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In image editing, a curve is a remapping of image tonality, specified as a function from input level to output level, used as a way to emphasize colours or other elements in a picture.
Curves can usually be applied to all channels together in an image, or to each channel individually.
Applying a curve to all channels typically changes the brightness in part of the spectrum. Light parts of a picture can be easily made lighter and dark parts darker to increase contrast.
Applying a curve to individual channels can be used to stress a colour. This is particularly efficient in the Lab colour space due to the separation of
Defanging the Curves Vampire
In image editing, a curve is a remapping of image tonality, specified as a function from input level to output level, used as a way to emphasize colours or other elements in a picture.
Curves can usually be applied to all channels together in an image, or to each channel individually.
Applying a curve to all channels typically changes the brightness in part of the spectrum. Light parts of a picture can be easily made lighter and dark parts darker to increase contrast.
Applying a curve to individual channels can be used to stress a colour. This is particularly efficient in the Lab colour space due to the separation of luminance
Luminance is a photometric measure of the luminous intensity per unit area of light travelling in a given direction. It describes the amount of light that passes through, is emitted from, or is reflected from a particular area, and falls withi ...
and chromaticity, but it can also be used in RGB, CMYK or whatever other colour models the software supports.
See also
* Blend modes * Image histogram * Hurter–Driffield curve *Tone reproduction curve In the theory of photography, tone reproduction is the mapping of scene luminance and color to print reflectance or display luminance, with the aim of subjectively "properly" reproducing brightness and "brightness differences".
The reproduction o ...
References
{{reflistExternal links
Defanging the Curves Vampire
Dan Margulis
Dan Margulis (born 21 December 1951) is an expert on color correction and reproduction of photographs, using Adobe Photoshop or similar software.
His ''Professional Photoshop'' series (first edition 1994, currently in its fifth edition, 2006) is w ...
, December, 1996
Digital photography
Image processing