[alt-photo] Re: dilution of pt/pd

[Christina Anderson]

Thanks you guys,

Clay, this makes sense, the "per square inch" factor.  I, too, have noticed when students get bronzing it is due to being stingy with the coating (when I ask them the drop count they used they usually are using 1/3 too little or they are coating a larger area than the drop count they measured for). 50% produces an anemic black, but perhaps somewhere between, say, 10%-30% there may be a possibility. I'll just have to try it when I get back to MT, but thanks so much for this very specific advice.

I've tested changing the range of ferric and at a very quick point the print is anemic. I've tested humidity. Dilution would be good.
Chris


Christina Z. Anderson
christinaZanderson.com

On Jul 21, 2010, at 5:04 PM, Clay Harmon Website wrote:

> I have accidentally printed on a piece of paper coated with a 50% diluted coat of palladium and ferric. The result was an anemic black and a generally weak print. It also was badly solarized on the edges where the brush strokes tailed out. This squares with my observation that solarization is most likely to occur where there is too much exposure of too little coating in the paper.
> 
> It seems to me that the main point of making concentrated and molar-balanced solutions of palladium(or platinum) and ferric oxalate is to ensure that there will be sufficient concentrations of the solution per square inch of print to yield a really deep black in those areas where the exposure is complete. Unless you print on completely wet paper, the water portion of the solution has evaporated and all that is left is the solution, the paper fibers, and whatever residual humidity from the coating solution remains in the paper fibers. 
> 
> Clay
> On Jul 21, 2010, at 4:06 PM, Christina Anderson wrote:
> 
>> So,
>> 
>> Paul V and Sam have diluted argyrotype to satisfaction apparently, even great satisfaction.
>> 
>> Sam and I have diluted cyanotype to satisfaction--smoother but slower exposure is the downside.
>> 
>> Has anyone aside from diluting 50% and double coating as Stuart Melvin did for BFK, diluted pt/pd to satisfaction and if so to what amount? And if so, to benefit of more absorbency, saving money, what?
>> 
>> Chris
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