Saturday, March 23, 2013

Slit scan photography

Nevsky prospect, autumn 2012.

Take a look at the unusual photo above. It seems distorted: people have normal sizes, while cars are squashed into vertical strikes. However, it shows the reality as is, but under unusual angle. Time and space coordinates (strictly speaking, horizontal coordinate) were interchanged in this image. See the video below:

Demonstration video

The whole image (click image to zoom)

"The road of time".

Interesting features of slit-scan photos

  1. All people and cars are facing to the right.Because they are facing pastwards. When a man walks, his or her nose comes first, and the back of the head comes last. Thus, in a slit-scan photo nose is always on the right (right is past, left is future).
  2. The faster object moves, the shorter it seems.
    Obviously, horizontal length is a time, object spent crossing the slit. It is why fast cars are squashed into pancake-like objects.
  3. Background turns into horizontal bands.
    Every still object is either invisible, or shows up as an uniform color band.

More photos

Here are few more photos, made by me. Also, see the whole gallery.

Tugboat, pulling a barge. It is interesting to see, how waves on water are forming time pattern.

Tugboat pulling a barge.

Ducks on a surface of the Moika river. Red background is a granite pavement.


Just a crossroad.

Waves on a shallow water.

Raindrops. In slit-scan photos, raindrops are producing hyperbolas rather than circles.

People, moving toward the camera (camera was pointing along the Nevsky prospect). Step movement causes ripples in silhouettes. Click to zoom.

Similar photo,more crowded:

One more crossroad, long exposition (very wide image).

Horizontal slit

In the photos above, slit was placed vertically. Placing it horizontally can produce interesting effects too:

Nevsky, horizontal slit photo. People, cars, reflection in a billboard.

Here, vertical coordinate of the picture corresponds horizontal coordinate of the original video. All horizontally moving objects are becoming a slant strips; fast objects are almost vertical, still objects are horizontal.

Horizontal slit + camera along road (image rotated according to slit orientation):

People are coming - horizontal scan.

Another sample. Some people are changing their speed, drawing curved trails:


Making scit-scan photos

My own tool that makes slit-scan photos converts videos to, on Github: slit-scan. It compiles only under Linux and requires FFMPEG and ImageMagic.

Making demonstration video

Simple script, written in Python 2, source is on github gist.