What does "opacity" refer to when discussing paint?

Opacity in the context of paint refers to its ability to cover or conceal the surface underneath. A paint with high opacity will effectively hide the substrate's color and characteristics, providing a uniform appearance upon application. This attribute is crucial for achieving a solid and consistent color without needing multiple coats.

Unlike boiling down to drying time, which relates to how quickly a paint sets, or thickness, which pertains to the physical dimension of the paint layer, opacity specifically addresses the aesthetic outcome regarding visibility and coverage. Color intensity, while related, does not directly equate to how well the paint obscures the underlying layer. Opacity is an essential consideration in paint formulation and application as it influences both the results and efficiency of the painting process.