Microspheres are well known in the coatings industry for their use as low-surface-area fillers that offer benefits in viscosity and density control, solids content, application and flow characteristics. Cospheric LLC, a Santa Barbara-based microtechnology company, recently launched a line of opaque polyethylene microspheres that act as a superior opacifying agent and provide maximum hiding power with just one monolayer of microspheres as small as 40 microns in diameter. Microspheres are manufactured in any color imaginable and even in combinations of two differently colored hemispheres. When light strikes an interface between two substances, in general some may be reflected, some absorbed, some scattered and the rest transmitted. An opaque substance transmits very little light, and therefore reflects, scatters or absorbs most of it. High level of opacity becomes more difficult to achieve for microscopic particles, because opacity is proportional to the thickness of the material. An opaque microsphere does not allow any light to pass through, which means every single particle has maximum hiding power.