John, I'm guessing that some photocopiers may be purposely set to a slight reduction to ensure that the edges are copied. Further, I doubt that most users care whether or not the reproduction ratio is exact. For the copier in question you could have copied at a nominal 102% to reduce the error once you had measured it.
Those in the graphic arts field would be more concerned with accurate reproduction ratios; for example, the cyan, magenta and yellow color printing plates have to match quite precisely. Those in the semiconductor and printed circuit board industries are extremely concerned about accuracy. They are more likely to require Bureau of Standards (now NIST) traceability. Some digital scanners and printers have a photoetched "comb" controlling the scanning, which I think is quite accurate. Of course, this only applies to the mechanical scanning dimension. The scale may be different for each axis, however. You might try using these. When I was printing vernier protractors on a Hewlett-Packard LaserJet printer some years ago I was impressed by its accuracy. In response to your comment about rulers, I just checked an old Westcott wooden ruler against a Ohio Forge steel tape, and they agree to within about 0.005" over 15". Gordon At 10:25 AM 7/24/99 , John Carmichael wrote: >But beware! I found out a while back that most copiers will not reproduce a >copy to the exact size that you program it to do. Yesterday, I showed the >surprised manager of Kinko's (a respected fotocopy shop) that when we >fotocopied a 16" ruler at 100 %, the copy measured 15 3/4" !!! We then >checked five different machines and none of them produced same-size copies >(except for a small digital copier). >The manager and I wondered if the machines could be calibrated and if they >are covered by the Bureau of standards? By the way, did you know that >different brands of rulers measure differently!? Be careful with those. (I >always use the same architectural ruler to avoid problems.) > >John Carmichael ><http://www.azstarnet.com/~pappas>http://www.azstarnet.com/~pappas > Gordon Uber [EMAIL PROTECTED] Reynen & Uber Web Design http://www.ubr.com/rey&ubr/ Webmaster: Clocks and Time http://www.ubr.com/clocks/
