It diffuses incident light evenly and has characteristics similar to a Lambertian light source. Higher diffusion than rubbed glass. The milky white tint is not due to the opal coating, but to the glass itself. Spectral transmittance can be adjusted by changing the thickness. When the glass is thin, it can be laminated with Tempax material to increase strength. UV transmittance opal diffusers are under development. (The red dashed line in the graph on the left is the characteristic of the opal diffuser.)

Alternative to Schott's opal glass"Opalika "(Discontinued).

* IOP series are in the process of being patented.