A material that selectively transmits specific wavelengths thereby producing a restricted light spectrum from a full spectrum source. Light filters are available in several types, including color, reflective, ultraviolet, and neutral density filters. Color filters are typically made from glass of plastic and contain compounds that absorb specific wavelengths, or colors. Reflective filters typically have a reflective coating on a glass substrate that reflects the unwanted wavelengths. Reflective filters have sharp-edged filter bands and are often used for precision wavelength selection. Ultraviolet (UV) filters block ultraviolet radiation while letting the visible wavelengths pass. Neutral density filters provide a constant attenuation to decrease the intensity of all wavelengths.
Synonyms and Related Terms
light filtration; optics filter; optical filter; color filter; colour filter (Br.); neutral density filter; reflective filter; ultraviolet filter; UV filter; Fotografisches Filter (Deut.); optisch filter (Ned.);
Resources and Citations
- Olympus Microscopy: www.olympusmicro.com (Accessed Sept. 28, 2005)
- Wikipedia: http://en.wikipedia.org/wiki/Filter_%28optics%29 (Accessed Sept. 28, 2005)