Tag Archives: Bergger COT320

Variations on a theme – Palladium versus Ziatype

Dupont Circle bus stop, Palladium over Fumed Silica
Dupont Circle bus stop, Palladium over Fumed Silica

Here’s another of my 5×12 panoramics of Dupont Circle here in Washington DC. This was several exposures on the same negative, yielding an approximate minute and thirty seconds or thereabouts. We were printing from this negative in my Advanced Topics in Platinum/Palladium Printing class out at Photoworks Glen Echo this past weekend. The print I scanned for this image was printed on Bergger COT320 pre-treated with fumed silica. The fumed silica yields a definite boost in dmax.

The next print is of the same negative, but printed as a Ziatype. Ziatypes are a variation on palladium, but they use either Lithium Palladium or Cesium Palladium and Ammonium Ferric Oxalate instead, which yields a neutral-to-cool tone image more like platinum in color, and they are a printing-out process developed in water as opposed to a develop-out process that requires Potassium Oxalate or Ammonium Citrate as a developer.

The distinction between printing-out and developing-out, in addition to the chemistry variations, is the fact that a printing-out print’s final exposure is judged by visual inspection – what you see when you pull the print from the contact frame is pretty much what you’re going to get when it is washed, cleared, and dried, but a developing-out print will have some kind of ghost image that is anywhere from almost imperceptible to a partial rendition of the final image prior to development. Neither one is better than the other, except that the Ziatype is easier for beginners until they gain confidence in their coating and printing skills. Ziatypes also have a wide range of contrast controls that will also affect image color in addition to contrast.

Dupont Circle bus stop, Ziatype
Dupont Circle bus stop, Ziatype

First print with fumed silica

Here is my first print made with fumed silica as a pre-treatment before coating platinum/palladium. I’m seeing a bit of mottling in the lower left corner which I suspect is from uneven coating. This is on Bergger COT320. 50/50 blend of platinum/palladium, 4 drops 5% Ammonium Dichromate for contrast agent.

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First print from the still-life shoot

Here’s the first print in the wash from the 14×17 still-life shoot I did a week ago. Looking at the negative I was worried it would be too thin to print well in palladium. My fears as you can see were totally unfounded. This was a straight palladium print with 33 drops of Pd, 33 drops of Ferric Oxalate (FeOx), and 2 drops of NA2 (sodium platinum) as a contrast agent. The paper is Bergger COT 320.

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