Doctor Who has historically used practical effects to a much greater degree than many other science fiction shows. For instance, much of the backgrounds on the opening titles until the 18th season are practical, because they were achieved by pointing a camera at a monitor and filming the results (a few of them, however, had several elements filmed in separate passes - The most practical of all opening titles sequences of the series were in fact the slit-scan versions used in 1973-74 and 1974-80). Most monsters seen on the original series are also practical, because they were filmed alongside the actors in a given scene. A number of the video screens seen in the show are practical, in that the film on the screen was actually being played back on the screen as the actors in the foreground lo