I find the main reason for the sharpest
tracks is to run traces between pins.
All other traces should be made as
wide as possible to minimize the
possible problems is gaps or
smearing of traces.
To go between pins you usually need 10 or 12 mil
traces. I have no problem doing them
by laser printing or copying pcb images onto
plain paper, ironing onto standard copper
clad boards, soaking the paper off, and then
etching in a warm bath.
Here is how I do it.
Note that it is extremely important to coat the
boards after etching with something (floor wax!)
that keeps them from oxidizing and allows good
solder flow.
Ciao,
Dave
The Inexpesive Seismometer Project