Re: Reduced Dmax with overexposure in Pt/Pd

[Eric Neilsen <e.neilsen@worldnet.att.net>]

Sandy,  It would be advisable to check with Dick and see what mixture he
coated for you.  ( another advantage to coating your own).  The results that
you state should be reported with amounts of platinum and what type as well
as the palladium.  Density results will vary with different light sources
and humidity ranges for platinum and palladium.  As you have seen,  your
results don't match what you have heard about SA lights and pt/pd.  Perhaps
it is all in the mix?

I have only seen an increase in speed and contrast with my mixtures after
switching to SA lights.

EJ Neilsen


----- Original Message -----
From: "Sandy King" <sanking@clemson.edu>
To: <alt-photo-process-l@sask.usask.ca>
Sent: Sunday, May 05, 2002 9:43 PM
Subject: Reduced Dmax with overexposure in Pt/Pd


> With reference to the Pt/Pd results that I reported earlier today,
> there was an  anomaly that surprised. When making test prints with a
> step wedge I generally overexpose by 2-3 stops. What I noticed in
> looking at the curves, and this was true of curves with all of the
> lights tested, is that there is actually a rather significant
> decrease in Dmax, or maximum density, with overexposure. By
> significant I mean between log 0.05 - 0.10.
>
> Is this something that one generally expects to encounter in platinum
printing?
>
>
> Sandy King
>
>
> --
>