Quote:
Originally Posted by Pat R
Hi Manny,
The gear streak information is interesting thanks for posting about them.
I agree with Steve and Luke I don't think that's what caused the
plate scratch marks. From what I understand the gear streaks
wouldn't be repetitive and the plate scratches are. As Luke pointed
out the same exact scratch can be found on the same subject multiple
times and on some sheets they same exact scratch can be found on
two different subjects.
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Pat,
Perhaps they're not "gear streaks" as I understood the term from the definition I found. There may be another term for the streaks in pressman nomenclature. One of these days if I have time I'll venture off to a printing forum and ask there what the streaks are called.
I still think my theory is correct. If you believe the Library of Congress' classification of T206 cards as relief prints, and you also assume that the owners of American Lithographic stuck to their area of expertise and operated a multi-color offset press, then the only valid explanation is that the scratch was on the rubber blanket roller and not the printing plate.
The Occam's razor explanation is that some kind of machine feed malfunction caused the rubber roller to bounce up suddenly, grazing the surface of the relief plate at a high speed, thus causing a scratch on the surface of roller which would hold ink and transfer to the card in the same spot each time. Either that, or simply that the roller became worn and scratched with use.
Because of the constant spinning of the roller, the scratches took the form of a helix wrapping around the cylinder, which translated into diagonal lines on the paper. The steepness of the scratch I guess depended on the speed of the press when the scratch occurred.