It's neat that the artist is actually taking a photograph of a projected video, but if you accept digital processing and are only after the visual effect of this, averaging video frames is a lot easier (though less precious).
The artist Jason Salavon has done very similar things (20 years ago):
Not an artist myself, but it reminds me that maybe ten years ago or so I produced a series of "movie abstracts" which were whole movies accelerated to last 10-15 seconds by temporally averaging frames (the tmix ffmpeg filter).
I don't think I have them anymore, it was just for showing to friends. But the result was interesting, especially for some Wong Kar-Wai movies or, as I remember, Hero, where colours play an important role.
The artist Jason Salavon has done very similar things (20 years ago):
http://salavon.com/work/SpecialMoments/
http://salavon.com/work/LateNightTriad/
http://salavon.com/work/Homes/
http://salavon.com/work/EveryPlayboyCenterfoldDecades/
I don't think I have them anymore, it was just for showing to friends. But the result was interesting, especially for some Wong Kar-Wai movies or, as I remember, Hero, where colours play an important role.