Palladium Chloride Mixing

[Craig Alan Huber]

I'm mixing up some Palladium solution to print with (hopefully today). I'm starting with Palladium Chloride powder that I got several years ago in a bulk purchase several palladium printers went in on. Arentz' book suggests 10mg Palladium Chloride with 50ml water heated to 100 degrees F will make an approx. 20% solution. I started with this last night and still cannot get all the powder to go into solution. I tried re-heating a couple of times in a microwave, up to approx 120F but still have particulates in the solution. Could it be over-saturated?

[Eric James]

10 milligrams or 10 grams? 10 grams brought to a volume of 50ml would give you a 20% w/v solution. 10mg would cover the head of a thumb tack and make a 0.2% solution.

[Eric James]

Info at this link may help:

http://www.cartage.org.lb/en/themes/arts/photography/specialphot/metallicsalt/platino.htm

[Craig Alan Huber]

Thanks for the source pointer and other advice, Eric. Quoting from the source ...


"The most economical method is to use palladium chloride (PdCl2) in combination with sodium chloride in solution. 3.5 grams of sodium chloride are dissolved in 55ml. of warm distilled water and then 5.0 grams of palladium chloride are added and stirred until dissolved."

The ingredient I left out was sodium chloride. I also notice the source is recommending an approx 10% solution. I want to match what Bostick&Sullivan normally sells so I will consult with them on the % solution. And yes, I did mean 10g not 10mg :-)

-Craig

[Eric James]

I know next to nothing about the process but one of the sites suggested that PdCl2's aqueous solubility is poor and that the use of a co-salt enhances solubility, hence the role of the NaCl. Anyway, I'm glad you're making progress. I see we're neighbors - we live in LFP. Good luck! Eric

[Craig Alan Huber]

Since the source quoted suggests a solution that is approx 10%, I am now wondering how much difference the solution % will make in a print. I have mixed at 20% in the past (a few memory cells from 2006 when I last mixed are kicking in, telling me I actually did add NaCl back then), but I know of one other excellent Palladium printer that uses a 15% solution. Does anyone mix a 10% solution and get good printing results? It may be time for some experimenting ...

Craig

P.S. Eric - had no idea you were so close ... perhaps we could arrange a meeting some time?

[Kerik Kouklis]

Craig if you're starting with Palladium II Chloride (ie not sodium palladium chloride), you also need to add sodium chloride (table salt). I've always used these proportions:

5 gm palladium chloride
3.5 gm sodium chloride (non-iodized)
distilled or deionized water to make a total of 55 ml of solution

Kerik

[Craig Alan Huber]

Thanks Kerik. Your advice matches the source Eric provided, John Rudiak from View Camera January / February 1994. I have seen your prints and if this is how you are mixing Palladium solution (approx 10% solution), you are certainly getting good results. Just for fun I may try a 15% and a 20% solution (assuming I can get the metal salt to go into solution) and see how it affects the print. Someone else may have already done this experiment and if they would like to share results, great.

-Craig

[Michael Mutmansky]

Craig,

I've done some of that in the past. Going to a higher concentration allows you to increase the palladium density per unit of H2O, which will subtly increase the dmax of the print. However, to do that, you need to increase the amount of FO you are using proportionally, because you need to keep the amounts of PD and FO about the same in the solution to keep the chemical reactins balanced.

So, increasing the PD without increasing the FO will not really result in any benefit.

---Michael

[Craig Alan Huber]

I see that B&S offers a "Palladium Chloride No.3 Standard" mix that is a 15% solution.

As for the FO they sell, I see a 27% solution (for pd/pt) and another 20% solution (for kallitype).

Michael - When you refer to increasing the amount of FO proportionally to Palladium Chloride, could you elaborate a bit? I would like to try a mix of 15% solution Palladium Chloride as an experiment compared to the 10% solution. But what mix of FO would that imply for each? Would I be changing the ratio of each solution for coating the print? For straight Pd printing I usually go with the same number of drops of FO as Palladium Chloride. Sorry to be so dense on this ...

