanced by blue, yet fine blues have long been difficult to obtain. Blues are relatively rare in nature, and painters throughout the ages have therefore found themselves at the mercy of what contemporary chemical technology could offer. Some blues have been prohibitively expensive, others were unreliable. The quest for a good blue has driven some crucial technological innovations, showing that the interaction of art and science has not always been a one-way affair.

The first pigments were simply ground-up coloured minerals dug from the earth. But few blue minerals are suitable as pigments – so there are no blues in cave art. Ancient Egyptian artists used blue prominently, however, because they knew how to make a fine artificial pigment, now known as Egyptian blue.

The discovery of Egyptian blue, like that of many other artificial pigments, was almost certainly an accident. The Egyptians manufactured blue-glazed stones and ornaments called faience using a technique they inherited from the Mesopotamians. Faience manufacture was big business in the ancient world-it was traded all over Europe by 1500 BC. Faience is made by heating stone ornaments in a kiln with copper minerals such as malachite. Egyptian blue, which was made from at least 2500 BC, comes from firing chalk or limestone with sand and copper minerals, and probably appeared by the chance mixture of these ingredients in a faience kiln.

Scientists recently deduced the secrets of another ancient blue: Maya blue, used for centuries throughout central America before the Spanish Conquest. This is a kind of clay – a mineral made of sheets of atoms – with molecules of the blue dye indigo wedged between the sheets. Using indigo in this way makes it less liable to decompose. No one has made colours this way since the Mayas, and no one knows exactly how they did it. But technologists are now interested in using the same trick to make stable pigments from other dyes.

The finest pigment available to mediartists was ultramarine, which began to appear in Western art in the 13th century. It was made from the blue mineral lapis lazuli, of which only one source was known: the remote mines of Badakshan, now in Afghanistan. In addition to the difficulty of transporting the mineral over such distances, making the pigment was a tremendously laborious business. Lapis lazuli turns greyish when powdered because of impurities in the mineral. To extract the pure blue pigment, the powder has to be mixed to a dough with wax and kneaded repeatedly in water.

As a result, ultramarine could cost more than its weight in gold, and medieval artists were very selective in using it. Painters since the Renaissance craved a cheaper, more accessible, blue to compare with ultramarine. Things improved in 1704, when a Berlin-based colour maker called Diesbach discovered the first “modern” synthetic pigment: Prussian blue. Diesbach was trying to make a red pigment, using a recipe that involved the alkali potash. But Diesbach’s potash was contaminated with animal oil, and the synthesis did not work out as planned. Instead of red, Diesbach made blue.

The oil had reacted to produce cyanide, a vital ingredient of Prussian blue. Diesbach kept his recipe secret for many years, but it was discovered and published in 1724, after which anyone could make the colour. By the 1750s, it cost just a tenth of ultramarine. But it wasn’t such a glorious blue, and painters still weren’t satisfied. They got a better alternative in 1802, when the French chemist Louis Jacques Thenard invented cobalt blue.

Best of all was the discovery in 1826 of a method for making ultramarine itself. The French Society for the Encouragement of National Industry offered a prize of 6,000 francs in 1824 to anyone who could make artificial ultramarine at an affordable price. The Toulouse chemist Jean-Baptiste Guimet was awarded the prize two years later, when he showed that ultramarine could be made by heating china clay, soda, charcoal, sand and sulphur in a furnace. This meant that there was no longer any need to rely on the scarce natural source, and ultramarine eventually became a relatively cheap commercial pigment (called French ultramarine, as it was first mass-produced in Paris).

In the 1950s, synthetic ultramarine became the source of what is claimed to be the world’s most beautiful blue. Invented by the French artist Yves Klein in collaboration with a Parisian paint manufacturer, Edouard Adam, International Klein Blue is a triumph of modern chemistry. Klein was troubled by how pigments lost their richness when they were mixed with liquid binder to make a paint. With Adam’s help, he found that a synthetic resin, thinned with organic solvents, would retain this vibrant texture in the dry paint layer. In 1957, Klein launched his new blue with a series of monochrome paintings, and in 1960 he protected his invention with a patent.

