U of S | Mailing List Archive | alt-photo-process-l | Re: curves and gum and Christopher James book

Re: curves and gum and Christopher James book

Folks: Several of you have responed to Henry's question with suggestions of what he might do--but that was not his question. He wants to know--and I do too--how one person's curve for a positive can look much like another's curve for a negative. One answer seems to respond to his question, but I don't understand it--here it is:

You have to REALLY pay attention to the curve mode being used to display the curve. A curve calculated for graphic mode (applied to a positive) will, on the surface, look exactly the same as a curve applied to a negative -- BUT since PDN users generally work in binary mode it is this change of mode which functions to invert the curve.

What is a curve calculated for graphic mode? Why will it look exactly the same a a curve applied to a negative. What is binary mode as opposed to graphic mode?

Thanks. Charles Portland Or