Platinum-palladium Printing with Digital Negatives - Sept 10-11
taught by Clay Harmon
This class is an introduction to the platinum-palladium printing process. This particular alternative photographic printing process was invented in the 1870’s by William Willis. Because the process precipitates a chemically non-reactive noble metal into the paper fibers, it creates a print notable both for its permanence and its beauty. In the early 20th century, the process was widely considered the ultimate in photographic printing quality until World War I increased the cost of platinum and palladium and made it economically prohibitive.
The beauty of the platinum-palladium print is in the subtle gradation of tones from dark to light. Platinum-palladium prints are prized for their ethereally subtle highlight tonality. Even though platinum and palladium are still expensive metals to use for making photographic prints, the modern use of digitally printed negatives minimizes the cost to a great degree.
The process involves mixing a UV light sensitive solution of ferric oxalate with a solution of sodium or lithium chloropalladite which is then coated onto the paper with a soft brush. The coated paper is allowed to dry and then sandwiched with a negative and printed using an intense UV light source. It is then processed by submerging the exposed print in a developer solution of potasssium oxalate. After development, the print is passed through a series of three clearing baths which remove the residual ferric oxalate sensitizer. After clearing, the photographic image is a permanent combination of microscopically fine palladium particles embedded in the paper fibers.
This workshop is appropriate for anyone interested in learning one of the easiest and most rewarding alternative printing techniques. Because we will be printing on art paper, this process presents another type of visual content that can be included in books and other similar projects. The student will only need some digital image files to print.
The workshop fee includes a $100 materials charge that will supply the student with enough chemistry and paper to make about 10-12 8×10 images on 11×14 sheets of paper. Workshop participants will be asked to submit approximately a dozen 5×7 to 8×10 (360dpi) images to an online folder one week prior to the class so that the first few negatives will be ready to go when the class begins.
What is covered in the class:
- evaluation of the image and preparation for printing the negative in Photoshop
- brief overview of the use of Quadtone RIP to make a digital negative on transparency film
- paper selection criteria
- procedure to test for the proper exposure time for the digital negative
- coating techniques for various papers
- print development and processing
- troubleshooting print problems
- spotting and finishing prints
Hahnemehule Paper is a generous sponsor of our workshops and will supply the wonderful Hahnemeuhle Platinum Rag and Hahnemeuhle Etching papers. Check out their range of papers at their website.