Acrylic colors dry as a result of water evaporation. Here’s what occurs as pigment, water, and acrylic are transformed into a last-for-ages paint film:
Step 1:Squeezed from the tube, or scooped from the jar, acrylic paint is a finely balanced dispersion of pigment in an emulsion of acrylic polymer and water. The water serves to keep the emulsion liquid, and acts as a kind of chemical ‘chaperone’ preventing the acrylic polymer particles from getting close and personal and locking up before the artist is ready.
Step 2:When exposed to the atmosphere, water in the emulsion evaporates, or is absorbed into the painting support. That’s when the acrylic polymer particles come into direct contact and fuse with each other.