The other day I watched a 1966 Doctor Who story called The Ark. It’s easy to look at a TV show that old and laugh at the stilted acting, rubber monsters and crude effects. But given the archaic and draconian conditions the series was made under back then, I can only admire the creativity displayed by the director and his team in visualising a script which was scarcely less demanding than a contemporary Who story.

In the sixties, each Doctor Who episode was recorded virtually as live on a Friday evening, following a week of rehearsals. BBC rules strictly limited the number of times the crew could stop taping during the 90 minute recording session, which was to produce a 22 minute episode. Five cameras would glide around the tightly-packed sets in a carefully choroegraphed dance, with the vision mixer cutting between them in real-time as per the director’s shooting script. (Interesting side note: some of Terminator 2 was shot in a very similar fashion to maximise the number of angles captured in a day.) It’s no wonder that fluffed lines and camera wobbles occasionally marred the show, as there was rarely time for re-takes.

But what’s really hard for anyone with a basic knowledge of visual effects to get their head around today is that, until the Jon Pertwee era began in 1970, there was no chromakey (a.ka. blue- or green-screening) in Doctor Who. Just think about that for a moment: you have to make a science fiction programme without any electronic means of merging two images together, simple dissolves excepted.

So the pioneers behind those early years of Doctor Who had to be particularly creative when when they wanted to combine miniatures with live action. One of the ways they did this in The Ark was through forced perspective.

Forced perspective is an optical illusion, a trick of scale. We’ve all seen holiday photos where a friend or relative appears to be holding up the Eiffel Tower or the Leaning Tower of Pisa. The exact same technique can be used to put miniature spaceships into a full-scale live action scene.

In these frames from The Ark, two miniature landing craft are lowered into the background before the camera pans to a full-size craft in the foreground:

And in these later frames, another miniature craft is placed much closer to the camera than the Monoid (a.k.a. a man in a rubber suit). The miniature craft takes off, pulled up on a wire I presume – a feat which time, money and safety would have rendered impossible with the full-size prop:

Of course, Doctor Who was not by any means the first show to use forced perspective, nor was it the last. This nineties documentary provides a fascinating look at the forced perspective work in the Christopher Guest remake of Attack of the 50 Ft. Woman, and other films…

And Peter Jackson famously re-invented forced perspective cinematography for the Lord of the Rings trilogy, when his VFX team figured out a way to maintain the illusion during camera moves, by sliding one of the actors around on a motion control platform…

So remember to consider all your options, even the oldest tricks in the book, when you’re planning the VFX for your next movie.