"Eco Clean" wrote

| If you haven't tried Rasterbator, you really should. It's very easy.
|

And that worked fine? Then how about this:
Glue the results directly to the sign with spray
adhesive. Then cover it with sheets of adhesive
plastic laminating sheets.
Not exactly slick looking, but neither will be
ythe spray painting.

| When you mentioned the DPI, it confused me because it didn't have any
| effect on the output so I gave up on even looking at the DPI.
|

It gets complicated. If you have a 300-pixel-
wide image and print at 300 dpi, the result will
be 1" wide. But if you're using software and telling
it to print the size of the page, the software will
be resizing the image before sending it to the
printer. As Jonathan pointed out, that will probably
make for inferior results at some point, depending
on how big you made the original font. In other
words, a 12pt A enlarged to 200pt is probably going
to have very rough anti-aliasing. But if you used
a 200pt letter in the first place then it's not
being enlarged as a raster image.

At any rate, if it works and it prints the way
you want it then you may as well forget about
dpi for now.

| The task now is creating spray-painting templates with standard home
tools.
| Any suggestions?

Spray paint cans? It sounds like a hard job to
do well. Dripping. Overspray under the template.
And that's after the tricky task of cutting out
the letters.....
That's why I suggested stick-on letters or
gluing the printed sheet down directly.