A white point is one of a number of reference illuminants used in colorimetry which serve to define the color "white". Depending on the application, different definitions of white are needed to give acceptable results. For example, photographs taken indoors may be lit by incandescent lights, which are relatively orange compared to daylight. Defining "white" as daylight will give unacceptable results when attempting to color-correct a photograph taken with incandescent lighting. Colorimetry is the science that describe colors in numbers, or provides a physical color match using a variety of measurement instruments, depending on the desired information about the color or colors the customer requires. ...

Each white point illuminant is ideally described as a spectral power distribution, that is, by giving the amount of power per unit wavelength at each wavelength of the visible spectrum. This will allow the coordinates of the white point in any color space to be defined. For example, one of the simplest white points to understand is the "E" or "Equal Energy" white point. Its spectral power distribution is flat, giving the same power per unit wavelength at any wavelength. In terms of the CIE XYZ color space its color coordinates are [K,K,K] where K is a constant, and its chromaticity coordinates are [x,y]=[1/3,1/3]. A color model is an abstract mathematical model describing the way colors can be represented as tuples of numbers, typically as three or four values or color components (e. ... In the study of the perception of color, one of the first mathematically defined color spaces was the CIE XYZ color space (also known as CIE 1931 color space), created by the International Commission on Illumination (CIE) in 1931. ...

A list of common white points, their CIE chromaticity coordinates (x,y) and their correlated color temperature (CCT) are given below. The CIE chromaticity coordinates are given for both the 2 degree field of view (1931) and the 10 degree field of view (1964). White light is commonly described by its color temperature. ...

White light is commonly described by its color temperature. ...

External links

CVRL Tabulated data- for illuminants A and D65 (click on "CIE Functions" menu choice)

A Review of RGB color spaces (BabelColor).

References

• Agoston, George A., Color Theory and Its Application in Art and Design, Springer-Verlag, New York, Revised Edition 1987. ISBN 0387170952

• Wyszecki, Günter and W.S. Stiles, Color Science -- Concepts and Methods, Quantitative Data and Formula (2nd edition), Wiley-Interscience. (July 28, 2000). ISBN 0471399183