Derived from milk, casein paint dates all the way back to ancient Asian cave paintings.
Casein paint is durable, fast-drying, and water-soluble. It was also as widely used in ancient Egypt as tempera paint, and popular among commercial illustrators and muralists in the twentieth century. Many oil painters also use it for underpainting. Learn how to make it for yourself below!
Step 1: Mix 2 tablespoons of casein powder with 10 tablespoons of distilled water. Let the mixture sit overnight.
After sitting overnight, some of the water will have separated from the rest of the mixture.
Step 2: Discard the liquid that accumulated on the surface.
Step 3: Mix 1 tablespoon borax with 8 tablespoons of hot water.
Stir until the borax is dissolved.
Step 4: Add the casein mixture to the borax water and stir until smooth.
Step 5: Heat the resulting mixture in a double boiler on medium heat until it reaches about 180 ℉, stirring continuously. This heating process will take about 15 minutes. Let the mixture cool.
Step 6: Measure out a spoonful of Earth & Mineral Pigment (we used Yellow Ochre!) onto your glass palette. At this stage, some artists "pre-wet" their pigment with water–to do so, add a small amount of water to your pigment and mix with a palette knife until it becomes a thick paste.
Step 7: Mix a spoonful of the casein binder with the pigment on your palette. There is no exact ratio that works for every pigment; to test if your ratio is correct for the pigment you're using, apply your mixed paint to a scrap piece of cardboard. If some of the pigment rubs off after an hour, you need to add more binder. If the paint cracks, adjust the binder-to-pigment ratio by adding more pigment and water.
Step 7: Your paint is finished! Use this casein paint on wood, paper, or any rigid support, using water to thin the paint if needed. You can even prime your painting surface with "casein gesso" before using the casein paint–brush diluted casein binder onto your painting surface, then mix Natural Impasto Medium and Titanium White Earth & Mineral Pigment with the casein binder and apply.
Storage: To store the paint, keep it in a cool, dry location. To store the binder, store it in your refrigerator for up to 2-3 weeks.