RE: Lithium palladium vs. "normal" palladium
Loris, Thanks for spelling this out for me. Most of this chemistry talk is a little over my head (I should have paid more attention in those chemistry classes...), but seeing some numbers in there really helped. :) I think my confusion on this matter is finally starting to clear up (we'll see how long this "clarity" lasts, hehe). Thanks to those who attempted to explain this stuff to me, on- and off-list. Camden Hardy camden[at]hardyphotography[dot]net http://www.hardyphotography.net On Wed, January 17, 2007 1:21 pm, Loris Medici wrote: > Hi Witho, > > Thanks for bringing this up. I did some calculations and I'm quite > confused right now. See below: > > LiCl (Lithium Cloride) 1 Mole = 42.394g, > 1.4M solution = 59.3516g in 1000ml (5.93%) > > (NH4)Cl (Ammonium Chloride) 1 Mole = 53.4912g, > 1.4M solution = 74.88768g in 1000ml (7.48%) > > PdCl2 (Palladium(II) Chloride) 1 Mole = 177.33g, > 0.7M solution = 124.131g in 1000ml (12.41%) > > Li2[PdCl4] (Lithium double salt of Pd) 1 Mole = 262.11g, > 0.7M solution = 183.477g in 1000ml (18.34%) > > (NH4)[PdCl4] (Ammonium double salt of Pd) 1 Mole = 284.31g, > 0.7M solution = 199.017g in 1000ml (19.9%) > > (NH4)3[Fe(C2O4)3].3H2O (AFO) 1 Mole = 428.067g, > 1.4M solution = 599.2938g in 1000ml (59.92% - say 60%) > > 2 Mole salt + 1 Mole PdCl2 -> 1 Mole Pd double salt. Therefore > > 2 LiCl + 1 PdCl2 -> 1 Li2[PdCl4] > 2 (NH4)Cl + 1 PdCl2 -> 1 (NH4)2[PdCl4] > > If you compare the atom counts on each side you'll see that the > equations are correct. > > To Camden: > > Let's assume you have 25g PdCl2 (current special price for this amnt. > for APUG.org members is $262.50 (+ 135g Ferric Oxalate for free - > kudos B&S). .. > > You can make 200ml (201.45 actually) 0.7M Li2[PdCl4] solution with > this amnt. of PdCl2 (25g / 12.41% - see info provided for PdCl2 above.) > > You'll need > > 25 (1) / 177.33 (2) * 2 (3) * 42.394 (4) = 11.95g LiCl. > > or > > 25 (1) / 177.33 (2) * 2 (3) * 53.4912 (5) = 15.08g (NH4)Cl > > Notes: > (1) Amnt. of PdCl2 you have > (2) Molar Mass of PdCl2 > (3) 2:1 salt to PdCl2 ratio > (4) Molar Mass of LiCl > (5) Molar Mass of (NH4)Cl > > Calculate your costs according to the info I gave you above. > > To Witho and all: > > Lets assume you want to use 60% AFO as iron sensitizer, this is 1.4M > solution. If the molar ratio of AFO to Pd double salt is 2:1, then the > Pd double salt solution should be 1.4 / 2 = 0.7M. This is totally > consistent with the formulas given in Mike Ware's "The > Platino-Palladiotype Process" article... (Sensitizer's concentration > is 1.4M whereas the Pd double salt concentration is 0.7M.) When I > crosscheck this using Jeffrey's metal solution calculator, I can see > that he uses 1.4M Pd double salt for 1.4M AFO sensitizer - in other > words 2x of what is really needed. Isn't this wasting precious metal? > (I always had the feeling that I was loosing Pd when doing Ziatypes, > because the clearing bath was a light shade Pd brown - instead of the > yellow I get in other iron processes...) This is confusion #1... > > Also, when I check the amount of salt and PdCl2 for making up the Pd > double salt solution (from the book "The New Platinum Print" by > Sullivan and Weese, see page 76), the amounts I find are not > consistent with the amounts stated. > > The book says 1.7g LiCl + 2.3g PdCl2 + water to make 25ml, if we > interpolate this as we're using 25g PdCl2 -> > > 25 / 2.3 ~= 10.87, 10.87 x 1.7 ~= 18.47 <- the amnt. of LiCl needed > according to the book. Instead, the formula tells us we actually need > 11.95g of LiCl2 - in other words, ~1.5x times. This is confusion #2... > > I'd like to hear your comments confusions #1 and #2. What am I missing? > > Thanks in advance (and for taking the trouble of reading all this up to > here), > Best regards, > Loris. > > -------------- Quotation below -------------- > > Hello Eric, > > It is good that you mention this. > > I did some reading again last week on the available chemistry publications > and there is something my eye fell on. Mike Ware states that the molar > ratio > of ammonia ferric oxalate to ammonia tetra chloro palladate is 2 :1 to > complete the reaction: > > Reaction 1 > > hv = 2[Fe(C2O4)3]3 => 2[Fe(C2O4)2]2- + C2O42- + 2CO2 > > Reaction 2 > > [PdCl4]2- + 2[Fe(C2O4)2]2 => Pd + 2[Fe(C2O4)2]- + 4Cl- > > But, if you read the manual of Jeffrey Matthias (which I took for a long > time as my guide) you will see that he uses a ratio of 1:1 > > (NH4)3Fe(C2O4)3.3H2O >exposure> Fe(C2O4)2 + 3(NH4) + 3H2O + 2CO2 > > 3Fe(C2O4)2 + 3Li2PdCl4 + 3(NH4) + 3H2O => > (NH4)3Fe(C2O4)3.3H2O + 2(FeCl3) + 6LiCl + 3Pd + 3(C2O4) > > And Jeffrey states also : 'Or other metallic salts could be substituted. > Every three sensitizer molecules will pair with three metallic double salt > molecules, a one-to-one ratio (1 metal salt for 1 sensitizer).' > > This difference is substantial. I asked Mike Ware about it and Jeffrey > Matthias. Jeffrey replied me as follows : > > 'Remember that my work is based on empirical study, not theoretical. This > means that I am explaining things as they show themselves to behave > through > experimentation, not by the science of what they should or are doing. I > realized that I do not have the training and experience in ionic theory as > others, but I did have the time and patience to carefully run some > calibrated experiments. > > If the suggestion is that a print can be made with less metal than the > threshold, the result will be a weak print. Additional metal will just be > wasted. The statement: > "The correct stoicheiometry for trisoxalatoferrate(III) to > chloropalladate(II) in the sensitizer is indeed 2:1."(quoting Mike Ware in > an e mail to me) " is hard for me to understand. This is why I like to use > the compound's formulae rather than its name. I suspect that what is being > called 2:1 is the same as I have called 1:1. The bottom line is figuring > how > much of each substance to put into the solutions. What I call 1:1 is > consistent with historic formulas and works. If this is really 2:1 then so > be it. But, if it is suggested that twice or half as much sensitizer is to > be used or twice or half as much metal solution, I know that will produce > a > problem in the print.' > > Of course my suggestion to Jeffrey was not 'that a print can be made with > less metal than the threshold' but that you loose a lot of metal if the > ratio of the reacting compounds is not right. My suggestion is to run a > series of new tests with the different (2:1) ratio's. > > I have not calculated the B&S concentrations so I can't say from what > equations they start. Maybe Richard can tell us some more about it? > > Witho > > -----Oorspronkelijk bericht----- > Van: Eric Neilsen [mailto:ejnphoto@sbcglobal.net] > Verzonden: woensdag 17 januari 2007 0:52 > Aan: alt-photo-process-l@usask.ca > Onderwerp: 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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