Australia’s Convict Colonies

A.  The 1700s in Britain saw widespread poverty and rising crime, and those convicted of crimes faced harsh penalties, including transportation to one of Britain’s overseas colonies. Since 1615, convicts had been transported to Britain’s American colonies, both as punishment and a source of labour, but this practice was halted by the Revolutionary War in America (1775-1783). The British government decided to establish a new prison colony, and Botany Bay in New South Wales was chosen as the site, (Captain Cook, exploring the southeast coast of Australia in 1770, had named the land New South Wales and claimed it for Britain.) Between 1787 and 1868, almost 160,000 convicts, of whom about 25,000 were women, were sent to Australia to serve sentences ranging from 7 years to life.

B.  Eleven ships set sail from England in 1787 to take the first group of about 750 British convicts to Australia. The fleet reached Botany Bay in January 1788, but nearby Sydney Cove was selected as a more suitable site for the new settlement, which later became the city of Sydney. The first few years were difficult, with severe food shortages; by 1792, however, there were government farms and ovate gardens. Convicts worked on these farms, or on construction projects such as building roads and bridges. Although the settlement was a prison colony, few convicts served their sentences in jail. They lived in houses they had built themselves, and established families, businesses and farms. A settlement was also established on Norfolk Island, where some convicts were sent for crimes committed after arrival in the colony. Two more settlements were established on Van Diemen’s Land (now Tasmania), in 1803 and 1804.

C.  Convicts not involved in public work were assigned to free settlers, providing labour in exchange for food, clothing and shelter. Some masters treated the convicts cruelly, and the punishment of convicts, particularly in the early days, could be arbitrary and savage. Lachlan Macquarie, governor of New South Wales from 1809 to 1819, adopted a more humane approach. He encouraged convicts to reform by rewarding good behaviour, even granting pardons to convicts before their sentence was completed. These emancipists, as they were called, were given land and government assistance to help them start farming. His policies were unpopular both with British authorities and wealthy free settlers, however, and the next governors were under orders to ensure that life for convicts became much stricter and more controlled. There were harsher punishments for second offenders, such as working in the ‘iron gangs’, where men were chained together to carry out exhausting work on the roads, or being sent to penal settlements where punishment was deliberately brutal so that it would act as a deterrent.

D.  In the early years of settlement, the convicts greatly outnumbered free immigrants and settlers. In 1810, convicts made up almost 60 percent of the population, and over 20,000 new convicts arrived between 1821 and 1830. Even in 1831, convicts still comprised 45 percent of the population, with ex-convicts and emancipists making up another 30 percent. 25 percent of the population now consisted of people born in the colonies, and free people outnumbered convicts.

E.  The first group of free settlers had arrived in Australia in 1793 to seek their fortune in the new land. Their numbers grew, with about 8,000 free settlers arriving in the 1820s to take advantage of free land grants and cheap convict labour. In 1831, the British government offered money to support new settlers, hoping to attract skilled workers and single women as immigrants. Between 1831 and 1840, more than 40,000 immigrants arrived in Australia.

F.  During the 1820s there was a lengthy campaign to win certain rights for emancipists, which was opposed by wealthy free settlers. In the 1830s, free immigrants to New South Wales and Van Diemen’s Land, unhappy about living in a prison colony where civil liberties were restricted and convict labour resulted in low wages, increasingly voiced their opposition to transportation. Again, wealthy landowners disagreed, but a growing number of reformers in England were also opposed to convicting transportation. In 1838, a committee set up by the British Parliament recommended that the government end transportation to New South Wales and Van Diemen’s Land, and abolish assignment. The British duly abolished assignment, and transportation – at least to New South Wales – was halted in 1840.

G.  Transportation continued, however, to other colonies and settlements. In the 1840s, most British convicts were sent to Van Diemen’s Land, where the British government introduced a convict system based on stages of reform, with the convicts gaining increasing levels of freedom for continued good behaviour. Transportation to the eastern colonies was abolished in 1852. In contrast, the convict system in Western Australia began in 1850, at the request of the Western Australian government, and continued until 1868. Convicts served part of their sentences in Britain before being transported to the colony, where they worked on badly-needed public construction projects under a system similar to that tried in Van Diemen’s Land.