The production of natural paint or ink is done in two steps: First the dyestuff, consisting of colourants or pigments, has to be extracted from the plant. After that, a binder can be added, depending on the desired application.
There can be big differences between plants on the method of extracting the dyestuff. On the one hand this is because dyestuff from different parts of the plant is used; on the other hand, the chemical background of the dyestuff plays a role. An example is the red/purple colourant that is harvested from the plant Alkanna tinctoria. This colourant (alkannin) is a napthoquinone. Colourants in this chemical group are often not or slightly soluble in water; when extracting this colourant from the plant, it’s better to use oils.The chemical background of each of the colourants is noted at the plant information, with the recommended solvent. When the complete procedure of a plant has been researched, the plant-specific findings will be added to the website. Take caution: as stated at the cultivation of plants, poisonous painting plants exist as well. Always process dyestuff separate from places where food is prepared.
For colourants soluble in water we can form a general recipe. Note, the method can differ per plant. Whenever there’s knowledge on this available, it will be published on the pages about the respective plants.
- The part of the plant that contains the colourant can be harvested fresh or dried after harvest for later use.
- The surface area of the material can be enlarged by grinding or cutting the material. This makes extracting the colourants easier.
- Next, the material needs to soak for a few hours or a night and optionally, cook.
- The fluid is sieved to separate the ‘pulp’ and the water now containing the colourant.
- This fluid can be boiled down in a bain-marie to a higer concentration of the colourant. By boiling it down to a dry mass, the colourant can be preserved better.
The obtained colourant can be used for experimentation. Some colours become more saturated by using natural substances like zucchini-, cucumber- or pumpkin-juice. The brightness of the colour can be influenced by changing the acidity, using for example vinegar, lemon juice or soap.
Some pigments aren’t soluble in water. Other methods are needed for extraction of these colourants. For an example, see the paint recipe for woad (Isatis tinctoria).
Colourants solved in water can be used as ink without any additives. Though often a binder is desireable, when using dry pigments or dried colourants, for example. A binder can also help get the right viscosity for silk-screen or lithography. Natural substances are used as binders as well. Below a list with a number of properties per binder:
|Binder||Viscosity||Solubility||Dilute yes/no||Other properties|
|egg||very viscous||colourants dissoluble in water||no||creates gleam, dries quickly|
|Arabian gom||adjustable by adding water||colourants dissoluble in water, pigments||yes, with water||creates gleam, works well with silk-screening|
|starch/carob flour||adjustable by adding water||colourants dissoluble in water, pigments||yes, with water||dries well & white, so colours turn out lighter|
|agar agar||adjustable by adding water||colourants dissoluble in water, pigments||yes, with water|
|stand oil||averagely viscous, adjustable by adding linseed oil||colourants dissoluble in fat||yes, with linseed oil||experimentation with other oils is possible|
|olive oil||very viscous||colourants dissoluble in fat||no||usable as extraction substance as well|
|tragacanth||adjustable by adding water||colourants dissoluble in water, pigments||yes, with water||white, so colours turn out lighter|
|kuzu||adjustable by adding water||colourants dissoluble in water, pigments||yes, with water||transparant, so the saturation of the colours stays the same|
|arrowroot||adjustable by adding water||colourants dissoluble in water, pigments||yes, with water|
Per binder experiments are carried out to discover which binder works best for different applications. The findings of these experiments will then be published on this website. Below some pictures of adding a natural dye (in powder form) to Arabian gom: