I use black and love it— but only with 120 line lengths. The default of 80 is wayyy to low for the days of 4k monitors. The tricks it uses to split some things up onto new lines actually makes it less readable.
I agree 80 is too low, but it doesn't have anything to do with 4k monitors, it's just that 80 is too short. Any longer than 120 is not readable imo. Luckily Black lets you change the line length so it's not an issue.
Maybe it’s different for other people but smaller text is much easier on my eyes with a 4k monitor.
As long as you can easily review code side-by-side with line numbers intact, you're good. The default was chosen for lower resolution 13" laptop monitors to be able to display the Phabricator diff page (think: Github PR review page) without having to wrap any lines.
I agree. I've sometimes found Black's output to be on the borderline of unreadable with the default line length of 80. My team settled on a length of 120 (the only Black config item we changed) and it has largely, though not entirely, solved that problem.