Thanks,
Craig

[Michael Mutmansky]

Think of it this way... When you mix equal parts of the traditional PD solution and the traditional FO mix for PD, you are essentially matching up the proper amounts of the various chemicals in solution that then dries on the paper. The concentration of that combined solution is fixed based on the amount of the chemicals in the two component solutions, and the presumption that you mix them 1:1. I've done the tests, you do want to mix them 1:1 when using the standard solutions.

If you increase the concentration of the PD from 10% to 20%, you will effectively have twice as much PD in the solution, so you only need 1/2 as much solution to achieve the proper amount of PD chemicals in the combined FO-PD mix. That means that you can make the same effective solution using 1:.5 mixes, instead of 1:1.

Now, consider that the paper can only handle so much solution per square inch (square foot, whatever). Lets say that you are limited to 2ml of solution per square foot. Normally, that would mean that you would do 1ml of FO, and 1ml of PD (10%) to get the proper 2ml total to cover.

However, if you use 20% PD, you only need .5ml to make the proper balanced FO-PD solution, so you end up with only 1.5ml of total solution. That may not be enough to cover properly, so you could add .5ml of H2O to bring it up to 2ml total, or you could add more FO and PD solutions to create a combined mix that added up to 2ml total. If you add more PD and FO, you ultimately get a condition where the two end up have a higher concentration PER SQUARE INCH on the paper, and it doesn't overload the paper with too much liquid.

You would have to use a 2:1 ratio of FO:PD to keep everything proper (because the PD is 2x as concentrated as the FO compared to the traditional formulas), so to get a full 2ml of mixed solution, you would want 1-1/3 FO and 2/3 PD to keep it balanced and at the proper total amount.

This ultimately results in a solution that is 1.3X more concentrated, so there is 1.3x as much useful chemical PER SQUARE INCH when the solution is dried into the paper.

If you can do a PD solution at 30% (which you should be able to, if I remember correctly) you would need 1/3 as much PD as FO. That works nicely, as the two combined equals 4 parts (3 parts FO and 1 part PD), which is normally easily calculated and measured if you are using pipettes, and even if you are using droppers. That would result in a solution that is 1.5x more concentrated on the paper. You would do 1.5ml of FO and .5ml of PD to achieve the proper amounts (achieving a 3:1 ratio, 2ml of total solution, and 1.5x the 'traditional' amount of PD in the mix)

And it can be done in one coating, rather than two coatings. The benefit is that it can be done in one coating in my mind. In my experience, single coating is much more consistently 'perfect' than double coating, so if you are looking to get a DMAX boost but wish to avoid coating flaws that sometimes come up because of double coating, this is a good way to do it.

Or, you could be really indulgent and double coat with the higher concentration solutions, but I doubt the payback in improved DMAX is worth the cost. You'd probably have a lot of wash-off.

Don't try to increase the FO percentage; it's near saturation, and it just won't be possible to get any more into solution properly.

---Michael

[Kerik Kouklis]

I see that B&S offers a "Palladium Chloride No.3 Standard" mix that is a 15% solution.

You might want to check with them on this. They describe it as Sodium Chloropalladite 15% solution (aka sodium palladium chloride). That does not mean it contains 15% palladium.

The formla I gave is ~15%

5 gm Pd + 3.5 gm NaCl = 8.5 gm in 55 ml of solution.

8.5/55 = 15.4%

[Harald Leban]

Craig,
it´s a fact that one cannot compare percentual concentrations so straight - chemistry uses a different system - the molarity . A 15% Palladate solution is around 0,5mol/l and a 30-35% FEO is around 1,5mol/l, so when using equal quantities for coating and knowing that you need 2mol of Fe(III) to reduce 1mol of Pd(II) you still have 50% FEO over.
If you like to use higher Palladate concentrations you should make the Ammonia salt instead of the Sodium compound (change the Sodiumchlorid against Ammoniumchloride) it will reach solutions up to 20% and higher without precipitation.
There could be troubles in increasing the FEO concentration because of lack of solubility.

