“How is blue paint made?”

Historically blue was very hard to make and very expensive to make and so was a colour associated with the wealthy and elite. The famous pigment Ultra Marine came from a stone that could only be found in Afghanistan called lapis lazuli.

In order to turn lapis lazuli into a blue pigment, it had to be brought all the way along the Silk Road from Afghanistan and then ground down to create this blue pigment. Ultra Marine was probably first devised in the Middle Ages in Italy and was 100 times more expensive than most other pigments on the market, and was more expensive than gold in some cases. As an artist, if you wanted to depict someone who was splendid and powerful and important, you would often depict them in blue clothes. 

The Egyptians were absolute masters of chemistry, and they were able to create the very first synthetic pigment in history in about 3300 BCE and that was a blue pigment called Egyptian Blue. It was made from copper, calcium and silica.

The Egyptians also had a blue dye called indigo which is extracted from the leaves of the indigo plant. The leaves are harvested, dried and ground into a powder. These plants contain a colorless chemical that turns blue after being extracted and exposed to oxygen in the air.