grantfair2001 wrote:
>
> By positive, I mean that the copper tracks will appear white when
> printed on paper, and etched portions will be black. My PCB software
> does the usual "negative" print - copper tracks are black, etched
> areas white, but not the positive print.
>
As someone already pointed out, you have your terminology reversed by
trying to label it what you want it to do. On screen is a positive,
what you're describing is a negative, and then the exposure process
negates it again to make a positive PCB with correct tracks. Note that
your reversed terminology will make you want a 'positive' and when you
print a 'positive' it'll be backwards to what you want. What you really
need to find is the program's way to print a negative image.
Keep in mind that you can always reverse the sense of positive and
negative in anything, electronic or mechanical or photo or anything
else, and it'll still work logically as long as you keep the senses
consistent. That means you are REQUIRED to correctly determine and
match the normal conventions, or you will be thinking the wrong thing
and be getting results that you think don't work correctly when really
you just chose the wrong result by being backward to normal polarity.
It's not that the program's 'positive' output or 'negative' output
aren't correct. You just chose their 'positive' when you really wanted
their 'negative' and have your choices reversed to the conventional
direction..
Alan