|Date initiated||March 2022|
Woodburytype[edit | edit source]
Historical Facts[edit | edit source]
A photomechanical process that produces high-quality monochrome images, reproducing the continuous tone of photographs.
Invented: Walter Bentley Woodbury and Joseph Wilson Swan.
Patented: Patented by Walter Bentley Woodbury in 1864.
Identification Characteristics[edit | edit source]
Image layer: Composed of gelatin and pigment. Very stable image material, continuous in tone. Slight image relief can be seen in differential gloss.
Color: Varies according with the pigment used. Any color could theoretically be used to pigment the gelatin, but most prints are black, dark chocolate brown, purple/reddish brown and appear tonally similar to albumen and other POPs.
Support: Mostly found mounted or tipped into books, magazines, or card mounts. Typically cropped flush with the edge of the image area and mounted on a smooth paper support. Can also be mounted to soda lime silicate glass supports for Woodburytype transparencies (lantern slides).
Process Overview[edit | edit source]
A photomechanical process patented by Walter Bentley Woodbury in 1864 and used extensively for high quality book illustrations between 1875 to 1900. Process based on the light sensitivity of dichromated gelatin which becomes hard and insoluble when exposed to light combined with intaglio printmaking.
A dichromate-sensitized sheet of gelatin is exposed to ultraviolet light through a photographic negative. The gelatin hardens to a depth proportional to the amount of exposure. The gelatin layer was then washed in a warm water bath, dissolving the unhardened gelatin, and producing a positive relief image. The gelatin relief was then used to create a lead intaglio printing mold. To create the final print, warm pigmented gelatin was poured into the lead mold and pressed against a smooth sheet of paper. The gelatin adheres firmly to the paper as it cools. Sometimes the surface of the print was coated with collodion or other organic varnishes to help protect the pigment layer and achieve a glossy or matte surface sheen.
Woodburytypes required a special press and ink and could not be printed simultaneously with text. Due to these technical limitations, it was eventually replaced by collotype and halftone photomechanical processes.
Conservation[edit | edit source]
- Stable image material due to the carbon black and other inorganic pigments used.
- Gelatin binder susceptible to cracking or crazing, especially in denser image areas, as true with carbon prints.
- The gelatin binder may be compromised at high temperatures and high humidity due to biological deterioration.
Housing and Storage Considerations[edit | edit source]
- Woodburytypes should be stored in good quality, neutral pH, paper-board folders, to protect from light, dust, and handling.
- An ideal temperature and humidity are 68 degrees F (20 degrees C) +/- 2 degree drift and 50% +/-5% variation over 24 hours.
Exhibition[edit | edit source]
Emergency Recovery[edit | edit source]
- Handling wet paper can cause damage such as image abrasion, nicks, and tearing of the support.
- Mold can develop on or within the papers.
References[edit | edit source]
- George Eastman Museum. 2014. The Woodburytype - Photographic Processes Series - Chapter 9 of 12. Copyrighted 2014, published on YouTube December 12, 2014. Video, 3:34. https://www.youtube.com/watch?v=cOqsaCu-_yw
- Lavedrine, Bertrand, Jean-Paul Gandolfo, John McElhone, and Sibylle Monod. 2009. Woodburytypes (1864-1900). In Photographs of the past: Process and preservation. Translated by John McElhone. France: The Getty Conservation Institute. 176-181.
- Stulik, Dusan, and Art Kaplan. 2013. Woodburytype. The Atlas of Analytical Signatures of Photographic Process and Preservation. Los Angeles, CA: Getty Conservation Institute. https://www.getty.edu/conservation/publications_resources/pdf_publications/pdf/atlas_woodburytype.pdf
- Woodburytype. 2017. Graphic Atlas. Image Permanence Institute, Rochester Institute of Technology. http://www.graphicsatlas.org/identification/?process_id=38
- Woodburytype. n.d. National Portrait Gallery. https://www.npg.org.uk/collections/explore/glossary-of-art-terms/woodburytype
Further Reading[edit | edit source]
|Copyright 2022. Photographic Materials Group Wiki is a publication of the Photographic Materials Group of the American Institute for Conservation. It is published as a convenience for the members of thePhotographic Materials Group. Publication does not endorse nor recommend any treatments, methods, or techniques described herein. Please follow PMG Wiki guidelines for citing PMG Wiki content, keeping in mind that it is a work in progress and is frequently updated.|