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Serebrutype: Ruthenium developed out with silver nitrate

Ruthenium's applications in alternative process printing are too rewarding to ignore. Whereas for the past 170 years ruthenium eluded all attempts to use it for printing or even toning, the deliberate introduction of ferrous iron into a solution of ammonium ferric oxalate has at least tamed the ruthenium beast somewhat. In a new article on alternativephotography.com (here, in a new window), I lay out the formula for developing out ruthenium with silver nitrate. Note that toning is only practicable for strong, contrasty images as gold and palladium reduce density and contrast in the final image. Forthcoming soon are formal notes on ruthenium's use with palladium, gold and platinum -- and possibly with rhodium.

TIP FOR PREPARING AMMONIUM FERRIC FERROUS OXALATE (OR SODIUM OR LITHIUM FERRIC FERROUS OXALATE)

After you dissolve 4 grams of ammonium ferric oxalate crystals in 8 ml of distilled water, top the solution off to 10 ml and pour it into a stoppered brown bottle. Add ascorbic acid solution (1% for gold or 2% for palladium and/or platinum) to the bottle of 10ml of 40% ammonium ferric oxalate (or of sodium or lithium ferric oxalate). As I describe repeatedly in my videos and online articles, remember that you have to shake the bottle vigorously -- for 15 to 30 seconds -- to disperse the ferrous iron subsequently created evenly throughout the solution. Otherwise, the ferrous iron will simply precipitate out of solution and fall to the bottom of the bottle: you likely won't get satisfactory results when you attempt to print with a solution of AFFO in that state.

Ruthenium and Iridium:Sources

I have found the best prices for iridium and ruthenium to be had at ArtCraft Chemicals iridum and ruthenium in 5 gram units and Pressure Chemical Company Iridium by the gram and Ruthenium in 10 gram units. Read on to understand why I mention this. Purchase iridium(III) chloride hydrate and ruthenium(III) chloride hydrate. Dissolve directly in distilled water at 20% or less working strength for iridium and 10% or less for ruthenium.

PRINTING WITH IRIDIUM

Iridium is a noble metal of the platinum family. The master printer and photographer Irving Penn frequently mixed iridium with platinum and with palladium for his prints. Based on my results with iridium, I suspect Penn's motivation was to nudge print color toward neutral gray scale and also to deepen the Dmax of his prints. Warning: read the MSDS on iridium and take proper precaution with this metal.

This contact print, on Revere Platinum 140 gsm paper, illustrates the value of iridium as an additive to palladium (or platinum, or gold). The formula was 3 drops of ammonium ferric ferrous oxalate (8 drops 2% C added to a bottle containing 10ml of 40% ammonium ferric oxlate), 2 drops of 26% ferric oxalate (no C added), 3 drops 15% lithium palladium (potassium palladium would work equally well), and 1 drop 5% iridium. The image printed out fully at normal speed (~5 minutes in my 6 13w UV bulb box). It looks like a platinum print with a contrast boost more than palladium. Notice the amazing black of the model's eyes -- that is faithful to the original print.

As this 4x5 contact print shows, iridium is a vigorous medium. It also exhibits slight grain, more so than platinum (at least than the virtually grainless platinum obtained with my Fannintype, in which I use glycerin to constrain the grain). This image was made by mixing 2 drops of 10% iridium with 1 drop of 15% palladium. The sensitizer was 3 drops of ammonium ferric ferrous oxalate, of course, prepared with 8 drops of 2% C. An additional 2 drops of 26% ferric oxalate (no C) boosted the contrast nicely. Clearing was citric acid, water, t-edta, water, t-edta and a final wash. Paper was Bergger Cot 320 sized with gelatin.



I have previously developed out iridium with silver nitrate. The image was strong and vigorous as this one. Because of the grain, however, I expect to keep my use of iridium with palladium, platinum, and gold down to about 25% maximum of total metal solution. Tip: Ruthenium will smooth over any roughness or grain induced by iridium.