First, it is exposed under strong light with a random dot screen placed on top of it ( called an aquatint screen in fine art printing or a stochastic screen in commercial printing ).
2.
They were scanned from copies of the school magazine-the earliest photo of Eric Livesey ( left ) processed using a coarse dot screen, the Kevin Comrie photo ( middle ) was simply photocopied, and the Tony Walsh image ( right ) was printed on a slightly more sophisticated offset litho machine . keithbates51 talk ) 07 : 15, 25 October 2016 ( UTC)
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