The invention describes a method for operation of a mercury vapour discharge lamp (1) in an image rendering system (30), wherein during a total operation time necessary for the presentation of an image content (C), the lamp (1) is deliberately operated in a saturated operating regime at least over a part of the total operation time according to a brightness parameter (BP) of the content (C), in which saturated operating regime mercury is condensed in an arc tube (2) of the lamp (1), and, at least over another part of the operation time, the lamp (1) is driven in an unsaturated operating regime, in which essentially the entire mercury evaporates. Thereby, the duration of the operation periods in the saturated and the unsaturated operation regime are chosen so that no significant blackening of the walls of the arc tube (2) arises during the total operation time of the lamp. The invention describes further an appropriate operation controller (27) for operation of a mercury vapour discharge lamp in an image rendering system (30) according to this method. Moreover a method for driving such an image rendering system and an appropriate image rendering system are described.