It was in 1935 that the forerunner of today's systems of colour photography first appeared on the market in the form of ‘Kodachrome’ film. This, and other subtractive systems, quickly replaced the earlier additive methods and remain the accepted practice today. The intervening period of nearly 50 years has been one of intense research and improvements have been made in virtually every aspect of the systems. The cyan, magenta and yellow imaging dyes have been improved in their spectral absorption properties, in their light fastness and in their stability to long‐term storage in the dark. The photographic speed of the systems has been increased and the graininess reduced, by better emulsion‐making and coating techniques and by the use of better developers and dye‐forming couplers. The sharpness of the systems has been improved by the use of thinner layers and special additives to control the spatial properties of the images. Very short access times have been made available by special systems that provide automatic processing immediately after ejection from the cameras. Colour television has been developed mainly over the past 25 years and, unlike photography, continues to use additive, rather than subtractive display devices. This is because the photographic disadvantages of additive display (limited resolution and absorption of light) do not apply in television. Recent years have seen attempts to apply television principles to traditionally photographic markets such as amateur photography, by the use of electronic cameras. The electronic systems have the advantage of re usable recording media, but the photographic systems have the advantages of much less costly cameras and higher resolution. Combined film‐electronic systems are likely to provide the highest technological performance in