1. A method for producing an anaglyph, the method including the steps of: producing a first digital image colour record representing a first image of a stereo pair of images; producing a second digital image colour record representing a second image of said stereo pair of images; each digital image colour record including a series of colour numbers representing the colours respectively of an array of visible individual coloured pixels into which the respective image is divided; said first digital image colour record having at least two colour numbers for each pixel of the first image, said two colour numbers representing the proportions respectively of first and second image colours in the colour of the respective pixel; said second digital image colour record having at least one colour number for each pixel of the second image, said one colour number representing the proportion of a third image colour in the colour of the respective pixel; combining said first digital image colour record with said second digital image colour record, to produce a single anaglyph digital colour record, by mathematically processing the colour numbers of the first and second image records respectively in a manner to derive a third series of colour numbers, said third series of colour numbers constituting said single anaglyph digital colour record and representing the colours respectively of an array of visible individual coloured pixels defining an anaglyph; said single anaglyph digital colour record having at least three colour numbers for each pixel of the anaglyph, said three colour numbers representing the proportions respectively of first, second and third anaglyph colours in the colour of the respective pixel.