Egyptian blue, was mankind’s first synthetically produced colour, invented in Ancient Egypt about 5,500 years ago, the same time that the Great Pyramids were built.
It was not produced by blind chance, but created with precision. Made from lime, copper and quartz and then kiln red at a crucial temperature of around 900 °C. It must be assumed that the Egyptians were able to control the ring conditions with amazing accuracy. Originally it would have been produced as a ceramic glaze for pots, an opaque deep blue glass. When this glaze was crushed up and ground into a fine powder it made the pigment.
It was widely used until about AD800 when, after the fall of the Roman empire, Egyptian blue fell from use and the knowledge of its creation was forgotten. The method of its production has only recently been rediscovered and the pigment re-introduced.
Derived from the Greek term meaning ‘from India’ it is a blue that comes from the leaves of the indiagofera tinctoria plant.
Indigo cultivation probably existed in the Indus Valley more than 5000 years ago, where they called it nila, meaning dark blue. It has been found in textiles and wall paintings in the Ancient World.
For many centuries it was the most important dye in the world. It helped support the British Empire as the indigo industry was its most lucrative export in Asia, used in vast quantities for such mass-produced items as military uniforms.
Synthetic indigo, developed in 1880, largely replaced the natural crop by 1913.
Lead Tin Yellow
If Lapis Lazuli is the king of the Rennaissence palette, then Lead Tin Yellow would be its queen. Used extensively by Vermeer, it’s distinct lemon hue was, until the introduction of Naples Yellow in the eaely 18th century, the most important yellow pigment for artists.
Discovered in the 13th century it was often used alone but also added to green and earth pigments for the creation of grass and foliage colours.
Also called ‘gialllolino’, it was produced by fusing lead, tin, and quartz at about 800°C, forming a yellow lead glass pigment that is ground and screened through a fine mesh.
Due to its high lead content, it is highly poisonous and was replaced by safer yellow pigments. The knowledge of its production was lost in the 19th century but was rediscovered in 1941.
The indigo molecule is also the blue colourant in the dye called woad, an extract of the plant Isatis tinctoria which is widespread in Europe and Asia.
Woad was widely used as a dye in northern Europe as early as the stone age. Famously, it was the colour with which the Celts decorated themselves to face the Roman legions.
At the beginning of the 17th century the importation of the more colour-intense Indian indigo ousted woad and production dramatically declined.