I found a slightly different compound "Ferricoxacitrat" as a better choice for working with higher concentrations and deeper d-max......

allthebest

Harald

[Michael Mutmansky]

Harald,

That may be true, I'm not a chemist. However, I have done the tests to know that the FO to PD proportions are essentially optimized when the 'traditional' formulas are used without alteration.

Essentially, DMAX decreases if you deviate in either direction substantially.

[Harald Leban]

Michael,
the reason why it works with the traditional formula is because it´s well balanced in concentration. But double % concentration means also double molarity (if we put the increase of liquid density by side) - so your calculation is right when you decrease the quantity of Palladate in the same ratio you increase the concentration of it.

What I tried to explain is that some must use a higher Fe concentration to work with a more concentrated Palladate to reach a higher sensitizer concentration on the paper and finally gets better d-max.
We both know that it depends also a lot on the quality of the paper thats used - but with the right paper there will be a remarkable inkrease in density on the final print.

[Michael Mutmansky]

Ok, I see what you are saying, and it is (as expected) a more correct way of saying what I was trying to say.

BTW, I agree that the paper is often the biggest variable in this. The right paper can make a huge impact on the results.

[Craig Alan Huber]

Of course, now is when I wish I had paid more attention to high-school chemistry :-)

With egg-on-face (or should I eat some crow?) I admit I was only counting the Pd salt in the % solution, not adding in the NaCl as Kerik pointed out. Kerik - I am verifying off-line with Dick Sullivan, as you suggest.

Also many thanks to Michael and Harald for detailed descriptions of the chemistry and some practicalities of usage involved. At least in this case I am holding the paper as a constant (COT320) for a series of images. Coating with a 2" Richeson brush and 48 drops total solution over an 11x14 inch area I am getting nice results with a single coat.

Craig

[Craig Alan Huber]

And now, of course a new (but related) question: will I be able to use ordinary table salt for this mix, or will some lab grade be required? I assume I would want non-iodized salt. I went to the store recently to look, and was amazed at the number of salt products (over 10, not counting seasoned-varieties!)

Thanks,
Craig

[clay harmon]

Craig,

I use uniodized Morton's salt and have no problems.

[Michael Mutmansky]

Same here, but I prefer ammnoium chloride, so I started using that over the Morton's.

[Kerik Kouklis]

I only use pure Himalyan salt mined by Tibetan monks and carried by Nepalese Yaks from the depths of the famed Himalayan Salt Mines located at the foot of Mt Everest.

Nothing else works as well for pt/pd printing.

It's good on hard boiled eggs, too.

[clay harmon]

Great. Now the cat is out of the bag. At least you didn't tell anyone about the use of the ground residue from the pituitary gland of Manx cats as one of the better sizing agents on the planet.

[Craig Alan Huber]

You guys are just too funny.

I did find something close to the salt Kerik mentions (pure Himalyan salt mined by Tibetan monks and carried by Nepalese Yaks from the depths of the famed Himalayan Salt Mines located at the foot of Mt Everest), but instead it was carried by imported Mongolian Yaks. The local Safeway had this product on sale for only $89.99/oz ... do you think it's worth it?

[hmf]

I only use pure Himalyan salt mined by Tibetan monks and carried by Nepalese Yaks from the depths of the famed Himalayan Salt Mines located at the foot of Mt Everest.

Nothing else works as well for pt/pd printing.

It's good on hard boiled eggs, too.

Pardon my impudence, O esteemed ones, for dredging up this old thread, but I gather from the tone of this and preceeding comments that any old non-iodized table salt will do for mixing my palladium chloride.

From my pantry, this will include sodium silico-aluminate, dextrose and sodium bicarbonate for the regular, or yellow prussiate of soda for the Kosher variety.

Are these additives okay, or should I be looking elsewhere for table salt without the extras?