Iron Oak Gall Ink
This medieval ink starts with a wasp.
In spring, it punctures the soft young buds of the oak tree and lays her eggs. The tree, in response, forms little nutlike growths around the wasp holes, and it is these protective oak galls which form the basis of an intense black.
It was the standard writing and drawing ink in Europe from about the 5th century to the 19th century and remained in use well into the 20th century. The process was probably learned from the Arabs, who used it for ink, cloth dyeing and mascara.
In the UK it is still used in Registrars’ Ink for all official documents of birth, marriage and death certificates.
There was also an ink made from the soot of burnt beechwood or birch bark. Similar to asphaltum, it was a dark, tarry pigment called bistre.
It was not a new material, having been used in manu- script illuminations since at least the 14th century; but one needed skill and knowledge to make much of it in oils.
The nature of the ink is determined by the amount of resin that is present. The soot is mixed with distilled water and then cooked down to thicken. It is important to control the temperature of the mixture so as not to destroy the natural colour of the resin.
Used as writing ink from Ancient Roman onwards, it remained in common use as an artist’s drawing material until the 19th century.
Sepia is obtained from the ink sacs of cuttle fish. The sacs are extracted from the bodies and are dried to prevent putrefaction. The sacs are then dissolved in dilute alkali, and the resulting solution is filtered. The pigment is precipitated with dilute hydrochloric acid and then washed, filtered, and dried.
Only from Renaissance times onward, however, did sepia become popular as a drawing medium. In the late 18th and 19th centuries it was particularly popular and generally replaced bistre as a medium for making wash drawings.