Any advantages to adding platinum with Na2 method?

I am using palladium and the Na2 method according to Dick Arentz method. I.e ferric oxilate and Palladium (6 & 6) with Na2 as contrast enhancer. I noticed that some also add some platinum to the mix along with the palladium instead of pure palladium. What are the advantages, if any, when used with Na2? And what effect does this have on the print and when does one use this? Thanks.

I believe it makes the prints cooler in colour and your bank balance redder.

J

The NA2 is a dandy contrast agent, far superior to the modified "evil #2" ferric oxalate of the traditional method. I use quite a bit of platinum and NA2 on my prints and my prints are closer to neutral than warm toned. I go into quite a bit of detail on how I print on my web site.

When I took Tillman's Pt/Pd printing workshop, he said that platinum is not compatible with sodium chloroplatinate, and that attempting to substitute platinum for palladium will lead to catastrophic results with the NA2 contrast agent.

Based on his advice, I haven't consciously tried it. However, I've often wondered about the fact that during the course of a working session, its possible to switch between the traditional process (ferric oxalate 1 and ferric oxalate 2 with some combination of Pt and Pd) and the NA2 process. It seems to me that when this happens, there will be some carryover of Pt into a subsequent NA2 mix unless the equipment is thoroughly rinsed. I don't rinse, and I've never had a problem, so now I'm not so sure.

Perhaps teh best answer is to try it to see what happens.

Guys thanks. Joe, excellent stuff! The advantages are color vs. contrast - cooler vs. warm toned it sounds. So, you control contrast with Na2 and color by adding platinum? I notice that you use potassium as a developer. I am using ammonium citrate that is supposed to offer a cooler print? Curious as to why you use the potassium instead of ammonium citrate? Also, Joe, I live in desert, lower altitude (phoenix), and use cot 320 - what advantages would I find by possibly adding humidity like you do? Thanks for all your help.

Scott Peters said:

Guys thanks. Joe, excellent stuff! The advantages are color vs. contrast - cooler vs. warm toned it sounds. So, you control contrast with Na2 and color by adding platinum? I notice that you use potassium as a developer. I am using ammonium citrate that is supposed to offer a cooler print? Curious as to why you use the potassium instead of ammonium citrate? Also, Joe, I live in desert, lower altitude (phoenix), and use cot 320 - what advantages would I find by possibly adding humidity like you do? Thanks for all your help.

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Scott,

Most people report that potassium oxalate adds speed to the sensitizer compared to either ammonium or sodium citrate.

Adding humidity will probably give more Dmax in your prints. The humidity here in South Carolina now inside in my house, with heating, is about 30%. This results in prints with much lower Dmax with DOP pt./pd. than I get if the humidity is raised to 60% or more. The difference can be quite significant.

Na2 is used as a contrast control with palladium. The more you add the more neutral in tone the print becomes, and you get more contrast. If you want neutral prints there are many ways to get them, including using ammonium citrate in place of oxalate as the developer with DOP palladium, or you could use a POP palladium process, substituting ferric ammonium oxalate in place of ferric oxalate and ammonium pallaidum chloride or lithium pallaidum chloride in place of the more commonly used sodium palladium chloride. There are probably about 10,000 ways you can make pt./pd. prints, but if the goal is just neutral prints there are many ways to get them without either Na2 or platinum.

Sandy King

The problem with adding platinum to the the sensitizer when using Na2 and palladium is that that the 'normal' potassium-platinum metal salt combines with the platinum in the Na2 mix and prevents it from working as a contrast agent. My chemistry is a bit rusty, but I think that it effectively changes the oxidation state of the Na2 from +4 to +2. The +4 oxidation state is why Na2 works as contrast agent in the first place, because it consumes the ferric at double the rate as the palladium in the reduction part of the reaction when the image is formed. The result is not catastrophic per se, but it just doesn't work like you want. Any increase in contrast that you do see is the result of the naturally higher contrast that you would get from a mix of palladium and platinum anyway.

Na2 is platinum.

Thanks Clay, There use to be a pretty good article On the Bostick and Sullivan web site explaining the oxidation rates and how Na2 works.

Mono, What Tillman was probably talking about is that you can't use potassium chloroplatinite with sodium chloroplatinate (Na2) the 2 don't mix. This is due to the oxidation rates being different as Clay was referring to.

Thanks Sandy, I will try adding some humidity as I would like a little more Dmax. I may also try some potassium developer and see how I like the results vs. the ammonium on some of my prints. Soooo many variables...I think that's why I like it so much. Scott

Scott Peters said:

Thanks Sandy, I will try adding some humidity as I would like a little more Dmax. I may also try some potassium developer and see how I like the results vs. the ammonium on some of my prints. Soooo many variables...I think that's why I like it so much. Scott

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Yes, there are really a lot of variables and that is one of the fun parts about pt./pd.

The bad part, at least for me, is that in spite of the 10,000+ ways of making pt/pd prints they never look as nice dry as when wet!

Sandy King

Sandy, sounds like you may like the 'finished' look of Carbon Printing better?

they never look as nice dry as when wet!

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Unless of course they are printed on baryta paper!

Scott Peters said:

Sandy, sounds like you may like the 'finished' look of Carbon Printing better?

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I do prefer the finished look of carbon prints, for *most* images . And whenever I show the two types together almost everyone else does as well. However, what we prefer is a conditioned aesthetic response so it would be wrong to assume that I think one process is superior to the other. The thing about carbon, however, is that the print looks great when wet, and often even better when dry.

Sandy

CraigK said:

Unless of course they are printed on baryta paper!

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I agree. If you can get the coating right on baryta a Pt./Pd. image can really glow. I plan to do nothing but carbon for the next 7-8 months, but next summer when the humidity is high I am going to really give palladium on baryta a serious run. The quality of your work in this area is really stunning.

BTW, I believe that Formulary has a baryta coated paper? Does anyone know if it works for pt./pd? I assume there is gelatin in the coating and if so it would probably work much better by by using just pure palladium. As I recall Mike Ware reports some incompatibility between gelatin and platinum.

Sandy King