U of S | Mailing List Archive | alt-photo-process-l | direct carbon or gum bleach development

direct carbon or gum bleach development

More experimentation with gum printing and bleach development.
I was intrigued by Loris's results with using unsized paper. I thought that it would give a rather bad stain. My tricolor gum practice certainly led me to believe this. However on numerous occasions I did observe that edges of paper that I used which did not have gelatin size gave a darker, more uniform black. SO last week I tried to use single sized paper, fresh and unsized  Fabriano Artistico, and a throw away gum print that has been soaked over and over, but had a reverse side of Fabriano paper quite clean. My overall conclusion with this set of prints is that I liked unsized paper and soaked paper best. They gave crispier prints. Perhaps this technique likes the gum to be tied up with the fiber of the paper and the bleach development can give clear paper base. So I would advocate use of straight watercolor paper, no need to size. I have not tried any other brand, but I should have some at hand and will try next printing session.
I have also experimented some more with pigment density. I had a more concentrated carbon stock of 3.75% carbon in 14 baume gum, that is 50% more then in my last set of experiments. The solutions are left over from dozens or maybe hundreds of experiments done in the last two years. Once the water dried out this would result in 3.75/0.27=14% carbon/solid gum mixture (I assume 14 baume gum is 27%). This is definitely black black. Beautiful velvety matte texture of the deep black to take your breath away. Scan of the print here. This print was made on unsized Fabriano Artistico paper 
The mid tones are a little bit darker on this screen that in reality. Maybe even the two tones of black on the very edge are visible. Very outside, had most exposure (I uped the exposure to 6 minutes from last time) and next to it is somewhat lighter edge from exposure through blank part of transparency (Pictorico). This is a further illustration of how a fine tonal gradation can be achieved with this method.
I have also included an detail of the print scanned at 300 dpi:
Happy printing

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