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A colour cast is a tint of a particular colour, usually unwanted, that evenly affects a photographic image in whole or in part.
Certain types of light can cause film and
Most digital cameras try to automatically detect and compensate colour cast and usually have a selection of manually set
Blue color cast - Compass 1.jpg
Blue color cast - Compass 2.jpg
Blue color cast - Adhesive labels 1.jpg
Blue color cast - Adhesive labels 2.jpg
Blue color cast - Paper sleeve with CD - 1.jpg
Blue color cast - Paper sleeve with CD - 2.jpg
digital camera
A digital camera is a camera that captures photographs in digital memory. Most cameras produced today are digital, largely replacing those that capture images on photographic film. Digital cameras are now widely incorporated into mobile devices ...
s to render a colour cast. Illuminating a subject with light sources of different colour temperature
Color temperature is the color of light emitted by an idealized opaque, non-reflective body at a particular temperature measured in kelvins. The color temperature scale is used to categorize the color of light emitted by other light sources ...
s will usually cause colour cast problems in the shadows. The human eye generally does not notice the unnatural colour, because our eyes and brains adjust and compensate for different types of light in ways that cameras cannot.
In film, colour casts can also be caused by problems in photo development. Improper timing or imbalanced chemical mixtures can cause unwanted casts.
Colour casts can also occur in old photographs due to fading of dyes, particularly under the action of ultraviolet
Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30 PHz) to 400 nm (750 THz), shorter than that of visible light, but longer than X-rays. UV radiation ...
light. These may be correctable on a scanned version of the photograph with image editing techniques.
Solutions
Most digital cameras try to automatically detect and compensate colour cast and usually have a selection of manually set white balance
In photography and image processing, color balance is the global adjustment of the intensities of the colors (typically red, green, and blue primary colors). An important goal of this adjustment is to render specific colors – particularly neu ...
settings to choose from. Otherwise, photo editing programs, such as Photoshop
Adobe Photoshop is a raster graphics editor developed and published by Adobe Inc. for Windows and macOS. It was originally created in 1988 by Thomas and John Knoll. Since then, the software has become the industry standard not only in raster ...
, often have built in colour correction facilities. For film, blue filters
Filter, filtering or filters may refer to:
Science and technology
Computing
* Filter (higher-order function), in functional programming
* Filter (software), a computer program to process a data stream
* Filter (video), a software component tha ...
and amber filters are used to counter casts. Amber filters are used to reduce the blueish tint caused by daylight. Blue filters reduce the orange colour caused by incandescent light.
A variety of coloured filters in varying degrees of intensity are available. Kodak
The Eastman Kodak Company (referred to simply as Kodak ) is an American public company that produces various products related to its historic basis in analogue photography. The company is headquartered in Rochester, New York, and is incorpor ...
's amber filters, for example, vary from palest yellow ("81C") to deepest amber ("85B"). A photographer chooses which filter to use based on the quality of the ambient light. Colour temperature
Color temperature is the color of light emitted by an idealized opaque, non-reflective body at a particular temperature measured in kelvins. The color temperature scale is used to categorize the color of light emitted by other light sources ...
meters can read the temperature of the existing lighting conditions and guide the selection of the filter. Clouded sky, for example, requires a paler amber than clear blue sky. If a filter is unavailable, flash
Flash, flashes, or FLASH may refer to:
Arts, entertainment, and media
Fictional aliases
* Flash (DC Comics character), several DC Comics superheroes with super speed:
** Flash (Barry Allen)
** Flash (Jay Garrick)
** Wally West, the first Kid F ...
is an alternative solution which usually provides enough neutral white light to counter the cast.
In the case of film, if photographs all contain the same cast, it is usually indicative of improper chemical development. If the film itself does not contain any cast, it can be reused to create another set of photographs in proper chemical conditions. If the film contains a cast, filters can be used during photo processing to correct it.
Gallery
See also
*Colour balance
In photography and image processing, color balance is the global adjustment of the intensities of the colors (typically red, green, and blue primary colors). An important goal of this adjustment is to render specific colors – particularly neu ...
* Colour temperature
Color temperature is the color of light emitted by an idealized opaque, non-reflective body at a particular temperature measured in kelvins. The color temperature scale is used to categorize the color of light emitted by other light sources ...
References
Image defects Color {{photography-stub