I rebuilt my UV box with 9 rows of 12 leds covering an A4 area, I had to
use a diffuser in the end otherwise because of the fairly wide spacing
the led mounting was too critical to get a good even spread (even with
the leds 15cm away from the artwork).
Anyway, I wanted to dial in the numbers a bit particularly because of
the diffuser I was concerned that the resolution wouldn't be there
(turns out, nothing to worry about, 8/8 seems just fine, I'm never going
to want less than that).
I couldn't find a simple small test pattern in a usable (gerber) format,
so I made my own, perhaps somebody might find it useful also one day.
Lines from 8 to 18mil, separations from 8 to 16mil, holes 0.8mm and
1.1mm with 0.2mm, 0.35mm and 0.5mm rings, 1206,0806,0603 and 0402 pads,
and a minimelf for no particular reason.
All repeated 5 times for a stepped exposure to home in on the right time
(which turned out to be around 3m30s, but there is a massive amount of
leeway, probably a minute either side is usable).
Anyway, here it is on github, gerber and pdf
https://github.com/sleemanj/pcb-test-patternyou can use the Download Zip button on the right side of the page if you
just want the files and not mess with git.