What produces this pattern in printing?
 

I'm curious as to what produces this "honeycomb" pattern?

The screening.

each color is a halftone, or picture made of dots like a single color newspaper picture. Only with four colors they work better if they're each at a different angle, so they end up with that sort of honeycomb pattern.

Sort of like pointillism, i.e.- Georges Seurat? Here are some zoom scans of a 78 Bartkowski I took last summer for another thread. Neat...