I received a couple of questions about photogravure, some offlist. I haven't seen any websites that go into the details of the process. I've actually registered the domain name photogravure.org and am hoping to put a simple site together as I produce my next round of prints. I've been asked to teach photogravure at Kala in Berkeley next year, probably in March and October, and such a site would help me prepare and be a good resource for the workshop participants as well as the net at large.
It's a complex process, and I am abbreviating it somewhat here. The gelatin sheet, or tissue, comes in large rolls, and can be handled in light. You cut a piece larger than your image, leaving room for the image and a Stouffer 21 step gray scale. You move into a yellow light darkroom situation and sensitize the gelatin sheet in potassium dichromate solution, then squeegee it to something smooth, like plexiglas, for it to dry on. If you do this at the end of the day, it will dry flat and pop off the plexi by morning. In a vacuum table or contact printing frame, you expose a full size positive transparency to the gelatin sheet using a light with a high UV content. After exposure, you put the gelatin sheet into a tray of cool water with your plate and squeegee the sheet to the copper. After a short time, it goes into a tray of warm water, and the paper backing is peeled off, leaving the sensitized gelatin on the plate. Then you mask your image with hard ground, apply the aquatint, and get ready for 40 minutes of etching with up to five different densitities of ferric chloride. I've been told that the best source of information on the process is: Sacilotto, Deli. Photographic Printmaking Techniques. NY: Watson-Guptill, 1982. Hardcover. 215pp. ISBN 0-82304-0062 It's a great book, and I was lucky to find one for under $50. It is a collectors item, and bookfinder.com shows it listed between $200-$600, but perhaps a nearby library would have a copy. There is also: Kolb, Gary P. Photogravure: A Process Handbook. Southern Illinois University Press, 1986. 202pp. ISBN 0-80931-2522 but I have not studied it and have heard that there are either errors or unusual ways of working contained in that book. > Zernike Au writes: > Another method to have photography like > image is photo-etching but this method involve in using poison chemical > and my teacher didn't recommend me to do it, I never have a chance to > try on it. I haven't done it, but photo-etching doesn't produce the same richness in tone. The potassium dichromate used in photogravure is carcinogenic, and is particularly dangerous in its dry form, less so when mixed, so your teacher probably won't let you do photogravure, either. > I am thinking about if it is possible to exposure > the copper plate (for photogravures) directly with my pinhole camera... I've had the same idea, although what you would expose would be the sensitized gelatin sheet, not the plate, and I imagine that the exposure times would be hours long. Are any of your mezzotints available for viewing on the web? I know several collectors here in the Bay Area who collect mezzotints almost exclusively. It is another process with beautiful results. --Eric
