There is provided a lighting system for illuminating a space, the lighting system comprising: at least one light source; and at least one controller configured to: receive an indication of a pre-selected duration of an emission period for which the at least one light source is to emit light; control the at least one light source to emit light for the duration of the emission period, select a first spectrum in dependence on the duration of the emission period, and control the at least one light source to emit the light with the first spectrum during at least part of the emission period. There is also provided a display apparatus, a method and a computer program product.