Re: NA2 For Pt/Pd BLENDS

DEAR SANDY (et al.)
     Thanks so much for sharing all of your experience on this topic.
     Sandy, I use Sodium Citrate developer at 100 F and have repeatedly
found definite differences in image color between 100% Pd and 1:3
Pt/Pd, all other variables being constant.
    What I understand from your last posting is that I will get
contrast changes with my blend similar to what one gets using Na2 with
pure Pd. Thanks. This will be a great starting point for testing
saving me a lot of wandering in the forest.
    Thanks again!
       CHEERS!
         BOB

----- Original Message -----
From: Sandy King <sanking@clemson.edu>
Date: Friday, December 5, 2003 6:03 pm
Subject: Re: NA2 For Pt/Pd BLENDS

> Clay,
>
> In looking back through my notes I now realize that I put my mouth
> ahead of sound analysis. It is now apparent to me from my own data
> that my method of testing Na2 in Pt/Pd blends used such small
> quantities that the amount of pure palladium continued to be the
> dominating factor, so in essence I got the same ES with pure
> palladium and blends that contained as much as 50% platinum.
>
> Fortunately my observations had nothing to do with the essential
> testing I did, which was to compare the impact of different UV
> sources on various blends of palladium and platinum, except for
> the
> fact that the amount of Na2 used was too small to merit analysis.
>
> However, without Na2, or any other contrast controlling agent in
> the
> mix, I got virtually the same exposure scale speed, and color from
> the use of: 1) 100% pure palladium; 2) a 1:3 blend of Pt/Pd; and
> 3)
> a 1:1 blend of Pt/Pd. This was with a developer of 25% potassium
> oxalate, used at 120 F.
>
> Which is to say again, I really can't see any reason for putting
> any
> platinum in the blend except for the Na2 which is needed for
> contrast
> control.
>
>
> Sandy
>
>
>
>
> >On Dec 5, 2003, at 2:16 PM, Sandy King wrote:
> >
> >>Clay,
> >>
> >>That is interesting, but it definitely worked here.
> >>
> >>Have you tested this?
> >
> >Not personally. I'm just parroting what I read last night. Next
> time
> >I do some printing, I'll run an endpoints test and do a test with
> >pt/pd/FO at 3/3/6 and one with Na2/Pt/Pd/FO at 2/2/2/6 and see
> what
> >I get.
> >
> >Clay
>
>
Received on Sat Dec 6 11:38:53 2003