"Datura Blooms II" ~ Palladium Print
The second of the Datura Blooms images, and the one that will be on the cover of the book I am currently writing, on palladium printing, with a section on the double sodium (Na2) process. For now, I am working with palladium, working out the best light source ~ density range, for the negative. The two Datura Blooms prints were made in the UV printer, both negatives with little in the way of increased densities overall. The success of these two prints was the fact there was precious little middle tones involved. The majority of the tonal spectrum was black & white, thereby needing little in the way of tonal control, beyond controlling the whites; print time/developer temperature.
Although these two prints had a print time of 15 minutes in the UV printer [160W UV @ 365nm) the other images I've been testing the past two weeks have proven to require really ling print times; beyond 20 minutes. That is why I've returned to using the sun, although I am working out a means of a more steady print light source, than north light, or even reflected (bounced) light. I will have more to say on that later, when I have more fully tested it. The single test done today indicates that using a defuser plate, such as a 3/16" white opaque plexiglass sheet over the print frame, in full sunlight adds approximately 30% to the print time, all other variables constant.
The negatives printed for the UV printer have been about Log .8, which is a mostly a very good fit. I will now add a Palladium <curve> I created to boost the negatives approximately 40%-50%, boosting them to the range of printing in direct sunlight, with a print time between 7-9 minutes, which is a good range for controlling the printing. The tests have also been very instructive in the visual differences in print imagery by altering the temperature of the developer, as well as choosing a warm toned or cool toned developer. Some iamges are enhanced by cool tones, some warm tones. The image I'm working on now is the "Blue Goose" train, now no longer in service. An historical train on the Oregon coastal range. That print, when done, will become a gum over palladium print.
This palladium print was printed in my UV printer; 15 minutes. Developed in potassium oxalate at 85 degs F. Printed on Revere Platinum paper. The warm tone of the heated oxalate is more pronounced in the print.
"Datura Blooms II" ~ 8x10 ~ 1/3
Sonoran Desert, Arizona