VIRTUAL DEMONSTRATION
Casein paint

Add the caustic agent to the casein. You will probably notice a bit of heat and the formation of bubbles which is normal. In fact, milk casein is a protein which isn't soluble in water unless you add a caustic agent to it.

After this step, let the mixture rest until full dissolution of the casein. If you are using ammonium carbonate wait approximately 4 hours, 12 hours if you are using lime.