A light beam projector has a light source and a reflector arranged to have light generated by the light source converge into a light beam. The reflector has a hollow curved surface with a focal point where the light source is positioned, and a filter able to change the color of the light beam based on the angle of incidence of the beam on the filter. The filter has a plurality of filter elements arranged by sectors to form a diaphragm between the light source and the light beam outlet from the projector. In order to change the angle of incidence of the light beam on the filter elements, the sectors are able to rotate on their axes from a closed position, in which they fully intercept the light beam, to an open position, in which they do not intercept the light beam, as well as to all intermediate positions. The light beam projector has at least two filtering systems, one including at least one of the diaphragms, placed one after the other along the path of the light beam. Each sector forming the diaphragms can be rotated independently of the other sectors.