Hi all.
I'm really interested in the chiba system in as much as it seems to allow thicker relief prints.
Ultimately I would like to print white on black using chalk (English whiting) instead of carbon/ink. I would also like to have as much relief as is physically possible. I'd love to get 2mm or more in the final dry print.
Nothing in the chiba paper implies this is possible but hey we can but dream.
Any ideas?
ThanksGreg, Sandy King has written quite a bit about ferric carbon (similar to Chiba) in the carbon transfer group on groups.io. You should take a look.
With regards relief, it can be a beautiful effect. I recently made a traditional carbon print with thick tissue, and the result is dramatic. I wish you good luck with your research.
Ok thanks for that info.The dichromate gets all the way through the gelatin. (It's easy to tell; an overexposed carbon tissue hardens all the way through.) As for thickness, it's a bit less than the unexposed tissue, which was 2mm thick wet, and maybe .15mm dry. So maybe .12 or .11mm.
What matters for maximum thickness is how high it's poured. The carbon group has at least one thread about very tick tissue, and it sounds challenging, but doable.
Another process to look up is the Woodburytype. It was based entirely on high relief gelatin.
Yes the whiting chalk is very dense so I will start with it very dilute.I will affirm that the sensitizer does penetrate all the way through thick layers of gelatin.
I pour at a rate of 1.2 ml of 'glop' per square inch and use lampblack watercolor paint as my main pigment source. I use a minimum of pigment in order to achieve the greatest possible relief (all other factors being the same). While tissue thickness is a major consideration in achieving a raised relief, it is not the determining factor (unless it is not thick enough). Relief will be determined by the depth into the gelatin to which one can harden the tissue. If your white pigment is too opaque to UV light at the concentration you have in your glop, then you may not be able to expose far enough into the gelatin to get significant relief.
This holds true for all pigments. When I was learning the process on my own, I slowly reduced the pigment load and found I was getting more relief. I also had to change the characteristics of my negatives and sensitizing concentration to match the new tissue. I found myself aiming at a method that gave me the longest exposure times to allow the UV to penetrate deep into the gelatin through the clear areas of the negative (my Zone 0s), yet have the density range to reproduce all the finer highlight values with the sensitizer concentration I was using. These will be the sort of factors you will be juggling to make your own image. Gelatin concentration is another factor, with more relief possible with higher concentrations.
Haha yes well that is not my only intended audience.I have thought often about the type of project you are embarking on..both the audience, and using white pigment. While black pigment would be more straight forward (and perhaps an easier way to learn the process), white pigment is an interesting artistic choice, but I wonder at it's significance to your audience (which is probably wider than the seeing-impaired). If you have not, I also suggest researching into the optimium height of the relief. 2mm might be an excessive goal.
Thanks VaughnThicker tissues require longer drying times when poured and when sensitized. Handling a freshly poured 14"x17" tissue of 290ml of wet set glop, there is quite a bit of heft to it. With a fan for the first 12 hours, I like to have the tissue dry for 48 hrs before use.
Good luck!
Yeah it is cool. It is going to be cool to finally do it and see what people say.The possibilities are exciting. A facial portrait made almost life size. A blind person could go back and forth between the carbon print and the person's face and give feedback on the tactile accuracy.
I do not understand what you mean be this...how will it be significantly different that a carbon print made with black ink -- except for the highlights will be raised instead of the blacks? Which is interesting enough!...
Using White on black would add to the effect if the subject was lit just off directly in front.
Yes that is my point. Thus the focus is on the highlights not the shadows.I do not understand what you mean be this...how will it be significantly different that a carbon print made with black ink -- except for the highlights will be raised instead of the blacks? Which is interesting enough!
People who have been blind since birth will treat these image far differently than the sighted. The sighted do tend to think as black shadows areas as 'holes'...our language reinforces this. We say how wonderfully deep those blacks are in a print. brillient highlights and deep blacks. The blind will ' see' these completely differently...they will not reference things as to the qualities of brightness and darkness.
It will be far easier to build up relief if you use no pigment at all. The blind certainly do not need it.
Edit: PS -- even without pigment there will be a slight image due to the darkening of the exposed gelatin. There is the option below, but not quite as neat as an analog approach...and the possibility of very fine detail to challenge the tactile sense. A 3D printer for this use would be boardering on scultpture.
No connection -- just a google find: https://see3d.org/
I think you should test the concept with help from a blind person before you go further. Maybe with a 3D print or something else easy to obtain. I'm skeptical that smoother transitions in tone that relate to gentle slopes in the profile will be noticeable. It might only work for high contrast, relatively sharp edged subject matter.
Thanks VaughnGoing from a dry pigment source, to a finely ground pigment, to a well dispersed mix w/ gum arabic or similar, and finally well dispersed in one's glop is quite an involved process for those so inclined. I am quite happy with watercolor paint in tubes so that I only have to deal with that last step...and so many variables avoided!
Sandy put me onto a post in groups.io where he suggests simply increasing the solids and halving the pigment in the mix https://groups.io/g/carbon/topic/how_to_make_extra_thick/70112551?p=,,,20,0,0,0::recentpostdate%2Fsticky,,,20,2,180,70112551#I work with thick tissues using the minimum of pigment to create a black at a semi-reasonable exposure time (and to help with relief). At this low level, slight changes in pigment concentration create large changes in the qualities of the tissue (and thus the print). I need to be pretty tight on that. For example my usual grams of lampblack watercolor pigment for 750 ml of water would be 4.5 grams, with 0.5 gram of Burnt Sienna for a little warmth.
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