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Making an Escherian staircase

Everyone has seen M. C. Escher’s famous lithograph Ascending and Descending of the perpetually ascending and descending staircase. Of course, we all know that this is an optical illusion and that such a thing could not be made in real life.

Or could it?

Take a look at this.

Of course, this has to be a trick and Snopes says that it was the project of a graduate student at the Rochester Institute of Technology aimed at creating an internet myth. It is done with mirrors and tricky camera angles and editing.

I don’t know exactly how it was done but you can see it involves some trickery by looking closely at the boy’s left arm in the following video.

Still, it is pretty ingenious.

Comments

  1. Jeffrey Johnson says

    They must have two cameras, one on each floor. The upstairs camera films the right side of the screen, and the downstairs camera films the left side of the screen. Then the two videos are edited together vertically. The boy’s left arm “materializing” out of the wall seems to confirm that there is a boundary between two different videos at that point in the image.

  2. StevoR : Free West Papua, free Tibet, let the Chagossians return! says

    Wow. Neat idea. Well done. Thanks Mano Singham. :-)

  3. Trebuchet says

    More than one trick going on here, I think. The guy at the beginning may be a set of identical twins. But there’s clearly some video trickery going on with the young boy emerging from the wall.

  4. Mano Singham says

    I have sent a message to reader kyoseki who works with special effects to see if he can give a clear explanation of what might have been done.

  5. kyoseki says

    The video is actually pretty well done, they’ve kept the scope of things nice and simple so they can execute them well. The compression and resolution tend to obscure some of the tell tale signs of image manipulation, but this is what I think they did;

    The easiest shots to explain are the ones with a nodal camera – these are the shots where the camera’s position doesn’t change, just it’s orientation, so the initial shot of the white guy ascending the staircase and the later “interview” shots with the kids running up and down in the background.

    The way the initial shot (0:10-0:31) was accomplished was by simply shooting footage of the nerdy white guy giving the introduction and ascending from the current floor to the floor above (call this the “A roll”) and footage of the same guy climbing from the floor below (call this the “B roll”), then in editing, they simply play the A roll on the left hand side of the plate and the B roll on the right, using the generally featureless central column of the staircase as a divider.

    The tilt up/down of the camera was likely accomplished either by using a motion control rig to control the camera’s motion and make sure the A roll motion matches the B roll motion (unlikely, these things are expensive and would require the guy to EXACTLY choreograph his timing to that of the camera) or, more likely, they shot a wider plate and simply cropped in and panned in 2d during editing.

    In this particular case, they’ve just used a straight line to separate the plates, as evidenced by the kid’s disappearing arm in the second video, a more elegant solution would have been to use rotocoping (manually tracing) or keying (pulling a matte using color/brightness trickery a la the local weather guy) to let them put the kid’s arm into the A side of the plate.

    Note that this technique is used a LOT in tv/movies where you have a single actor playing twins or clones or whatever, the hallmarks are usually a locked off (completely static) or nodal (stationary but pivoting) camera and some means of hiding the blend between the A side and the B side – there’s a shot in “The Island” that comes to mind where there’s two Ewan McGregors interacting and they’ve used a giant bottle of Michelob Light to hide the transition, which gives them an easier FX shot – http://www.yourprops.com/movieprops/default/yp_5134d815cbf644.65107574/The-Island-Michelob-Light-Aluminum-Bottle-2.jpg (I think the actual shot is a little bit further on, since the bottle crosses his entire forearm in the relevant shot).

    It’s usually easiest to fade from A roll to B roll across a largely featureless surface, particularly one that stretches from the bottom of frame to the top, because it lets you blend the left and right side together to smooth out any slight differences in camera motion, other techniques are to have some kind of foreground object obscuring the join (as in The Island) or to use whip pans (a fast pan from left to right or right to left) or crash zooms (sudden zooms in or out) because the motion blur lets you get away with murder.

    The hand held shots where the camera is following someone in the stairwell are a bit trickier.

    I suspect that the water shot (1:51-2:08) just uses a second girl who looks sufficiently like the main one (think stunt double), she’s down the far end of the stairwell at the end of the shot and we never get a particularly good look at her – he occludes the central column pretty well and I don’t think they have a decent roto guy so my guess is that there’s no digital effects in this shot.

    The remaining two shots, where we follow someone through the stairwell and meet the same person at the beginning and end of the shots are a bit trickier to explain. There is a whip pan at 1:27 that could be used to transition from one roll to another, similarly when the camera transitions across the central column at 1:33 that could well be another transition to a third piece of footage of the same girl doing a reaction shot from upstairs (any time the camera whips across that largely featureless central column, I’m assuming something nefarious is going on) – but it doesn’t really account for the nerdy white guy’s presence on both floors.

    Note, however, that she takes a lot of time climbing the stairs and the camera is very close to her, blocking our view of the upper floor for a large part of the shot – my guess here is that as soon as he is out of frame, nerdy white guy takes another route up to the floor above – someone running an elevator with a fireman’s key would be a reasonable guess there.

    A similar mechanic was probably used for the black guy at the end – note that we also don’t see him for most of the shot, although again, at 3:14, there’s a very suspiciously blank frame where we don’t see the connectivity of the arm through the shot, so it’s entirely possible that’s the transition from A roll to B roll and no physical gimmicks were involved, again, it’s difficult to tell with an internet video because of compression artifacting.

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