Silver Gelatin Developing-Out (DOP), Resin Coated (RC), Photo-Stat

Page Information	Page Information
Date initiated 	January 2012
Contributors 	Amy Brost, Stephanie Watkins
__TOC__
==Silver Gelatin Developing-Out, Resin Coated (RC), Photo-Stat== 
Papers with silver sensitized emulsion layers were used widely for pictorial image making, documentation, and copying processes into the 21st c. Silver-gelatin's market dominance was replaced by digital image technology. Silver-gelatin processes are still used by photographic artists.
=== Historical Facts===
Invented: 1871, Richard Leach Maddox; 1878 improvements, Charles Harper Bennet
Patented:
Important Development Dates: 
* 1874 Commercial production of gelatin for Developing-Out Papers (DOP)
* 1885 Commercial coating machines
* 1894 Baryta layers added to commercial Developing-Out Papers (DOP), 1900 introduced to Kodak papers
Historic and Contemporary Practitioners: As one of the most widely used processes in the 20th c., just about anyone working in this period did work with silver-gelatin at one time or another whether amateur, professional, or copyist. 
=== Identification Characteristics===
==== Image layer====
The image is within the emulsion layer. It can either be partially within the paper structure as with printing-out processes, or on top of a baryta layer as with developing-out processes. 
==== Color====
Pristine silver gelatin printing-out photographs can range in color from warm browns to cool purples because of the nature of the development of the photolytic silver strand. Pristine silver-gelatin developing-out photographs are generally monochromatic, blue-black and white in appearance. Both processes can be toned to different colors with the addition of a toning process during development, using other minerals such as selenium or gold. 
==== Support ====
Silver-gelatin emulsions can be applied to numerous types of substrates including paper. Paper substrates used in direct contact processes are usually sized to withstand the numerous immersion baths required during processing. 
==== Analysis====
===Basic Process Overview===
Image creation in all silver halide processes involves sensitizing a substrate with silver halide, and exposing it to light, which breaks the bond between the silver and the halide. The silver ion is then reduced to become free silver, which creates the dark areas of a photographic image. 
The silver gelatin developing-out process involves exposing and developing a negative, which can be placed into an enlarger. Light is passed through the negative onto sensitized photo paper, which is then chemically developed-out. The exposed paper is developed (to reduce the silver ions), stopped (to stop the reduction/darkening), fixed (to remove the unexposed silver salts), and washed (to remove any trace chemicals from the previous baths).
=== Housing and Storage Considerations===
* Silver gelatin prints should be stored in good quality paper-board folders, to protect from light, dust, and handling. They can also be stored in plastic film folders and sleeves, such as uncoated, unplasticized, virgin polyester terephthalate, poly(ethylene), and poly(propylene). Materials that pass the Photographic Activity Test (P.A.T.) will provide suitable housing for these types of photographs. 
* An ideal temperature and humidity are 68 degrees F (20 degrees C) +/- 2 degree drift and 50% +/-5% variation over 24 hours. 
=== Emergency Recovery===
Handling wet paper can cause damage such as nicks, abrasions, and tearing. Mold can develop on or within the papers and emulsion layers.
=== Other Considerations===
*Moisture and humidity can cause these photographs to attach to themselves and other surfaces. Refer to the Releasing, Detaching, Separating methods section.
*Moisture and humidity, especially if high or sustained, can promote mold growth.
*Gelatin photographs, especially very glossy or ferrotyped surfaces can easily be scratched and marred. 
*Prints may be chromogenic or be hand-colored black-and-white prints.
*Baryta layers may be non-existent, very thinly or thickly applied in both home/boutique-made and commercial made photographic material.
*For Helpful Treatment Techniques, refer to the entirety of the Treatment Procedures listed within the PMCC WIKI.
=== Further Reading===
==== Historic Material====
* Adams, Anselm. 1950. The Print : Contact Printing and Enlarging. New York: Morgan & Morgan.
* Coe, Brian and Mark Haworth-Booth. 1983. A Guide to Early Photographic Processes. London: Victoria and Albert Museum 
* Crawford, William. 1979. The Keepers of Light. New York: Morgan & Morgan. p. 199-212
* Eaton, G. T. 1965. Photographic Chemistry in Black-and-white and Color Photography. Hastings-on-Hudson, N.Y.: Morgan & Morgan.
* Funderburk, Kit. 2007. A Guide to the Surface Characteristics: Kodak Fiber Based Black and White Papers. Rochester, NY: Kit Funderburk self-published
* Gray, G. G. 1987. "From Papyrus to RC Paper: History of Paper Supports." Pioneers of Photography: Their Achievements in Science and Technology. Eugene Ostroff, ed. Springfield, VA, The Society for Imaging Science and Technology: 37-46.
* Hendriks, Klaus B., with Brian Thurgood, Joe Iraci, Brian Lesser, Greg Hill. 1991. Fundamentals of Photograph Conservation: A Study Guide. Toronto, Ontario: Lugus Publications for the National Archives of Canada
* Lavedrine, Bertrand (with Jean-Paul Gandolfo, John McElhone, and Sibylle Monod). 2007 (French version), 2009 (English Version). Photographs of the Past: Process and Preservation. Los Angeles, CA: The Getty Conservation Institute 
* Reilly, James M. 1986. Care and Identification of Nineteenth-Century Photographic Prints. Rochester, NY: Eastman Kodak 
* Wentzel, F. and L. W. Sipley. 1960. Memoirs of a Photochemist. Philadelphia: American Museum of Photography.
* CAMEO: http://cameo.mfa.org
* Funderburk, Kit. "Using Historical Information to Identify and Date Kodak Silver Gelatin Developing-Out-Papers" http://www.nypl.org/audiovideo/using-historical-information-identify-and-date-kodak-silver-gelatin-developing-out-papers
* GEH Notes on Photography (Print): http://notesonphotographs.org/index.php?title=Gelatin_Silver_Print
* Gelatin Silver Print. Victoria and Albert Museum (V&A), "Exploring Photography: Photographic Processes: Gelatin-Silver print." http://www.vam.ac.uk/vastatic/microsites/photography/processframe.php?processid=pr002
* Gelatin Silver Print, WIKIPEDIA, http://en.wikipedia.org/wiki/Gelatin_silver_print/index.php?title=Gelatin_silver_print
* Gelatin Silver Process. WIKIPEDIA. http://en.wikipedia.org/wiki/Gelatin_silver_process
* Kennedy, Nora (moderator). Alison Rossiter, Vera Lutter, and Anne Cartier-Bresson, panelists. "Exploring the Artist's Use of Silver Gelatin Photographs (panel discussion)" http://www.nypl.org/audiovideo/exploring-artists-use-silver-gelatin-photographs
* Messier, Paul. "A Brief History of Silver Gelatin Papers." http://www.nypl.org/audiovideo/brief-history-silver-gelatin-papers-paul-messier
* Weaver, Gawain. 2008. "A Guide to Fiber-Base Gelatin Silver Print Condition and Deterioration" Rochester, NY: Advanced Residency Program at the George Eastman House/International Museum of Photography (GEH/IMP) and Image Permanence Institute/Rochester Institute for Technology (IPI/RIT) http://www.notesonphotographs.org/index.php?title=Weaver,_Gawain._%22Deterioration_of_Fiber-base_Gelatin_Silver_Prints%22
==== Contemporary Practice====
* Alternative Photography (How To): http://www.alternativephotography.com/wp/processes
* Analog Photography Users Group (APUG): http://www.apug.org/forums/home.php
Back to Photographic Materials Main Page
Back to PMG Photographic Processes
Category:Photographic Materials
Category: Photographic Processes