From: clay (wcharmon@wt.net)
Date: 11/06/01-08:23:40 PM Z
OK OK OK. I'll ask a question re the earlier post on Pt/Pd calibration for
the stained Pyrocat HD negatives. I have several negative test wedges
developed at different times, which as you would expect, all have different
contrasts when the log exposure is plotted against the transmission density
of the resulting negative.
I have printed my assumed 'normal' development time negative test wedge with
Pd contrast mixtures of 11/1/12, 8/4/12, and 6/6/12 ratios of sensitizer #1
, #2 and metal salt, with the same exposure time on my UV unit. I have then
plotted the 'apparent' densities that my b&w densitometer reads on the
negatives against the reflective densities of the Pd test prints. The
result is remarkably similar to the curves that are in Dick Arentz's book,
only with much reduced absolute numbers for the negative transmission
densities. It seems to me that I now have a set of customized curves that
correlate the effective stain density present in my negative processing with
the resulting print density at a standard print exposure time. Am I being
too naive to believe that I can now use them exactly like the curves in
Dick's book to compute the correct contrast mixture and exposure time for
future negatives? It seems almost too simple and easy.
Ok, I did my part to stir the pot.
Clay
----------
>From: FotoDave@aol.com
>To: alt-photo-process-l@skyway.usask.ca
>Subject: Re: testing
>Date: Tue, Nov 6, 2001, 6:34 PM
>
>double checking ....
>
This archive was generated by hypermail 2b30 : 12/10/01-11:12:21 AM Z CST