Before the introduction of commercially-made paints, artists or their apprentices would make paint from scratch using pigment and a binder. The first mass-produced watercolours were introduced in 1780 and were sold as hard cakes that needed to be dipped in water and rubbed to release the colour. At the beginning of the 19th Century, moist watercolours became available in porcelain pans and in 1846, tubes of watercolour paint entered the market (following the introduction of tubed oil paints in 1841). These advances were revolutionary and played a direct role in the development of the impressionist movement, as well as opening up new possibilities for plein air painting. Today, it can be difficult to imagine a time when artist colours were not available to buy readymade.
Some artists still choose to make their paints by hand which, while more time-consuming than picking up a tube from an art supplies store, is a great way of getting in touch with the properties of different pigments.
What are Watercolour Paints Made From?
Watercolour is made up of finely ground pigment suspended in a binder made of gum Arabic, distilled water, and other additives to preserve and stabilise the paint. Every watercolour manufacturer has a unique formula and method of production, which is why there can be such a difference in consistency and handling qualities between brands. Manufacturers of professional quality watercolours will also adjust the formula to account for the characteristics of each pigment in their range.
Artists who make their own paints have their own recipes which they will have fine-tuned over time. The following is a list of ingredients that I used to make handmade watercolours in the Jackson’s studio, some are available from jacksonsart.com, and others can be found in a supermarket or pharmacy.
Gum Arabic solution
Gum Arabic is a watersoluble gum which is extracted from the acacia tree, and it acts as the glue that binds the pigment. Some artists make their own by dissolving gum Arabic pieces in distilled water, but we also stock gum Arabic solution which is ready to use.
Honey is an ingredient in many ranges of watercolour, including our own Jackson’s Artist Watercolours. It is a humectant which helps the paint retain moisture and re-wet after drying. Honey is also a natural preservative and a plasticiser, meaning that it increases the flexibility of gum Arabic (a naturally brittle binder) and prevent cracking in the pan after drying. Runny honey is best, rather than the harder variety.
Like honey, glycerin is a humectant and a plasticiser which can be bought at a pharmacy (it is a common ingredient in skincare products). I used both honey and glycerin in my binder because I find too much honey to be very sticky, but either glycerin or honey would work on its own.
A natural antibacterial and antifungal agent, clove oil (usually sold as clove essential oil) is an excellent preservative which stops the paint going mouldy.
Our new range of Artist Pigments consists of 100 colours, all of which are suitable for making handmade watercolours. 10g is enough to make around 1-2 full pans of watercolour (depending on the pigment), so it is an ideal size if you are trying out a new colour. For larger volumes of paint, they are also available in pots of 100g.
Some pigments, like Cadmium and Cobalt pigments, are toxic and known to be hazardous when inhaled or ingested. Other pigments, like natural earth pigments, are considered less toxic, but no matter what pigment you are using, avoid breathing in the dust by wearing a face mask over your mouth and nose. Latex gloves should be worn to protect your hands, as pigment can easily get under your nails. Avoid eating and drinking around dry pigments and keep out of reach of children and pets.
Making Watercolour Paint
60ml of gum Arabic solution, one teaspoon of glycerin, one teaspoon of honey, and one drop of clove oil was decanted into a glass bottle and stirred well.
One tablespoon of dry pigment was placed in the middle of a tempered glass palette. Many artists who make their own paint prefer the grinding surface to have a fine tooth, and this can be created by making a paste with medium grit carborundum powder and water, and grinding it into the surface with a muller until the surface is frosted. This helps you mill the pigment extremely finely.
The pigment I used was Cobalt Cerulean Blue (PB36), one of my favourite pigments in watercolour because of its softly granulating properties. Using a palette knife, I made a well in the middle of the mound of pigment. With a pipette, I dropped 5ml of the pre-mixed binder into the well.
Using the palette knife, I gently folded the pigment into the binder, mixing as much as I could before adding more binder incrementally until all of the pigment was incorporated and the mixture had a yoghurt-like consistency. The amount of binder needed varies greatly depending on the pigment used, as some pigments are more ‘thirsty’ than others.
With a glass muller, I slowly ground the pigment/binder mixture in a circular motion, spreading it across the glass palette in a thin layer in order to grind the pigment as finely as possible. At this point, if the paint is too stiff to mill smoothly, more of the binding mixture should be added.
How long the paint should be milled depends on the pigment. Some pigments, like the natural earth pigments, have larger pigment particles and need more time to mill finely than those with smaller particles. I tested the paint along the way by taking a sample on the edge of the palette knife and swatching it. There are a couple of things to look out for when testing handmade watercolours.
- If the dried paint is dusty and smudges when you run your finger over it, it suggests that there is not enough binder in it, so it needs a little more binding mixture and more milling.
- If the paint is very shiny or cracks when you bend the paper, there is too much gum Arabic in the mixture and more pigment should be added.
Swatching is the most reliable way to know when to stop milling. The consistency is not so much of a good indicator, as some pigments make more fluid paint, while others make a heavier-bodied paint.
After around 30 minutes of milling, I was happy with the result. My first tests were a little chalky and very granulating, but as it was milled more and more, the Cobalt Cerulean Blue developed a slightly greener hue and had more clarity. Using a palette knife, I scraped the watercolour paint from the glass palette, and dispensed it into a full pan.
Handmade watercolours aren’t as smooth and creamy as shop-bought colours which are milled with a machine, but each has its own character! In the above image are three handmade watercolour pans with very different consistencies – Quinacridone Magenta and Natural Sienna Monte Amiata made heavier-bodied paints, as they have a higher pigment to binder ratio. Cobalt Cerulean Blue turned out more fluid and self-levelling. Regardless of consistency, each re-wetted well after drying. Some pigments, like earth pigments, have a tendency to crack when dry in the pan. Adding more honey and/or glycerin to the mixture can prevent or reduce cracking.
For larger volumes of paint, watercolour can be stored in a tube. To find out more about filling paint tubes, read our blog post on the subject. It focusses on oil paint, but the same principle applies and we stock 14ml empty aluminium tubes which are a good size for watercolour.
Watch our film to see watercolours being made in the studio:
Visit jacksonsart.com to find the materials used in the article:
- Jackson’s Artist Pigments
- Gum Arabic Solution
- Glass Palette
- Glass Mullers
- Palette Knives
- Empty watercolour pans
You can find other products related to watercolour painting, such as brushes, paper, and paints, in our watercolour category.