How to make watercolour paint from plant colour
Watercolour paint is similar to any paint or ink – it consists of pigment and a ‘vehicle’, which is used to coat the pigment particles and ‘stick’ them to the paper. The vehicle is made up of a binder and, in commercial paints and inks, other additives such as filler and preservative. In watercolour paint, the binder is most often gum arabic which is obtained from two species of the Acacia tree, Acacia senegal and Acacia seyal. Gum arabic is widely available and comes in lumps, powdered form and in a pre-mixed, liquid form.
Lake Pigments and Dye Extracts
To make a dry, powdered pigment from plant matter can be complicated but is a useful method of obtaining colour from plants – please see my ‘Lake Pigment Recipe’ for instructions on how to do this. Other options include purchasing commercially-produced lake pigments or plant dye extracts from suppliers, both of which can be used to make paint – essentially anything that is a dry coloured powder can be used. Indigo is a great example of this and, as a plant with a long history of being used in artists’ materials and as a dye, has excellent lightfastness properties. As watercolour paints are water-based, you don’t necessarily have to start with a dry powder - a concentrated liquid colour is also fine but you would have to adapt your binder recipe accordingly.
Making the Watercolour Binder
Mix 2 tsp (approx 6g) of gum arabic powder with 4 tsp (approx 20g) of cold water. Add 1 tsp (approx 5g) of glycerin/glycerine and stir well. Leave in the fridge overnight to allow the gum arabic to completely dissolve in the water. This will make enough binder to make at least 6 half pans of watercolour.
Making the Watercolour Paint
Combine equal amounts of watercolour binder with your dry, powdered pigment using a small spatula. The ratio of binder to pigment needed will change depending on each specific pigment but 1:1 is a good place to start. You can add more pigment or binder as needed - I generally find it’s approx 1 part pigment to 1.25 parts binder. Once the pigment and binder are roughly combined, use your glass muller in a circular motion to disperse the pigment and make sure each particle is properly coated with binder. Add to your container and wait for the paint to dry.
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