Re: step wedges; POP and gold toner

Date view Thread view Subject view Author view

From: Sandy King (sanking@clemson.edu)
Date: 10/31/01-05:30:31 PM Z


Shannon,

Much of the previous discussion has focused on making prints. Your
problem appears to be in the density of your negatives.

That being indeed the case, and correct me if I misunderstood you,
you will need to adjust the exposure of your negatives by rating the
film at a higher EI. I can't tell you exactly how much because that
will depend on several factors, including how you meter, developer in
use and film. However, try doubling or even quadrupling the EI that
you use to meter.

If the question is merely that the shadows in your prints are too
dense by about two stops, that represents an overexposure in printing
of about two stops, equivalent to a density difference of 0.60.
Reduce your exposures by a factor of .25 or .50. For example, if the
offending exposure is 100 seconds, reduce to 50 seconds to for a
density change of minute 0.30, or to 25 seconds for a change of 0.60.

With all POP processes the key to good contrast is to keep the
density of your negatives low in the shadows. Anytime negative shadow
density goes over about 0.40 it becomes very difficult to get good
contrast from POP processes because of their self-masking feature.
Lacking a densitometer, a rough guide to 0.35 on the exposing
negative would Step Four on the transmission step wedge (Stouffer,
Kodak, etc.).

Sandy King

> A few days ago, I think I read on this list that two steps on the
>step wedge equals one stop. Is that correct? I am trying to figure
>out how to change my EI, because the shadows in my negatives shot at
>320 are about two steps too dense. Does that mean I'm over exposing
>one stop, approximately?
>
>Also: I am printing on Centennial POP. The brochure that came with
>it says to replenish the gold chloride toner after one 8x10 print. I
>cut my 8x10 sheets into four rectangles, so I thought that I could
>tone and fix four of these small prints, one after the other, before
>I had to replenish. But, that doesn't seem to be the case. After two
>prints, the toner is exhausted and doesn't replenish easily by
>adding 6mls of solution A and B, as advertised. I am wondering if I
>should hold all four prints in water and then tone them all at once
>in the gold toner? CAn you do that?
>
>--shannon

-- 


Date view Thread view Subject view Author view

This archive was generated by hypermail 2b30 : 11/02/01-08:55:27 AM Z CST