Concept and creative process
Because the lead actor Jon Pertwee left the show after one season, I had to make a version with Tom Baker that same year with a minimal budget. I used the 'Slitscan' technique that had been developed by Special Effects Designer Doug Trumbull for Director Stanley Kubrick's iconic 1968 sc-fi movie '2001'. Trumbull had generously written an article, explaining the process in detail. The computer-controlled rostrum camera exposed one single frame at a time while tracking back up its column and filming a back-lit outline version of the shape (the slit) with which the tunnel effect was to be generated, such as a circle, a diamond or even the shape of something or someone. This was repeated for every frame, with the artwork behind the slit moving incrementally on each frame to generate the moving tunnel with the desired shape. In this sequence a circular slit made a circular tunnel, an outline slit of the Police telephone box made a Tardis-shaped tunnel and a diamond slit created a diamond-shaped tunnel for the new logo at the end of the sequence. Each frame took about 30 seconds to expose. Whereas Trumbull had a huge studio to give him a great length of scan, I could only use the 5 feet or 150 centimetres that the rostrum camera could track up its column.