In a color camera, white balance is the process of adjusting the values of its color differences signals so that a white object in a scene illuminated by a particular source of illumination is displayed as a white or grey (i.e. no chrominance). The normal color reference illuminant has a color temperature of 3200 K, equivalent to a halogen lamp. The human eye is a subjective device, constantly readjusting its color balance according to the lighting context (our eye knows what must be seen as white). Unlike the human eye, a camera is an absolute measurement device, and its color balance has to be adjusted to suit the color temperature of the light illuminating the scene, for example sunlight is different from 3200 K. Several adjustment modes are available, fixed values (pre-adjusted), One-push, automatic tracking. See also One-push WB and ATW.