PROTECTIVE SURFACE COATINGS FOR DAGUERREOTYPES
M. Susan Barger, A.P. Giri, William B. White, William S. Ginell, & Frank Preusser
Barger, M. Susan (1983). “Robert Cornelius and the Science of Daguerreotypy,” in William F.Stapp, Robert Cornelius: Portraits from the Dawn of Photography. Washington, DC: Smithsonian Press, p. 123.
Barger, M. Susan, R.Messier and W.B.White. “Gilding and Sealing Daguerreotypes,” Photographic Science and Engineering27 (1983): 141–146
DaguerreL.J.M. (1839). “Practical description of the process called the Daguerreotype”, (John F. Frazer, trans.) Journal of the Franklin Institute24 (1839): 303–311
Daguerre, L.J.M. “The Daguerreotype”, Journal of the Franklin Institute, 29 (1840): 142
Shoemaker, W.L. “Cleaning the Daguerreotype”, Philadelphia Photographer14 (1877): 233.
“Apparent contrast” and “apparent density” are terms used in connection with daguerreotypes because the appearance of contrast and density in these images is due to light reflectance and scatter, rather than to light absorption. Formally, true optical density is due to light absorption, which does not apply to the daguerreian system. For a more detailed discussion see: Barger, M. Susan, R. Messier, and W.B. White. “A Physical Model for the Daguerreotype,” Photographic Science and Engineering26 (1982): 285–291.
There has been ongoing, extensive research into the material properties and preservation of daguerreotypes at the Materials Research Laboratory of The Pennsylvania State University since 1979. The working collection of some 150 sample daguerreotypes has come from a variety of sources and are chosen because they range over the entire spectrum of daguerreotypes found in collections. Overall, very few of these daguerreotypes have been subjected to destructive testing. All daguerreotypes in the working collection are carefully checked before experimental work is done on them to make sure that no daguerreotypes of historic or aesthetic value are harmed. In addition, close to fifty more daguerreotypes have been submitted for analysis by other institutions and private owners. These daguerreotypes are treated as part of the study, but, of course, are returned to the owners when analyses are completed.
Gorham, W.F. “A New, General Synthetic Method for the Preparation of Linear Poly-pxylylenes”;, Journal of Polymer Science Part A-1, 4 (1966): 3027–3039.
To remove the Parylene C film, a daguerreotype is immersed in hot (165°C) orthodichlorobenzene which converts the film to a gelatinous mass that can be easily removed with gentle swabbing. This process must be carried out in a fume hood that is suitable for handling chlorinated solvents. The toxicity of orthodichlorobenzene is about the same as paradichlorobenzene, a commonly used mothproofing insecticide.
BargerM. Susan, R.Messier and W.B.White, “Nondestructive Assessment of Daguerreotype Image Quality by Diffuse Reflectance Spectroscopy” Studies in Conservation29 (1984): 84–86.
During the deposition of this film, there was an uncontrollable drop in voltage due to a temporary power failure.
R.Messier, personal communication.
Baker, T.E., G.L.Fix and J.S.Judge. “Modified Poly-Paraxylylene Coatings and Films with Improved Oxidation Resistance”, Journal of the Electrochemical Society127 (1980): 1851–1852.
Barger, M. Susan, R.Messier, and W.B.White. “A Physical Model for the Daguerreotype”, Photographic Science and Engineering26 (1982): 285–291