> > I'm just curios, how did they design those curved traces at the time? In the old days those curved traces were made using black opaque tape on a sheet of transparent polyester film (Commonly called Mylar - a DuPont trademark). The tape was sort of like "Masking Tape" and could be bent into various curves. After the taping was done the polyester film with the black tape was photographed and usually a negative was made using some sort of high-contrast film (The photo experts on the forum will know more). It was this negative film that was used to photofabricate the board. The "Black tape" layouts were typically made at 2x size or larger. We still have some *very old* layouts like this at work - if you try to pick them up the Black Donuts and Black tape fall off the polyester film... so you are left holding a sheet of film with a little adhesive residue - and Black donuts and tape all over your shoes :-) -- Mark -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist