Apparatus for obtaining a desired tint

Apparatus for obtaining a desired tint having a given hue and a given saturation, comprising light colouring means having, at least, a first region of a first colour, a second region of a second colour adjacent to the first region, and a third region adjacent to both the first and second regions, a light source to direct light towards the colouring means, an aperture defining a selected region of the colouring means which affects the light which creates the desired tint, and first and second movement control means to effect relative movement between the said aperture and the said colouring means, wherein the colouring means form a hollow cylinder with the light source being positioned therewithin, wherein the third region is a generally neutral region as regards colour, wherein the regions of respective different colour extend around the longitudinal axis of the hollow cylinder with the neutral region also extending around the hollow cylinder and being adjacent to but axially displaced from the regions of respective different colour, and wherein the said first movement control means are operable to effect relative rotation of the hollow cylinder about the longitudinal axis thereof to effect a change in the hue of the tint without changing the saturation thereof, and the said second movement control means are operable to effect relative axial movement of the cylinder to effect a change in the saturation in the tint without changing the hue thereof.