橋本 麦∿Baku Hashimoto

Extending the slit-scan technique

Once I said that there is still a bunch of applications when it comes to slit-scan in my interview. Thus I created this to prove it. It doesn’t look like slit-scan at a glance, though, I certainly used the technique.

It is often difficult to imagine a rendered image when you applied slit-scan to footage in some way. But I have a nice analogy to understand slit-scan. Imagine there’s a quite thick flipbook that all frames of a video are bound page by page. If you just rifle through it, the original video will be just played. Slit-scan intrinsically means slicing the flipbook diagonally.

In the top video, the flipbook of the car traversing right-to-left looks like below:

If you slice the flipbook like this, the car would shrink.

The cross-section doesn’t need to be planar. The only middle part of the car gets longer when you slice it in zigzags like this:

To create this effect in After Effects, S_TimeDisplace by GenArts was so useful since it can interpret b/w matte to map black pixel to the first frame of video and white pixel to the last frame. After Effects’ built-in Time Displacement effect only allows to time-remap each pixel relative to the current time.

Here is the additional screenshot to recreate the composition in AE:

I think the name of “slit-scan” makes people confused. It’s rather appropriate to call it “time displacement” just like the name of AE’s effect because this technique actually means displacing a cross-section of “world volume” (like a flipbook, it is an imaginary 3D cube consists of 2D image + 1D time) along with “time axis”. Part of time displacement whose cross-section is planar is so-called slit-scan. You can just use the technique to generate a still image. Or you can generate a video by shaving the world volume and slightly changing the position of cross-section frame by frame.

With this way of thinking, now you can imagine how to make it when you see something like slit-scan works. This very long panorama is that I generated using slit-scan from live footage shot from a train window between stations when I was a student. Though it looks like Adam Magyar.

It also interesting that orthographic projection in horizontal and perspective projection in vertical mixed up in a single image.

Video artists, Páraic Mc Gloughlin and Hiroshi Kondo who I like also made videos with time displacement.

I was also inspired by Dirk Koy’s this video a lot especially from the beginning part that a car shrinks weirdly. Slit-scan with a low FPS footage causes a jaggy image, yet he turned the artifact into an interesting visual.

Inception style drone photography which used to be in fashion several years ago is also a sort of time displacement. Though some tutorials teach to combine 4 or 5 images from different angles somehow with Photoshop.

I would like to experiment with time displacement as it still has a lot of possibilities.