Homebrew PCBs

"calvingrier" <cgrier@...> writes:
> > laser printer is 600dpi or 1.33 mil per pixel, so I use multiples
> > of that to get consistent results.  The limitation with my printer
> > is its ability to place the toner particles precisely.
> 
> 8.33mil? is that a multiple of 1.33? ;-)

Sigh, wrong math, right results.  1/600 is 1.666 mil, not 1.333 mil,
resulting in possible trace widths of:

Pixels   Width (mils)
------   -----
0        0.000
1        1.666
2        3.333
3        5.000
4        6.667
5        8.333
6       10.000
7       11.667
8       13.333

Traces of other widths will be printed as either the next smaller or
next larger size, depending on your rasterizer.  Same with the space
between traces.  So you could be off by as much as 0.833 mil (half a
pixel).

Switching to a 2880 DPI inkjet lets me choose any size and get within
0.2 mil of the right size.