color filter

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Color filter

An optical element that partially absorbs incident radiation, often called an absorption filter. The absorption is selective with respect to wavelength, or color, limiting the colors that are transmitted by limiting those that are absorbed. Color filters absorb all the colors not transmitted. They are used in photography, optical instruments, and illuminating devices to control the amount and spectral composition of the light.

Color filters are made of glass for maximum permanence, of liquid solutions in cells with transparent faces for flexibility of control, and of dyed gelatin or plastic (usually cellulose acetate) for economy, convenience, and flexibility. The plastic filters are often of satisfactory permanence, but they are sometimes cemented between glass plates for greater toughness and scratch resistance. They do not have as good quality as gelatin filters.

Color filters are sometimes classified according to their type of spectral absorption: short-wavelength pass, long-wavelength pass or band-pass; diffuse or sharp-cutting; monochromatic or conversion. The short-wavelength pass transmits all wavelengths up to the specified one and then absorbs. The long-wavelength pass is the opposite. Every filter is a band-pass filter when considered generally. Even an ordinary piece of glass does not transmit in the ultraviolet or infrared parts of the spectrum. Color filters, however, are usually discussed in terms of the portion of the visible part of the spectrum. Sharp and diffuse denote the sharpness of the edges of the filter band pass. Monochromatic filters are very narrow band-pass filters. Conversion filters alter the spectral response or distribution of one selective detector or source to that of another, for example, from that of a light bulb to that of the Sun. See Absorption of electromagnetic radiation, Color

color filter

[′kəl·ər ‚fil·tər]
(optics)
An optical element that partially absorbs incident light, consisting of a pane of glass or other partially transparent material, or of films separated by narrow layers; the absorption may be either selective or nonselective with respect to wavelength. Also known as light filter.
References in periodicals archive ?
A colour filter is a transparent material that absorbs all coloured light except the one that is the same colour as the filter.
JVC claims it offers 'unprecedented high luminance and high resolution' through the use of a hologram colour filter produced by Dai Nippon.
The four colour filter (Red-Yellow-Yellow-Blue), Huawei removes the Green color filter and replaces it with two Yellow color filters to increase the camera's ability in low-light conditions.
However, unlike other apps that simple add a colour filter to photograph, the company says that it alters an image by combining neural networks, with artificial intelligence to achieve the desired effect.
'Pleochroism, the Dichroscope and Colour Filters' then examines the range of colour filters available on the market today, along with the typical dichroscope and Chelsea Colour Filter.
The resulting frequency division of colour enables a new type of colour display, which does not rely on colour filter wheels or dedicated blue and red pixels.
The Optical Filter Shop stocks a variety of band pass filters, colour filters, UV - IR filters and ITO, all of which can be selected by the shopper.
The applications include electronic packaging, touch panels and colour filters.
Research shows that visual stress from reading can be reduced by using colour filters in prescription lenses.
A total of 400 WE-EF fittings, with all their accessories such as ground-spikes, lenses, colour filters and connectors, were supplied and installed.
Special colour filters placed over pages can help children with reading difficulties read 25 per cent faster.