Homebrew PCBs

I use an Epson R280 inkjet with Jetstar Premium and some custom driver
software, and get "nearly perfect" black films out of it.  You have to
use the custom driver so that you have control over every ink drop,
though, as normal software doesn't know about the ultra-fast trying and
tends to "dither" the ink, which IMHO ruins the films.  A larger number
of smaller drops, with a more regular pattern, leads to better films.

One thing I do, though, is clean the heads before every print, then do a
test print on plain paper (same driver, different settings, same ink
drops but fewer of them) to verify the head is clean.  Dirty heads tend
to place the drops more randomly off-center.