This is how forced perspective works, the trick of cinema that has remained intact for a hundred years

An earlier version of this article was published in 2016.

Suddenly the world can fold into itself as we see in Source thanks to advances in digital post-production. The technology of motion capture also allows creatures like those of Avatar reflect the gestures of the actors, looking very much like beings more real. Thanks to science, cinema is even more magical and that is why we can enjoy a truthful representation of the hobbits in The Lord of the rings or Hagrid in the Harry Potter universe.

But wait, are we sure that the latter is so? Actually, anything that involves changes in the size of the characters should make us suspicious. We were still in celluloid times when we saw the giant of Attack of the 50 foot woman. Even in the 90’s, in Darling, I shrunk the kids, walked a colossal baby through the streets of a North American suburb ignoring the digital effects that were not yet fully established in the industry.

No: the forced perspective it is an optical illusion as beloved in the world of photography as it is in the architectural and cinematographic world. Probably the most beautiful thing about this technique is that it does not matter how far digital editing technologies have advanced or how much budget you have for your film. If you want to reflect this effect, you only need a few good sets, understand what are the right lenses to film it and a little creativity on your part.

The forced perspective was used in its beginnings mainly to fantastic and low budget cinema movies. Series B launched titles like the aforementioned Attack of the 50 foot woman The King Kong. The trick of creating absurdly large or small creatures was very appealing to audiences and required hardly any preparation. In its most rudimentary form, forced perspective can be done using a frontal plane with a surface on which the actors can be positioned at widely spaced points.

In the film Princess Nicotine, from 1909, which we have in the video above, we see the actor close to the camera and the actress, small in size, dancing for the man on the table. The actress will actually be to the other side of the room, and the filmmakers only had to be careful not to move the camera and to reinforce the lighting so that both characters had the same luminosity. This trick may sound like you have seen it (or even made it yourself) … in the tower of Pisa.

The key: the Ames room

But the true revolution of this technique came from the hand of the Ames room. As we have pointed out, a crucial factor for the shots are scenarios that allow us to integrate that difference in size in the same shot without us noticing. So, in 1947, the ophthalmologist Adelbert Ames created the Holy Grail of forced perspective.

These rooms seem normal, cubic. However, this is a visual perspective trick since in reality the room it is built in a trapezoidal shape– The walls are sloped like the floor and ceiling, and the right corner is closer to the front viewer than the left corner (or vice versa). So, while the camera shows you a perfectly normal room, to one side you have a person who appears to measure 4 meters and on the other someone who would not be allowed to pass at most fairground attractions.

This effect is better understood in this video:

And yes, the people of the time pirate had fun playing with this for a long time:


As we have seen, the Ames room was initially limited to a single space. After understanding the architecture that promoted this idea, they stopped making rooms to make more elaborate scenarios. And that’s where Peter Jackson comes in and The Lord of the rings. To keep hobbits and dwarves on the same plane with larger creatures, he had to constantly play with perspectives.

The great contribution of the Jackson saga (in addition, of course, to help start a new model of leisure consumption in which the geek is the king and to leave for posterity the image of Orlando Bloom in a blonde wig) was perspective forced in motion. Something that had hardly been developed until now, due to its complexity, but that the high budget and the desire to experiment of the New Line Cinema production was taken very seriously.

For that, what Peter Jackson organized are scenarios with Ames effect … double. That is, rooms with mechanical mechanisms that moved at the same time as the camera, which also changed its focus, synchronizing with the physical movement device. In this way, the forced perspective continued to look correct on camera, but the film did not lose fluidity in each shot in which two people of different stature had to be filmed.

Although Jackson sometimes he also cheated. Not everything that was seen had been shot in the same take, and sometimes it used two sets. One for normal people and another with all the giant objects. Then I would put it all together with digital editing. The rest of the time, he applied the oldest trick in the world, even older than forced perspective: when Gandalf spoke, in the reverse shot the rear of Frodo that we saw was not Elijah Wood, it was someone short dressed as Frodo. A short person in a wig.

Sometimes, when we are very involved in the film, we can forget that the magic of the cinema is, sometimes, something of the most basic.


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This is how forced perspective works, the trick of cinema that has remained intact for a hundred years