Re: Speed Point in PT/PD printing?

Speed Point in PT/PD printing?Sandy,

For starters, the issue of maximum black for PT/PD prints is in itself a question. This seems to be primarily because of the methodologies in use from one printer to the next. Unlike a given piece of manufactured paper with it's absolute formula for a sensitized coating, a PT/PD print can take on any number of appearances based solely on the operators tendencies, methods and/or for artistic purpose, an intentional or unintentional breaking of the normal rules for printing PT/PD. The combinations as you know, are endless.

n

  ----- Original Message -----
  From: Sandy King
  To: alt-photo-process-l@skyway.usask.ca
  Sent: Saturday, November 08, 2003 9:38 AM
  Subject: Speed Point in PT/PD printing?

  I am preparing an appendix on UV light sources for a book on Pt/Pd printing and I have some questions about speed point convention that need to be addressed in my comparison of different light sources.

  In silver printing the speed point is defined by ANSI standards as the exposure necessary to produce a print density of log 0.6 over B+F.

  In carbon printing, where we have an almost perfectly straight and linear curve, it has been my experience that the silver convention is not the most logical way to establish the effective printing speed of different light sources and I usually find that the point on the curve that has the first maximum black, or some very high percentage of maximum black, is a better indicator.

  But the pt/pd curve is of course quite different from both a silver and carbon curve, in fact somewhat intermediary between the two. So I am wondering how we should determine the speed point for for pt/pd printing? Do you think the silver printing convention is a good indicator, or would it be better to set the the point at Dmax, or at some percentage of Dmax? Or at some other point?

  Any thoughts on this by pt/pd printers would be appreciated.

  Sandy King
Received on Sat Nov 8 12:25:00 2003