 Optimum quantity of binder provides a smooth surface at which all extender & pigment particles are tightly bonded by reducing little quantity of Binder can damage surface.However, at a certain PVC, called "critical PVC" (CPVC), the extenders & Pigments are already saturated with binder and the surface becomes solid and matt, without protruding particles; adding more binder (lowering PVC) will affect the sheen.CPVC generally depends on the binder-pigment system used, and generally falls in the 1–9% range.