[alt-photo] Re: Zia standard solutions

[Loris Medici]

I don't think there's a definitive answer to that. For instance, I remember Sam Wang suggesting dilution of argyrotype soln. 1+1 with water (for some specific reason which I can't remember right now) and someone tried it (was it Paul Viapiano?) and got better results, "for his set of parameters". I guess one has to test and see if dilution (w/o affecting stoichiometric balance!!! That is, w/o affecting the molar equivalence between the compounds involved) works for them.

Regards,
Loris.

On 20.Tem.2010, at 18:55, Christina Anderson wrote:

> Jalo and others,
> (Oh my, I'm approaching my ten-post limit for the day)
> Jalo's point brought up a topic I have been meaning to ask.  If Jalo just uses the 25ml and adds the chemicals, he essentially has just diluted the solution by a very teeny amount.  Years ago I read about diluting the combined pt/pd solution 50% with water and double coating. This was to get around the very absorbent Rives BFK situation.
> 
> My question is this:  has anyone diluted the more expensive precious metal solutions with water as a general practice, either to save $$, or to deal with absorbent papers, or whatnot? I know that if the ratio of ferric to pt/pd goes awry, you get a weak print (seen that in workshops), but given the ratios staying the same, maybe even a 10% or 20% addition of water to the total mix might be possible as general practice? Just wondering if anyone does this, and if so, at what point does it not work.  The person in question was double coating so it wasn't going to affect the total amount of pt/pd on the paper, so I am asking about lessening that total amount.