NEUTRAL DENSITY FILTERS
GREY FILTERS FOR ARCHIEVING HIGHER CONTRAST IN THE VISIBLE RANGE
Neutral density filters are characterised by a near constant transmittance in the visible range of 400 - 700 nm. The degree of transmission depends upon both; the different NG glass type and the thickness. For filtering tasks that requires a fixed attenuation, specifically tailored neutral density filters are available.
A neutral density filter can be described by transmission t or absorption as optical density D (D = lg 1/t).Specifically designed neutral filters are available for applications that require a defined attenuation.