The most prestigious pigment of the ancient world was actually made from a predatory sea snail. The dye is extracted from Murex brandaris, a mollusc native to Tyre in Phoenicia, now modern Lebanon, its production going back at least to 1500 BC.
In Greek legend it was discovered by Hercules, who, seeing the purple-stained mouth of his dog, realized it came from the shell fish the dog had just chewed.
Each shell fish yielded just one drop, an ounce of the dye required the sacrifice of around 250,000 shell fish. The putrid stench of thousands of decomposing snails meant that its manufacture was banished to the edge of town, the resulting shell piles of the Phoenicians still litter the eastern shore of the Mediterranean.
In the Ancient World it was strictly reserved for those of high rank. But in Imperial Rome prohibitive rules became so severe that only the emperor might wear ‘the true purple’ and extreme penalties were imposed for those not sanctioned to own purple garments.
An opaque bright red pigment of mercury sulphide occurs in a nature as the mineral cinnabar and has been in use from antiquity. The Romans, who loved cinnabar, sourced it from Almaden in Spain, the greatest mercury mine in the classical world.
Vermilion, the synthetic form, was invented around the 8th century. Mercury and sulphur are united through heat to form a red substance. In the Middle Ages its marriage of fundamental substances (sulphur was understood to be base gold) made it of incredible interest to alchemists.
The pigment was the principle red in painting up until the discovery of cadmium red in the 19th century.
Malachite green has been found in Egyptian tomb paintings from over 5000 years ago. The mineral is found in copper mines alongside its blue cousin Azurite, both being ores of copper carbonate.
To make into a pigment the natural mineral is carefully selected, crushed, ground to a powder, then washed and levigated by swirling in water to separate the green particles just as is done with gold panning. To be useful as a bright green it must be ground coarse, the powder becomes paler and more transparent the more finely it is ground.
Little used in the Middle Ages, it was an important colour in Rennaisance paintings of the 15th and 16th centuries but slowly lost favour and was replaced by the end of the 18th century with synthetic alternatives.
Painted as egg tempera or watercolor it is a pale green, but mixed with a drying oil it becomes darker and more transparent.
A cheaper alternative to Lapis Lazuli was the mineral Azurite (basic copper carbonate) found in deposits of copper ore.
Used since antiquity, Azurite is is the sister-stone to malachite, to which it is chemically related. Preparation of mineral azurite as a pigment was to simply grind, wash and sieve. When very finely ground, azurite is a pale sky-blue with a hint of green, excellent for skies, but inferior to the purple richness of ultramarine. If ground more coarsely, a deeper tone is achieved, but is very gritty, making the paint more translucent and difficult to apply so that many coats of coarse Azurite needed to be applied to achieve an opaque colour.
Azurite was the most important blue pigment in European painting throughout the middle ages and Renaissance.
It fell out of use when Prussian blue was discovered in the early 18th century.
Orpiment was one of the very few bright, clear yellow pigments available to artists until the 19th century and was a regular ingredient in the Middle Ages for painting and especially for writing as an imitation of gold.
Its very name recalls this connection: auripigmentum, ‘colour of gold’. In the ancient world it was believed that the superficial resemblance had deeper alchemical roots: that orpiment contained gold itself.
Orpiment is a sul de of arsenic, found in nature as a rock or a crystal and is highly toxic. Aware of its poisonous nature the Romans called it arrhenicum, from which the word arsenic is derived and the Romans used slave labour to mine it. For the unlucky slaves this was, in essence, a death sentence.
Realgar is an ancient pigment used in ancient Egypt and Mesopotamia. It was the only pure orange pigment until modern chrome orange.
A red-orange natural pigment closely related to yellow orpiment and the two minerals are found in the same deposits. Realgar was once widely used as a pigment because of its bright rich color.
It is extremely toxic arsenic disulfide, which limited its range of application and availability.
Realgar is not particularly stable and can also deteriorate badly in oil paint films, resulting in rupturing, cracking and chalking.
Verdigris is the common name for a blue-green pigment made, in a similar method to white lead, by suspending metal, in this case copper, over a bath of vinegar. Chemically it is copper acetate.
Used from antiquity, Verdigris was the most vibrant green available to painters until the nineteenth century. Verdigris was a popular but unpredictable pigment. The organic acids used to make it can attack the parchment on which it is painted.
In the 15th century an attempt was made to control its reactive qualities with the formulation of Copper Resinate. It was made from verdigris, combined with an oleo-resin. This new green was used enthusiastically throughout the 16th century, especially for glazing, but soon fell out of favour as it become evident that it rapidly turned brown. Many paintings of the Rennaisance have foliage and garments of dull umber colour as the verdigris has corrupted over time.
With the advent of Viridian in the 19th century, its use immediately declined. Today, it is only rarely sold as an artists pigment due to its toxic nature.
From white lead one makes red lead.
Artificially prepared since antiquity, it seems likely that the process was discovered by the accidental exposure of white lead to fire. Through roasting the white turns yellow, then a deep orange.
Red lead has been used by artists from antiquity until the nineteenth century. Known also as Minium, it was widely used in the Middle Ages for the decoration of manuscripts.
It can only successfully be used as an oil colour; as a powder and in fresco it eventually turns black.
Long after the Ancient Egyptians had stopped painting the tombs and sarcophagi of the pharaohs, the Chinese were also in need of a blue. They independently formulated and their own synthetic pigment, very closely related to Egyptian blue.
Chinese skill was based upon the use of the natural minerals available to them, replacing calcium with barium.
Paint found on the famous Terracotta Army of Xi’an, has found Han Blue dated to 2500 years ago.
The fact the Egyptians and Chinese were each able to develop an identical synthetic blue pigment indicates the advanced nature of their craft skills even though they had no knowledge of chemistry in the modern sense.