Coloured filters with a wide range of tones are used to block certain
wavelength ranges of the visible light. These filters absorb the blocked light
and are therefore insensitive to the angle of incidence.
Blue and green filters are bandpass filters.
Red and yellow filters are long-pass filters that pass light at wavelengths
longer than their characteristic cut-on wavelength – typically the wavelength
at which the transmission is 50% of the maximum. These filters use absorptive
glasses, that are robust, cost-effective and insensitive to angle of
In machine vision these filters are typically used in front of a lens on a
monochrome CCD or CMOS camera to improve image contrast. The appropriate type
of filter has to be selected with respect to the colour of the object and the
type and / or colour of the illumination.
Since they affect the composition of the transmitted light, they are usually
not suitable for use with colour cameras.
Unmounted filters for diameters from 10 mm to 74 mm
Mounted filters for common thread sizes M25.5 to M67
Different anti reflection coating options available