Akira has everything described in the article practiced to an absurd degree. I don't think there is a single light in the movie that isn't an actual real light.
https://www.youtube.com/watch?v=xf0WjeE6eyM
"AKIRA: How To Animate Light"
They may have been referring to the glow/bloom effect created by backlighting the cel, which actually is "real light" and is used very liberally in Akira.
Regardless, very cool video!!