MSE Seminar Series: Edward P. Vicenzi
Friday, April 20, 2012
1:00 p.m.-2:00 p.m.
Room 2110 Chemical and Nuclear Engineering Bldg.
301 405 5240
An Examination of Nanostructures in 19th Century Daguerreotype Photographs
Edward P. Vicenzi
Museum Conservation Institute, Smithsonian Institution
Surface and Microanalysis Science Division, National Institute of Standards and Technology
In 1839, the Daguerreotype photographic process was first presented to the scientific community in France. The technology spread rapidly and was widely used around the globe until the late 1850s. The formation of the so-called "mirrors with memories" can be generalized in three steps: 1) exposing silver-plated copper to an iodine vapor, 2) further exposing the sensitized plate to visible light within a camera, and 3) development of an image after the plate is treated with heated mercury vapor. The surfaces of these precious images have been the subject of a few microscopy-based studies over the years. However, a detailed examination of the morphology and chemistry at the deep sub-micrometer level has not been undertaken. High resolution images of the Daguerreotype image-forming layer using the FIB-SEM has been employed to visualize the three-dimensional nature of the Ag-Hg nanofilm and any nanoparticles responsible for scattering light on the surface of Daguerreotypes. These cross sections additionally expose the metallographic microstructure of the Ag substrate, especially the layer immediately beneath the image nanofilm for examination and correlation with surface nanostructures.