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

I just did a quick test with my UV LEDs using a step pattern going
from 10/10 spacing down to 1/1 spacing in thousands of an inch. This
test pattern was printed by an Epson 2400 printer using Pictorico
transparency.

The leds were 1 1/4 inches above the board with a .5 inch spacing. I
tested with 4 LED's running 2 in series and then 2 of those in
parallel running 20ma at 6.6V.
Exposure time was 60 seconds.

After developing in sodium carbonate, I got good lines down to 3/3
spacing. The 2/2 looked pretty good as well, but was a bit jagged.
Possibly due to the 1440 dpi resolution of the printer. The 1/1 lines
were all merged together.

I will try 3/4 inch and 1 inch spacing over the weekend to see how
those work, before I commit to a spacing. I will post the results of
those tests as well.