Learn all about the Time Displacement filter, which creates an effect known as slit-scan, a trippy looking time manipulation that can be used to represent a time travel, a warp in the space time continuum, a drug trip and much more.
A few months ago, Eddy Bergman posted a tutorial Slit Scan or Time Displacement Effect Tutorial for his site After Effects Tutorials, on our After Effects Portal Facebook group. He used the Muse video, Unintended, as an example, which utilizes the slit-scan Photography technique. Now, I'm a HUGE fan of Muse and I had never seen this video. What can I say? It's trippy! The slit-scan effect is used throughout the video and applied to slow-mo footage.
Muse - Unintended
Slit-scan Photography has been around for years, but unless you've done it, you may not know exactly what it is. There's a really well known sequence in Stanley Kubrick's 2001: A Space Oddyssey that uses the slit-scan technique, and you've probably seen it but may have not known what it was called. (By the way, you can see the original images used in the 2001 slit scan sequence here.)
So, what is slit-scan photography? According to Wikipedia, using the traditional methods:
The slit-scan photography technique is a photographic and cinematographic process where a moveable slide, into which a slit has been cut, is inserted between the camera and the subject to be photographed.
With modern software, you're basically playing one portion of the frame faster than another portion so that footage and elements in the video are stretched, squeezed and twisted, based on movement. This effect really gives footage a strange, surreal look, which works well when filmmakers are trying to show another dimension, time travel, or an LSD trip.
So that you get a better feel about what can be done with this technique, here are a few samples.
Watch the video below to see a quick comparison of similar settings in After Effects Time Displacement, Boris Continuum Complete BCC Time Displacement and GenArts Sapphire S_TimeDisplace. I will be referring to these examples in the following descriptions.
Although it looks cool and complex, Time Displacement is a very simple effect to apply. It will definitely take some finessing. The effect consists of two parts: the footage layer and a gradient, which feeds luminance levels to the time displacement. Here's how you do it (and I'll assume that you know the basics of After Effects... you know, things like precomping, basic effects, etc.).
In grayscale images, the luminance value range extends from 0 to 255, and it’s converted to a scale ranging from -1 to 1. A luminance value of 0 produces maximum backward displacement, meaning that pixels at the current time are replaced by pixels from a previous time. A luminance value of 255 produces maximum positive displacement, meaning that pixels at the current time are replaced by pixels at a future time. A luminance value of 128 produces no displacement. For other values in grayscale displacement maps, you can calculate the displacement amount, in seconds, using the following equation:
Displacement amount in seconds = maximum_displacement_time * (2 * (luminance_value – 128) / 256)
In the Time Displacement effect, choose the gradient layer as your Time Displacement layer. You can place it below your footage and turn off the visibility for the gradient layer.
When you preview, you should now see the effect. This is where you'll want to tweak the values for Max Displacement Time [sec] and Time Resolution [fps]. You will also likely want to adjust your gradient.
Tip: Notice how the effect does not look as good in the video footage in the beginning of this section, but looks stellar on the text sample with the word "Toolfarm". The clean edges were achieved by cranking up Time Resolution to 150fps. The drawback to upping the value of Time Resolution is that there is a huge render hit.
The BCC Time Displacement works a lot like the AE plug-in but has several more bells and whistles and just gives a lot nicer of an effect on footage, in my opinion.
Why is it better than the one that ships with AE?
The third plug-in I'm covering is in the Sapphire package, and although GenArts normally hits them out of the park, I do not love this filter. It doesn't give as smooth of effect with footage as BCC Time Displacement or with text like the AE Time Displacement does. A frame blending option is needed in a big way. There's just a single preset and it's the default setting. It worked about the same as the AE Time Displacement filter does on footage, but didn't fare as well on text.
I could live with all of that but the killer was that it caused AE to crash on render, 6 times in a row. Sapphire is normally the Clydesdale of plug-ins so it surprises me that I could not get it to render. I ended up removing it from my sample above because I just couldn't get it output.
Posted by Michele Yamazaki
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