Natural binders like cave water, animal fat, blood, or marrow
Powdered color on its own brushes right off rock, so painters bound it with whatever was on hand: **cave water rich in calcium carbonate**, animal fat, blood, bone marrow, or plant juice. Some recipes even added bulking minerals such as ground quartz or crushed-bone powder, which kept the dried paint from cracking and helped it survive for tens of thousands of years.
