From the invention of colour television to the advent of digital effects, CSO (or Chromakey if you worked for ITV) was the most prevalent special effect in the business. Subjects were photographed in front of a plain blue (or green) background, which was electronically replaced with a starfield, library footage of the Grand Canyon or a picture of Joe Gormley, according to taste. Limitations to this technique gave programmes of the era a distinctive look. The lighting had to be extremely bright, so the people in the foreground looked unnaturally washed-out compared to their background. Hair and shadows were the technician’s nightmare, adding a furry blue fringe around the subject if they weren’t careful – a sort of anti-Ready Brek glow. The result – every programme, from Blake’s 7 to The Kenny Everett Video Show to Nationwide, took on an eerie, fuzzy quality which just made telly all the more mysterious and imposing.