Spehro said:
We used to reduce it 2:1, I imagine some fine stuff would have been
done 4:1.
Made it difficult to check the footprints.
Best regards,
Spehro Pefhany
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.