RE: NA2 For Pt/Pd BLENDS

Sandy, Am I right to understand then, that what you are saying is that Na2
does not effectively control contrast with a blend of PT and PD? I have not
see Dick Arentz' writing, nor that of B&S, other than the paper posted on
the B&S site.

Eric Neilsen Photography
4101 Commerce Street
Suite 9
Dallas, TX 75226
http://e.neilsen.home.att.net
http://ericneilsenphotography.com
 

> -----Original Message-----
> From: Sandy King [mailto:sanking@clemson.edu]
> Sent: Saturday, December 06, 2003 1:59 PM
> To: alt-photo-process-l@sask.usask.ca
> Subject: Re: NA2 For Pt/Pd BLENDS
>
> Bob,
>
> I meant to say the opposite, that is, you get about the same
> contrast, speed and color with 100% palladium as with a 1:3 blend of
> platinum and palladium. The color is very warm brown in both when
> developed in a 25% solution of potassium oxalate at 120F. If you go
> all the way to a 1:1 blend of platinum and palladium the color is
> just a tad less warm. This is without the addition of any Na2.
>
> With sodium citrate at room temperature, which I have also used with
> palladium, the color of both pure palladium and pt/pd blends is much
> less warm, and with ammonium citrate at room temperature the color of
> pure palladium is almost neutral, just slightly warm.
>
> Conditions of RH and temperature may give different results, but the
> above is what I see in my working conditions of about 70F and 55-65%
> RH.
>
> Considering all of this it makes sense to use pure palladium, control
> contrast with Na2, and get the color you want with choice of
> developer.
>
> Sandy King
>
>
>
>
>
>
>
>
>
> >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 23:52:36 2003