Journal — Wild Inks & Colour

This is the sap from acacia trees. Gum Arabic helps: Keep the pigment suspended Makes the ink flow properly from a dip pen Helps stabilize black chemical compounds Without gum Arabic, you have a mixture that will separate and is difficult to write with. With gum Arabic, you have a stable, workable ink. (Thanks to Joumana Medlej for her elegant description of why we bother to use gum Arabic.) Basic recipe If you are working from lumps: In a saucepan, combine equal parts gum Arabic and water. Cook to dissolve. The final solution should be the consistency of double cream....

Chemical compounds are stored in plant cells. The colour-producing chemicals are called biochromes. The basics of extracting botanical colours In order to release these chemicals and make them available for ink, we crush and/or cook the plant materials in water to break down the cell walls. Once the chemicals are released from the plant cell, they become available to use as-is, or we can transform them to other colours by chemically altering their composition. Sometimes, simply exposing the biochromes to water, oxygen, and/or heat will transform them to different colours. Common biochromes and their sources There appears to be little...

Tannins are a family of chemical compounds found in plants. Different plants (and different parts of the plant) have different concentrations of tannins. E.g., galls > outer bark > sapwood. When mixed with iron, tannins form new chemical compounds (mostly importantly, ferric-polygalloyl glucose complexes). The chemical compounds are black, bond with paper, and are (relatively) waterproof after a few days. By adding gum Arabic, we protect these chemical compounds from degrading while in solution. Tannins fall into two groups of chemicals: Hydrolysable tannins Bonded sugar and water. Breaks down readily in water. Yellow-brown without modifiers. Black when iron is added....