White point

The white point is generally defined as--or assumed to be--equal energy white (illuminant E). This is defined as [x, y] = (1/3, 1/3) in CIE xyY, and as [X, Y, Z] = (1, 1, 1) in XYZ color space. However, other white points may be used, generally defined by "white" standard illuminants or a color temperature