good & bad news :)
The bad news: the laser printer cannot handle large black prints, some unit of the printer makes a random glossy layer on it.
the random gloss
the (very) good news id that the luminance correction is not very angle-dependant, means that except for that random gloss, the correction works at a wide variety of viewpoints, that’s really nice.
from the left side, the gloss dissappears and the flat is still “flat.”
below: zooms on different parts from the left side (same shutter speed)