Archive of the former Yahoo!Groups mailing list: Homebrew PCBs

The R320 is limited to 1440 DPI (well, 5760x1440 but square pixels are
nice) but that's probably still more resolution than needed for what we
can home-brew. The R280 can do 5760x2880. Anyway, if your existing
print software can be told to print at 1440 dpi, and your EDA software
can produce a print of that resolution, you should be all set. The
interesting factor will be if the print software can be told to put down
more ink than normal (choose ultra glossy film if you have a choice).
My software uses the smallest drop size but 100% coverage (no dithering
or halftones).

An unrelated thing you might think about is how you're holding the film
against the PCB. I only get good results if I (1) print the film in
reverse, so that the inked side is against the PCB, and (2) use a vacuum
to hold the film tight against the pcb (gravity won't work).

With a decent film (jetstar, silkjet, etc), high enough resolution, and
enough ink, you should be getting jet black prints with crisp edges.
With something to hold the inked side tight against the PCB, you should
be getting crisp edges on your etch resist too.