Optical system for creating colored fields of light and components therefor

An optical system for creating coloured fields of light from a source of essentially white light by the subtractive method, having an independent and continuous control of hue, saturation, and intensity, and comprising at least one set of coloured filters entering to a varying degree into the ray path, in which each set of filters consists of two filters moveable relatively towards and along each other in substantially parallel planes to obtain varying degrees of overlap, and in which the filters in each set have a comblike structure in the colouration and in that said structures are substantially aligned with the direction of movement, characterized in that at least one edge of each tooth of the comblike structure comprises a first edge portion at a first acute angle (p) to the direction of relative movement of the filters and a second edge portion at a second acute angle (s) to the direction of relative movement of the filters, and the first and second angles are not equal, such that the teeth of the comblike structure deviate from a simple isosceles triangular shape.