A computer program, written by Symon Hamer and called "Tinter"¨ runs on PCs under Microsoft Windows 3.1 and 95. It provides for more subtle adjustment of shading than is normally possible, and it allows the user to see the effect of the adjustment when applications are in use.
The colour optimal for computer use is likely to differ from that optimal in overlays (which provide a surface colour) and in lenses (which provide for a change similar to a change in the colour of lighting). It is known that overlays and lenses have different optimal colours. Computer displays are usually self-luminous and can resemble a surface or a light source, depending on lighting conditions.