Over the past 5 years I have spent a lot of time trying to mix up the "perfect" natural paint. But all paint binders have their pluses and minuses. And a binder that is great for watercolor paintings may not work well for mask-making, where flexibility and moisture-resistance are of great importance.
Another factor to consider is how easy the paint is to work with. For example, an oil based-paint that is slow to dry and difficult to clean up may not be ideal for a children's mask-making class.
This document shares some of the paint binders I have been using. There is no one "perfect" binder here, but I hope the information will help you narrow things down if you are ready to paint your mask (or other art project) with natural paints but have been wondering what to use.
Most of the pigments I use are collected from nature (red volcanic earth, yellow mud-stone, white chalk deposits, etc.). If you don't have those things in your environment you can grind up bricks and campfire charcoal. I use a mortar and pestle to grind pigments, and a series of kitchen sieves of different hole sizes as pigment sifters. Or you can purchase ready-to-use natural pigments from companies such as Natural Earth Paint.
Once you have your pigments ready, you just mix them with a binder! You get to
chose how thick (or thin) you want to make your paint, and how finely ground
you like your paints to be. Sometimes I mix my paints in a dish-shaped seashell
with a paint brush. Other times I use a pallet knife on a sheet of tempered
glass. I might also use a glass muller to blend them extra well--but since I
like textured paint, quite often I don't.
1. Boiled wheat paste
Curiously, although it is flexible enough to paint on masks, I find it too rigid to use as a paper mache paste (I prefer methyl-cellulose paste for paper mache--although the cornstarch bio-plastic mixture shows some potential for paper mache too).
Mixing, painting and clean-up are all super easy, and it is perfect for teaching kids how to work with natural paints as well.
The main limitation is that it is not as moisture resistant as I would like. And sometimes adding subsequent layers of paint can cause the piece to feel sticky--I find placing it in the sun to dry fully takes care of this. But brushing on a final top coat of plain (un-pigmented) paste will improve moisture resistance and prevent smearing of colors.
Note: I did try adding linseed oil to a batch of boiled wheat paste paint to see if the resulting paint would be more moisture resistant. Unfortunately it did not help, and actually made the paint more easily smudged.
Boiled wheat paste paint summary:
Suitable for masks? Yes, but keep them in a dry environment.
2. Gelatin or hide glue
Gelatin/gelatine paint is really interesting to work with, but the paint has to be mixed and applied hot. This may be too much of a hassle for some, plus some may not like to use an animal hide and bone-based product. But what makes this paint binder special is moisture resistance, flexibility, and the fact that it dries (sets) fast. Apply in multiple thin layers for best flexibility. This is the one and only original "glue", traditionally used to build wooden furniture, gesso canvasses, and make composition trim and molding. The definition of "glue" has only expanded since the introduction of petrochemical-based synthetic adhesives.
The biggest challenge with animal glue is that if it is kept too hot for too long it will spoil (and usually unpleasantly). Once the dried material (gelatin powder or hide glue flakes) has been constituted, keep jars of glue or mixed paint refrigerated when not in use, or re-dry for storage. I like to add a few drops of clove oil to the paint, which seems to help prevent molding of stored jars. Woodworkers advise against re-heating animal glue due to reduction of strength, but for paint I haven't found that to be a problem.
When painting, I place a rectangular cake pan with an inch of water in it on an electric griddle, and set the jars inside that.
Gelatin paint summary:
Suitable for masks? Yes! But best if you have a lot of things ready to paint at once.
3. Egg Tempera
4. Oil paint
Oil paint is a classic. Flexible (unless applied very thick) and waterproof! But very slow to dry.
One thing to be aware of: any paint medium that contains oil will soak into and eventually damage paper. This is not an issue for painting on burlap (which is frequently already a little oily). But if you are painting on paper or paper mache, you might consider doing a non-oil-based paint or gesso layer first.
The addition of glycerin seemed to improve oil paint's adhesion to burlap, but glycerin didn't seem necessary when painting on paper.
Oil paint summary:
Suitable for masks? Yes, just allow for a long drying time.
Uses by book-binders and commonly sold as Elmer's Art Paste, it is a modified and biodegradable form of cellulose. It was my go-to paint medium originally, but the options listed above have since replaced it. It is easy to use and reasonably flexible. But it is not moisture or smudge resistant on paper, and although it works ok on burlap, it does not bind well with charcoal pigment. It is a great adhesive for making paper mache though!
Methyl-cellulose paint summary:
Suitable for masks? Yes, but there are better options.
6. Nopale / Prickly Pear Cactus
All versions of it were smudge resistant however, so I suspect it has some potential as a watercolor medium.
Nopale paint summary:
Suitable for masks? Sadly, no.
Big thanks go to my friend Scott Sutton AKA Pigment Hunter , who helped out so much with my natural paint journey, and who collected some of the pigments shown in the photos above.