On 2007-04-07, RST Engineering wrote:

(Please don't tell me to buy color coded bags. It is hard enough to find
exactly the right size for a job without specifying color too.)

You could sew colored flags on...

Anyway, I just want to stencil a contents label on the outside of the bag
with plain old white paint

There's an instructable on screen printing:

http://www.instructables.com/id/EFAN6S16FTEQ2W3MOV/

the process is a lot like making a photo etch pcb. You use some goo on
some gauzy fabric which you expose with a transparency to harden the
areas where the ink won't go. Then rinse out the unexposed goo and you
have a screen.

--
Ben Jackson AD7GD

http://www.ben.com/