RE: Lithium palladium vs. "normal" palladium
> Eric, > > Thanks for the information; it's amazing how much there is to learn about > pt/pd printing. > > > > 2 Moles of [Li, NH4, Na] Cl, to 1 mole of > > PdCl2. How you decide to dilute it is up to you. > > How do different dilutions affect the print (color, dmax, etc.)? Just out > of curiosity, which dilutions do you (and others) use? > The idea is to match the solution strength of the metal salts with that of the Ferric; either AFO or FO. One can get bad Dmax or extra contrast depending on which way the equation is set. > > > How does one make there AFO, or FO is equally > > important. The numbers are not etched in stone but the results nearly > are > > :) > > Not sure I'm following you here. Are you saying that there is an "ideal" > dilution of AFO/FO for a given dilution of pd, or are you simply saying > that the AFO/FO dilution, whatever it may be, plays a significant role in > print results? > Yes, equal to required needs. When you look at % solutions and matching them with molar solutions, that can be an easily lost battle unless you know the equivalent for each. What is a molar solution? A 1 molar solution is the formula weight to make 1 liter of solution. Note I did not say add to 1 liter different solution. You can see in Ware/Malde there is a .7M solution of both the ammonium based palladium and platinum salts. The AFO is mixed at 1.4M. And I see the mixing of solution / reactants like this, If you are going to error on one side or the other you should error on the side of too much of the catalyst. So for mixing your metal salts, the extra would come in the form of a little extra chloride cation _ the sodium, ammonium, lithium, because with out it, the PdCl2 can not get into solution. And like wise, add extra AFO,FO because without it the precious solution of PT / PD will sit in the paper with no enough available Ferric to convert it into the new "black" state that forms your print. I mix my solutions as close to .7 M as possible. The B&S solution are quite a bit less than .7 M. That is not to say that they are wrong, but it might be a possible reason that many seem to require and extra coating to get good Dmax. Jeffrey Mathis has an extensive write up about optimizing the solutions. I might not agree with everything there, the idea is a good one. Coat a variety of amounts, and see what gives you the best Dmax, color, contrast. Find out what this ingredients really do, not just what someone else has settled on. Eric Neilsen Photography 4101 Commerce Street Suite 9 Dallas, TX 75226 http://e.neilsen.home.att.net http://ericneilsenphotography.com Skype ejprinter
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