The present invention provides a light source, method, computer-readable storage medium and computer program product for optimising one or more illumination characteristic thereof. In particular, the present invention provides a light source comprising four or more light-emitting elements, or groups or arrays thereof, each one of which having a respective predefined emission spectrum which, when combined in accordance with a given intensity ratio, provide illumination at a particular color temperature. This light source may comprise an internal and/or external selection module for selecting one or more illumination characteristics to be optimised, and internal and/or external computing module for optimising drive parameters of the light source to provide the optimised illumination characteristic selected. The light source may optionally be hardwired to operate according to predefined drive parameters selected, using a method, computer-readable storage medium and/or computer program product of the present invention, in order to optimise a pre-selected illumination characteristic.