Term: Muller

A heavy stone or piece of wood, metal, or glass used to grind and mix pigment against a slab of similar material. A muller (typically glass) is used when making paint by hand. Mullers help grind the pigment to the desired level of refinement and to mix the pigment with binder to make paint. The base of a muller has a very fine roughness or tooth and is slightly convex to encourage the pigment to slide between the muller and the grinding surface.