We have investigated the darkness induction of surround fields of various composition on a centrally located test field. Darkness induction can be described as a linear subtraction of the luminance of the induction region from the test field luminance, weighted for the size, the length of immediate contact and the distance of the induction field from the test field. Furthermore, closer induction fields exert a shunting effect on the induction effect of fields which are more distally located on the same radius, and neighbouring fields mutually interact. A model is discussed which takes into account these variables. It is compared with older models as well as with the Retinex-model as formulated by Land (1983). Our data and model are closer to the model of Jameson and Hurvich (1964). Neurophysiological correlates and mechanisms are discussed.