Microanalysis of Glass Fluid Storage Vials from The Invertebrate Zoology Collection at the National Museum of Natural History

Glass alteration in 19th century glass photographic plates: Potential role in gelatin delamination

“…Museum objects, such as these glass photographic plates, provide a unique opportunity to both visualize, document, and study the development of glass alteration as it has naturally occurred over time. Previous work on alteration observed in glass storage vials in biological specimen collections under aqueous conditions at the Smithsonian and a study at the Library of Congress on the early 19th century glass flutes revealed a similar naturally formed depleted alteration layer by SEM 16,30 …”

“…Previous work on alteration observed in glass storage vials in biological specimen collections under aqueous conditions at the Smithsonian and a study at the Library of Congress on the early 19th century glass flutes revealed a similar naturally formed depleted alteration layer by SEM. 16,30 Although visualizing the depleted alteration layer on these plates was helpful in confirming the altered status of the glass, it also revealed how this alteration is potentially contributing to the delamination of the imagebearing gelatin layer. What is apparent from the SEM images obtained from a fragment of the Muybridge image TA B L E 1 Quantitative scanning electron microscopy-energy-dispersive spectrometry (SEM-EDS) compositions of the lifted altered glass layer and of the underlying bulk glass from the sample shown in Figure 1 plates is that as the gelatin lifted off the glass, it has carried with it a thin layer of glassy material, seen as the bright white line under the delaminated gelatin layer in the BSE image (Figure 1).…”