How can one go about printing both top and bottom sides of a board in negative (e.g. PS_INVERTED device) so that they both appear next to each other in one file? If this is not possible directly within Eagle, is there some post processing of the Postscript files that can achieve this, so you don't have to put your transparency material through the printer twice - or waste two sheets?
I actually figured out a nice clean way to do it. I just generate the two negative images in two postscript files. They look like this:
The two postscript files define some reference points and a bunch of common functions for drawing lines, octagons, etc. So, I just extend the top side artwork 2X to the left, and draw the bottom side artwork in that space. The whole thing is done in a bash script, and the result looks like this.
This makes it very easy to print the artwork without wasting film, and also to align the two sides just by folding the slide over on itself. Note also that there is no conversion to and from any file format other than postscript, so there is no risk of messing up the scaling or aspect ratio.
