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 Fri Dec 5 16:07:20 2003
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