Laser Ablation Mass Spectroscopy of Nineteenth Century Daguerreotypes

Abstract

Laser desorption mass spectroscopy has been used to characterize both modern and ∼ 150-year-old daguerreotypes. Such investigations are a necessary prelude to attempts to clean them of tarnish and other contaminants by laser ablation of the surface layers. Both positive- and negative-ion time-of-flight spectra were obtained following YAG laser ablation/desorption at 1064, 532, and 355 nm. Major peaks obtained from several daguerreotypes reveal expected elements from the substrate (Ag, Cu) as well as the developing (Hg) and gilding (Au) processes. Silver clusters (Agn) may reflect surface desorption of molecules or, alternatively, aggregates formed in the ejection process. Silver sulfide molecules observed from old daguerreotypes are the signature of the tarnishing process.

A multispectroscopic structural study of lead silicate glasses over an extended range of compositions

“…This plume is the result of the molecular species being removed from the surface creating a ''plasma cloud" above the sample face. If the density of the plume is high enough, it can lead to gas phase reactions [8] and thus the peaks of the resulting spectra will no longer truly represent the glass composition, though this kind of higher-power arrangement is often [9][10][11][12][13] used for elemental analysis. We never saw visual evidence of a plume, and we also note that such a plume would drastically alter the resolution of our instrument, a phenomenon which was never observed.…”

Nineteenth-century nanotechnology: The plasmonic properties of daguerreotypes

“…and compared with the number of daguerreotypes reported to have been produced in the 19th century, only a relatively small number of plates have been examined beyond conventional optical microscopy with spectroscopic techniques, scanning electron microscopy (SEM), and other nanoscale imaging methods capable of examining and characterizing the nanostructures on their surface (6,(36)(37)(38)(39)(40)(41)(42)(43)(44)(45)(46)(47). Unfortunately, time and exposure to the elements have irreversibly altered 19th-century daguerreotype images, making it difficult to use them to characterize their properties.…”

Exploring tarnished daguerreotypes with synchrotron light: XRF and μ-XANES analysis

“…Sulfur and chlorine are the two elements with the greatest association with daguerreotype image deterioration in the forms of silver sulfide [5] and silver chloride [6], respectively. Several analytical techniques [3,[7][8][9][10] have been used to further the understanding of the tarnish composition for conservation, preservation, storage, and display of these artifacts. Currently, there is no clear explanation for the origin of tarnish features, nor is there a consensus on the most effective conservation technique.…”

“…Previous analysis [1][2][3][4][5][6][7][8][9][10][11] has suggested that one possible source of the tarnish could be the deterioration of the cover glass used to protect the daguerreotypes from chemical and/or atmospheric conditions, dust and debris, or from mechanical damage. For example, Barger [12] suggested that deterioration of the cover glass as well as the geometry and composition of the frame might lead to deterioration of daguerreotypes.…”