Neutral Density Absorption Filters

Neutral density absorption type filters decrease the intensity of light without altering the relative spectral distribution of the energy, attenuating the visible spectrum evenly without influencing color or contrast. Attenuation is accomplished by using a light-absorbing glass. Optical density varies from 0.1 to 3.0; 1 and 2 inch round and square filters are available, mostly uncoated, with some versions for near-IR wavelengths.