I, too, thought printing on transparency with a laser printer would be the "solution." What I found, however, was that laser printers stretch the medium along one axis while heating it in order to bind the toner to it. That was OK for simple, not-too-dense circuits, but if you had fine-pitch parts, some of which were in use back in the early-mid '80's, you could get in to registration troubles. Further, the toner often wasn't dense enough. No HP laserjet I ever had would perform satisfactorily in this regard. The OKIDATA 1200 I once had did work adequately, though the media-stretch was still not satisfactorily addressed.

A Gerber plotter fixed all that.

RE