Re: gEDA-user: pcbexpress.com and ``pcb'' ``negative'' solder mask layers

["harry eaton" <bumpelo@xxxxxxxxxxx>]

> > > Do you mean that you have changed polarity of something in PCB while
> > > changing version?
> >
> > I don't know about the "while changing version" part, but yes, we
> > changed the polarity of the mask gerbers a while back.  4pcb
> > complained about it and helped us get them right.
>
> This must have broken my whole Ronja project.
> The README assumes the polarity is consistent across versions of PCB.
> So it's dependent on PCB version now?

Sadly, there really isn't an industry wide standard for the gerber
polarities,
some vendors want positives, most want negatives for the masks It is obvious
from the files what polarity they are and no reasonable PCB manufacturer
would build the board wrong. Worst case they would simply hold the job
if they don't know how to invert the polarity.

> Is it possible to make PCB print from commandline or add some PCB
> commandline flags to select the polarity or to store the polarity setup
> inside the PCB file?

That still wouldn't help you because we don't allow for per-file polarity
control.

>
> Or make separate program based on existing PCB code that converts .pcb
> into Gerbers and postscript?

This is always possible, someone just needs to write it.

>
> If someone installs new PCB version, generates the files and sends them
> for manufacture (best in 200-piece series as ronjashop.com does), a
> mailbomb will arrive to me by mail...

I don't see why. In principle the manufacturer would either build the boards
just
like you expect or hold the job complaining about "I want the other
polarity".
Even when you explicitly misinform them about the file polarity I think no
manufacturer would actually mask the boards wrong.

h.