Homebrew_PCBs

----- Original Message -----
From: grantfair2001
To: Homebrew_PCBs@yahoogroups.com
Sent: Saturday, December 13, 2003 2:21 AM
Subject: [Homebrew_PCBs] Printing pcb patterns negative or positive


I use a Panasonic KX-P6500 laser printer for making prototype boards
with Dyna Art paper, which seems to work fairly well for me. However I
am thinking of trying to make some silk screens for small volume PCBs
and I think I need to be able to print a "positive" of my PCB pattern
onto transparency in order to make the silk screen.

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.

I use Ivex Winboard for my PCBs, and to do this would require another
Ivex product costing $199.00.

However there may be drivers or other ways to do this, can anyone advise?

Grant

1. see if you can get an updated printer driver that will allow whit on black.

2. The old version of Pentalogix Viewmate had the capability of white on black printing as an option. The current version does not, but you might be able to write them to get an older version. It was a freeware gerber tool.

Ron

[Non-text portions of this message have been removed]

> I use a Panasonic KX-P6500 laser printer for making prototype boards
> with Dyna Art paper, which seems to work fairly well for me. However I
> am thinking of trying to make some silk screens for small volume PCBs
> and I think I need to be able to print a "positive" of my PCB pattern
> onto transparency in order to make the silk screen.
>
> 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.
>
> I use Ivex Winboard for my PCBs, and to do this would require another
> Ivex product costing $199.00.
>
> However there may be drivers or other ways to do this, can anyone advise?
>
> Grant
>

> am thinking of trying to make some silk screens for small volume

> and I think I need to be able to print a "positive" of my PCB

> onto transparency in order to make the silk screen.
>
> By positive, I mean that the copper tracks will appear white when
> printed on paper, and etched portions will be black. My PCB

> does the usual "negative" print - copper tracks are black, etched
> areas white, but not the positive print.

> 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.

>
> 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.
>

--- In Homebrew_PCBs@yahoogroups.com, Alan King <alan@n...> wrote:
> 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

> In message 352, list member Tom stated:
>
> "BTW, the screen printing emulsions are negative acting so you will
> need positive films emulsion side up."
>
> So I guess you are saying that my laser printed PCB patterns (on
> plastic sheets) are positive as is, and I have my terminolgy
> backwards. So I can use these with "negative acting screen printing
> emulsions" to get the silk screens I need to put resist ink on the
> copper which is not to be etched?
>
> Grant

--- In Homebrew_PCBs@yahoogroups.com, "twb8899" <twb8899@y...> wrote:

> Grant,
>
> Most screen printing emulsions are negative acting. Expose them using
> a postive image of your circuit board where opaque black is the
> copper and clear areas are etched away. The black areas on your film
> positive will prevent the UV exposure from making the emulsion hard.
> The areas that didn't get UV light will wash out leaving an open area
> in the screen for ink to go through during printing. The film
> positive should also have it's emulsion on the side that contacts the
> screen emulsion when UV exposing. This is really important if you are
> doing fine line work.
>
> Tom

> Grant,
>
> Most screen printing emulsions are negative acting. Expose them using
> a postive image of your circuit board where opaque black is the
> copper and clear areas are etched away. The black areas on your film
> positive will prevent the UV exposure from making the emulsion hard.
> The areas that didn't get UV light will wash out leaving an open area
> in the screen for ink to go through during printing. The film
> positive should also have it's emulsion on the side that contacts the
> screen emulsion when UV exposing. This is really important if you are
> doing fine line work.
>
> Tom

>
> I'm really confused. Black areas are where copper is.

> over the emulsion result in it washing away.

> to me.

> Steve wrote:
>
> >
> > I'm really confused. Black areas are where copper is.
>
> Exactly.
>
> But black areas
> > over the emulsion result in it washing away.
>
> Again exactly.
>
> This isn't making sense
> > to me.
>
>
> If black areas are where the copper is, but instead you need black
> areas over what to remove, then you need a negative of the copper areas
> image to expose the emulsion.

> Most screen printing emulsions are negative acting. Expose them using
> a postive image of your circuit board where opaque black is the
> copper and clear areas are etched away.

>So I guess you are saying that my laser printed PCB patterns (on
>plastic sheets) are positive as is, and I have my terminolgy
>backwards. So I can use these with "negative acting screen printing
>emulsions" to get the silk screens I need to put resist ink on the
>copper which is not to be etched?

--- In Homebrew_PCBs@yahoogroups.com, JChavez@s... wrote:

> Where can I get "negative acting screen printing
> emulsions"?
>
> TIA,
>
> Javier.

> "BTW, the screen printing emulsions are negative acting so you

> need positive films emulsion side up."
>
> So I guess you are saying that my laser printed PCB patterns (on
> plastic sheets) are positive as is, and I have my terminolgy
> backwards. So I can use these with "negative acting screen printing
> emulsions" to get the silk screens I need to put resist ink on the
> copper which is not to be etched?