Due a blog which I read regulary, I visited a nice site (in japanese) where they kind of develope a few special animated .gif files. I thought it may
interest a couple of members on BTS/ATS, which is worth to share:
I don't know if I am understanding it right, but I think they using a light pen or something similar.
another nice one...
The full Gallery and a video of an workshop which the author of the japanese/english blog visited can you find right over here: Pikapika