color space

(redirected from Colour spaces)

color space

A system for describing color numerically. Also known as a "color model," the most widely used color spaces are RGB for scanners, cameras and displays, CMYK for color printing and YUV for TV/video. Prior to the proliferation of electronic displays, which are all RGB, color spaces were developed that were closer to the way people think about color. For example, the CIE Lab model uses lightness (L) and values on red-green (a) and blue-yellow (b) axes, while HSB uses hue, saturation and brightness. See CIE Lab, HSB, HSL, RGB, sRGB, YUV, xvYCC and color space conversion.


HSB, CIE Lab, RGB and CMYK
All four color spaces in this Photoshop color picker relate to each other. Although numbers can be entered, users mostly move the vertical slider or point into the box to select a color. In this example, the R in RGB is selected, and moving the slider changes Red from 0 to 255 and all related values in the other color spaces at the same time.







A More Intuitive Model
In the 1970s, Alvy Ray Smith developed the HSB model for color selection. Changing red to pink by reducing saturation (S) is more intuitive than changing green and blue in RGB. For details, see HSB. For invaluable information about color spaces and computer graphics (CG) from one of the country's most distinguished experts, visit www.alvyray.com, and click Papers and CG.







Color Space Conversion
Since displays, printers and TV/video all use different color spaces, conversion between them is necessary and commonplace.
References in periodicals archive ?
Each will use recent projects to illustrate how they have addressed the challenges of moving between colour spaces and show the latest grading tools in action as well as practical workflows -- from on-set to finishing.
Sanchez-Perez, "Detecting skin in face recognition systems: A colour spaces study", Digital Signal Processing, vol.
The existing body of studies on skin colour segmentation has suggested the use of colour spaces to perform human skin segmentation by particular skin colour threshold [3-5].
The ageing results obtained from Spectrophotometer Datacolour presented detail of colour spaces for views of ageing factor in the coating film.
Additionally, full 12-bit video processing delivers smooth grey scale to the 10bit(D) LCDs, while a built-in 3D LUT with preset or user-definable (via imported 3D LUTs) colour spaces allows for highly accurate colour visualisation in 2D or 3D modes.
Colour profiles are numerical models of colour spaces. It is usual for operating systems and programs to have a colour profile, as it allows them to interpret the colour in their colour space (Anderson & Krogh, 2011).
The software, which works under MS Windows 95/98/NT, displays a choice of colour spaces or reflectance curves, allows input and selection of reference values, will average multiple measurement and includes a verbal indication of colour differences.
In order to adapt as much as possible to the way in which the human eye perceives colours, the so-called perceptual colour spaces were developed (Uniform Chromacity Scale Spaces, these try to describe colour information in the most similar way that human perception does.
The world of colour is focused by Thompson by the metaphorical tool of 'colour spaces' (on which more below).
Drawing on experiences from recently released movies and TV projects, the masterclasses will look at questions of moving between colour spaces and show the latest colour science and grading tools in action.
Saonchez-Peorez, "Detecting skin in face recognition systems: a colour spaces study," Digital Signal Processing, vol.
Two uniform colour spaces CIELAB and CIELUV were simultaneously adopted by CIE to approximate human vision.