Keith,
I have been using carbon black powder from Daniel Smith. Gum bleach development requires higher density negative then normal gum. I would say something more like palladium negative density would be fine to start with. If you can email me a scan of your work I can perhaps troublesoot it.
Marek
> Date: Tue, 1 Jan 2008 19:47:57 -0600 > From: keith.gerling@gmail.com > Subject: Re: direct carbon or gum bleach development > To: alt-photo-process-l@usask.ca > > Hi Marek, > > My attempts look atrocious. What kind of pigment are you using for this? > > thanks! > > Keith > > On Dec 20, 2007 4:05 PM, Keith Gerling <keith.gerling@gmail.com> wrote: > > Awesome, Marek. This is what I want MY prints to look like. Forget > > all that multi-coat nonsense. > > > > > > On Dec 20, 2007 2:28 PM, Marek Matusz <marekmatusz@hotmail.com> wrote: > > > > > > All, > > > 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 > > > > > > http://picasaweb.google.com/marekmatusz1/GumBleachDevelop/photo#5145909559997921266 > > > 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: > > > > > > http://picasaweb.google.com/marekmatusz1/GumBleachDevelop/photo#5145909521343215586 > > > Happy printing > > > Marek > > > > > > > > > ________________________________ > > > Don't get caught with egg on your face. Play Chicktionary! Check it out! > >
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