What is "opacifier"

n. 1 (label en chemistry) a chemical agent added to a material, such as rocket propellant, to make it opaque 2 (label en figuratively) an extraneous agent or vehicle which, intentionally otherwise, makes something opaque

An opacifier is a substance added to a material in order to make the ensuing system opaque. An example of a chemical opacifier is titanium dioxide (TiO), which is used to opacify ceramic glazes and milk glass; bone ash is also used.

Opacifiers must have a refractive index (RI) substantially different from the system. Conversely, clarity may be achieved in a system by choosing components with very similar refractive indices.