Water colour binder recipes are as varied as cake recipes, they can range from basic to extravagant and everything in between. While the ‘best’ recipe comes down to personal preference, there are still a few basics that need to be followed.
Water colour binder is primarily made up of Gum Arabic, which is the hardened sap of the Acacia tree. The gum or sap is produced by the tree as a result of injury to prevent infection and thereby protecting the tree. Other stoned fruit bearing trees that have a water soluble sap can be used, for example cherry, however depending on the cerasin content of the cherry gum which depends on the time of year harvested, it is not always the easiest to dissolve and the results aren’t always reliable. The gum arabic dissolves in water and enables the pigment to disperse evenly in the suspension and binds the pigment to the surface. The gum arabic alone however produces a few problems, one is that is that it is likely to produce cracks on the paint and the other is that it can be difficult to re wet the pan of paint.
Glycerin is then added to the solution. Glycerin is a humectant which attracts water from the atmosphere enabling the pan paint to re wet and reactivate. It also stops the paint from cracking on the surface of the paper as it keeps it softer. Not enough glycerin in the binder can result in a dry and flaky paint, and too much can result in the paint not drying properly on the paper and staying tacky.
Honey is another humectant which can be used in place of or in addition to the glycerin that helps the paint to flow. As honey is anti drying, it can prevent the pan of paint from drying out completely. Some people prefer working with the paint wet, as in straight from a tube, while others like myself, prefer a pan that has dried out and been re wet.
Clove essential oil (Rosemary or Wintergreen essential oils also work) is added as a fungicide to prevent the paint from going mouldy.
A lot of paint makers are reluctant to give out their exact recipe for a number of reasons, one being that it can take a lot of time, effort, money and research and experimentation to find the recipe that they personally like. Another is that what one person likes another will not so they will think the recipe is wrong. The final reason is that it is through the experimentation process that we learn and truly find what works for us. To that end, I would encourage you to try several different recipes, experiment and see what works best for you. I live in a cold, humid country where we struggle to get pans to dry, so our recipe reflects that. If someone in a hot dry country used the same recipe as me they might hate it as it would probably dry too hard and crack. Experiment and learn.
A basic recipe is to start by making up a gum arabic solution. Gum arabic can be bought in crystal form which is harder to dissolve, in powdered form which is what I use and recommend, and pre-made. The powdered form is the more cost and time effective option in my opinion. Using a ratio of 2:1, water to powder, dissolve the powder in warm, preferably distilled water, and mix well to prevent clumping, although the clumps will eventually dissolve out. Leave for 24 - 48 hours.
I use 40g water and 20g gum arabic powder and to that I add 10g glycerin. This amount can be increased or decreased based on preference, but not always by much. This by itself produces a lovely binder that is suitable to use, but I prefer the addition of 5g honey and then I add 2 drops of clove essential oil.
20g Gum Arabic Powder
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