CIE XYZ spectrum

Description

../../../_images/ciexyz.png

CIE XYZ spectrum with x=0.2386, y=0.2303, Y=180

Spectrum This spectrum type generates a metamer spectrum from CIE 1931 XYZ color coordinates. For convenience, it also accepts other color spaces derived from this one, such as sRGB or xyY.

The generated spectrum has the following properties:

  • Exact matching of XYZ values with CIE 1931 2° observer.
  • Natural smooth and continuous spectrum with no discontinuities or sharp peaks
  • There is no guarantee on the maximum value taken by the spectra, and especially, it is not bound to [0,1] as the RGB spectrum. Therefore, it may not be suitable for use as an albedo or reflection coefficient.
  • The spectrum continuously dependent of color coordinates.

Unit

This spectrum type is photometric. For instance, when used as the base spectrum of an emitter, the Y coordinate correspond to cd/m² values.

Parameters

name type description
rgb color The color coordinates
gamma real The gamma value

Ocean XML 3.0 example

<spectrum type="cie-xyz" name="base" xyz="0.2386 0.2303 180 xyY"/>