Baku Hashimoto

橋本 麦

Extending the slit-scan technique

Once I said that there is still a bunch of application when it comes to slit-scan in my interview. Thus I created this to prove it. Though it doesn’t look like slit-scan, 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 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’s the additional screenshot for your information)

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 of 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 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 possibility.