Term: viscosity

Viscosity is a measure of a fluid's resistance to flow. In painting, it refers to how thick or thin a paint is. High-viscosity paints are thicker and flow more slowly, while low-viscosity paints are thinner and spread more easily. Viscosity affects how paint is applied (e.g., by brush, roller, or spray), how it levels out on a surface, and how it dries. Adjusting viscosity—often by thinning with water or solvent—is important for achieving the desired finish and application performance.