Epson p20000: banding/lines when printing solid black on matte

[noritsue_me]

Greetings,

Printer: epson p20000
paper: hahnemuhle Photo rag matt baryta

Issue: Whenever I print my photo, which is basically solid black except for a small white section, I see banding show up which is parallel with the direction of the print head. The nozzles are not clogged and my prints of more standard color photos on the same paper look totally normal.

I've tried messing around with the settings by adjusting the platen gap, paper thickness, and paper suction up and down to see if there's any change in the issue, however I have yet to see any signs that adjusting those settings is affecting the banding in any way.

When I print the same photo on a thinner matte paper (moab lasal 260), the same banding issue does not reoccur, however, a single band near the end of the print appears. This band appears to be a different "type" of band from the prints on the hahnemuhle paper, perhaps a different issue all together.

I'd greatly appreciate any insight as to what might be causing this issue.

[Lessbones]

If nozzles are all showing as clear, then you should try doing a feed adjustment.  I can't remember exactly where it's located, I think in the custom paper settings?  But I know it's there on that printer.  Otherwise you're gonna need to slow down as much as you possibly can and turn off "high speed" aka Bidirectional printing.  Solid blacks can be the hardest thing to print.