Rough areas in my 1st layer

[DeltaCon]

I am having this issue where smaller areas in a large first layer seem to be very rough, while other areas look really great. When the second layer goes over the rough areas, most of the roughness disappears under the second layer and is not visible anymore. Adhesion of the first (and second) layer is great, so that is no problem, I was just curious about the why of these rough spots.

I am printing this first layer without bed leveling, but of course with duet auto calibration. Detail is so fine that you can see a moiré pattern I am using ABS at a temp of 220C, and a layer height of .2mm the bed is 90 (my PEI did not adhere great at 80, but at 90 it does.

Anyone an idea?

[DerStig]

Those look like high spots on the build surface making the nozzle closer to the build plate

[DeltaCon]

Those look like high spots on the build surface making the nozzle closer to the build plate

Thought about that, but would the border between rough and smooth not be smeared over a longer distance? I' try rotating the bed to see if the pattern follows.