Re: Using K instead of Na in Pt

Jeffrey D. Mathias ( Jeffrey.D.Mathias@worldnet.att.net)
Mon, 13 January 1997 7:35 PM

Richard Sullivan wrote:
>
>
> The only way I can see this happening is if you had enough heat to
> dissassociate the Na from the Cl so that you could could get 2 more Cl for
> the K2PtCl6. Since NaCl decomposes at 482 Deg. C, you've got to have a hell
> of a drying cabinet for this to happen.(Pot. Chloroplatinate a insoluble
> yellow powder) K2PtCl6 does not in my opinion make black specks in prints.
> Black specs are most commonly caused by ferrous particles (iron or steel)
> getting imbedded in the paper. This either in manufacture or after the fact.
> The particles can be microscopic and make pretty nice dots. One common
> source of particles is cutting paper with a razor knife and a steel rule.
> The knife shaves tiny particles off the rule. Self sharpening rotary or
> blade cutters are another source....

Dick,

No iron or steel in my paper. And with all all conditions equal,
printing cold did not produce specks and printing hot did. And once I
substituted potasium for sodium, no specks have occured since.

Also a chemist at Engelhard Corporation, Specialty Chemicals Division
(where I purchase my metal salts) told me that K2PtCl4 could convert
into K2PtCl6 at temperatures as low as 140F. It seems that K2PtCl6 is a
more stable salt. And, that this conversion is definatly aided by the
presence of sodium.

Anyway, belive it or don't. I have the prints to show it and I have not
had any problem with specks since using KCl with my PdCl2. By the way,
my results are reproducible. So I quess that even if I don't know what
exactly is happening here, I have found a solution to a problem. If
this works for someone else, good. I would not waste my time sending
this information, if I did not feel it would be benefitial to someone on
this list.

Thanks for the info on Mike Ware's ammonium solutions.

Jeff

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