Abstract: A head up display may include a combiner having a semi-transparent mirror to reflect light projected by a head up display light source. A dimmable element may be disposed adjacent to the combiner and opposite the semi-transparent mirror. The dimmable element may be configured to reduce the transmission of light reflected by the combiner through the dimmable element. The dimmable element may include a control system configured to reduce the transmission of light reflected by the combiner according to a plurality of light transmission reduction steps and may include a feedback control system configured to adjust the transmission of light through the dimmable element based on at least a light sensor and a light source measuring light transmission through the dimmable element.