Optical Filters Color Temperature Orange (CTO) and Color Temperature Blue (CTB) Optical filters are a great tool for a wide variety of lighting applications. One common use of optical filters includes changing the correlated color temperature of a light source.

Light is a form of energy, which is radiated by heated bodies. The light is the part of the radiant energy which produces a sensation (of light) in the human eye. Luminous flux is the light energy radiated per second from a luminous body in the form of light waves. It is measured in lumen.