Eric Neilsen (ejnasn@laplaza.org)
Sun, 31 Jan 1999 12:26:43 -0600
THis should have gone to list as well.
-- Eric J. Neilsen 7910 Treehouse Ln, Apt 1095 Dallas, TX 75231 214-378-8383 http://laplaza.org/~ejnasnattached mail follows:
Different printers will give different answers to those questions. In developing my printing method, I evolved through the use of Pot Chlorate (Sol B), then I used 3% Hydrogen Peroxide in my coating solution. All along, I was aware that platinum was much shorter than palladium on the contrast scale. However, what one learns can be quite contradictory to what one was taught. And now some 17 years later, I use what ever is most appropriate for the print. A cop out ? perhaps.
Having found the use of chlorate the most objectionable, I no longer use it except to show it to students. The use of Hydrogen Peroxide in the coating solution is fine if you don't use much platinum, and especially, if you use ammonium based platinum it is a definite, DO NOT USE. It will convert the red platinum salt into the yellow platinum salt, rendering it useless for printing. The dichromates have been added to the coating solution but not by me. I simply don't have the time to run more and more test. With all the above methods, a separate solution of the contrast agent can be added to the coating solution. There was quite a discussion of micro pipettes recently. This is how I add my H202 to my coating solution. I use a pipette that measures up to .10ml in .01 increments. Using this type of measuring instrument, one could easily deliver to the coating solution an appropriate amount of any of the contrast agents by creating a solution of sufficient strength. It is important to remember that the solutions may change over time. THe B solution in the traditional chlorate method will smell of chlorine. the breakdown of the chlorate making it less effective over time. Hydrogen peroxide losses O2, and I am not sure what happens to dichromates, but it has been discussed on the list that they too breakdown over time. The point? mix up small batches, but not so small as to be hard to duplicate with the scale available to you.
I use a pot oxalate developer, so dichromates (K, NA, and NH4 ) will work in the developer to change contrast. I have yet to investigate whether they also influence color. Sodium based chemistry will produce prints that are warmer, and ammonium those that are cooler. Something to consider is carrier over from print to developer. What will be the effect over time? will it build up in the developer?
Most printers that I know use the dichromates in the developer. Dick Arentz has a upcoming book from Focal press ( a updated version of his 30 page booklet) that I'm sure will go into the use of dichromates in a pot ox developer. Kerik Kouklis posted Dicks' formulas sometime back. I have them somewhere, I have just sold my house and temporarily moved Dallas where I am now setting my studio. I'm also writing a book on my method of printing and sharing my insights of 17 years. It is a slow process (book writing that is).
> I've been printing with B-S kits and now am venturing out on my own. It > seems there are nearly as many different methods and controls as there > are printers. I'm trying to wade through it all to find what works for > me. >
Good move to get away from kits. They are VERY VERY expensive. Engelhard is where I get my platinum, palladium, gold chloride, etc. I make my own ferric oxalate. I haven't tried it, but Artcraft also sells Ferric Oxalate, it may be worth looking into. You can also vary the strength of solution to change contrast.
The formulary is running workshops this summer up in Montana. You might consider taking a class to meet other printers.
Have fun.
-- Eric J. Neilsen 7910 Treehouse Ln, Apt 1095 Dallas, TX 75231 214-378-8383 http://laplaza.org/~ejnasn
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