The last time I used tape was in college and that was used on a lathe-type PCB machine. After college, everything was done in a CAD system (though schematics were drawn and netlists entered by hand for a few years). The boards were done by a positive system, too, so multi-layer and traces could be quite fine (three traces between .100" spaced IC pads were common).
Make 2:1 or 4:1 models of each footprint?
That really means "pen" size zero (the smallest in the system).
There still seems to be a units inconsistency involved.
?-)
Who said anything about tape (for fine lines)? A good drafting pen will give lines far finer than those rolls of tape. And for finer lines, look at the bills in your pocket, which were counterfeited by (crudely speaking) scratches back in those daze. I will not instruct anyone how to counterfeit paper currency, even the older-printed version (read: silver certificate age). Some of the techniques to do so were useful to make fine lines for PCBs, which was all i cared about.
Photo reduction is a very excellent tool. Have even used a photo technique to make negatives of both sides of PCBs. Remember the Altair computer? I made negs of the PCBs, patched where needed, then positives for added corrections and revisions including removing the mess of jumpers. Resulting improved PCB was made and sold in the hundreds near cost. Altair owner sent me a letter saying those copies (which were NOT the same due to circuit improvements at minimum) were "copyrighted" and virtually blackmailed me to stop. I also made copies of the BASIC tapes and included inverse assembly language listings, which he said were "patented"; he virtually blackmailed me to stop that as well. Nothing had been copyrighted and the boards i made were out of the bounds of any purported copyright (new and different circuitry). Software could NOT be patented in those daze. Also, the inverse assembly listing was never created by him either directly or indirectly; he had ZERO ownership.
up
the
tape.
That is a whole different pan of sknarr then.
?-)
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