I know the video, looks a good candidate for my Inkjet printer where then to put ascorbic acid in the printer cartridge
Pre coating the paper to make it alkaline, then coat with copper-sulfate and probably while still moist print on the ascorbic acid image.
I think it reacts to UV and Blue light in moist conditions, so probably cover it with plastic wrap during exposure.
That's pretty eccentric, indeed. Although not unique; I've seen pretty much the same approach being adopted for applying solder mask to a home-made PCB:
Which, frankly I find a rather messy approach, so I always use a rubber roller to apply it. Solder mask that is, not svinotype. I had never heard of that one!