In the summer of 1845, under the command of Sir John Franklin, 128 officers and men aboard Royal Navy ships HMS Erebus and HMS Terror sailed into Lancaster Sound and entered the waters of Arctic North America. The goal of this expedition was to complete the discovery of a northwest passage by navigating the uncharted area between Barrow Strait and Simpson Strait. Franklin and his crew spent the first winter at Beechey Island, where three crewmen died and were buried. In September 1846, the ships became stranded in ice off the northwest coast of King William Island, where they remained until April 1848. At that time, the crew, reduced to 105, deserted the ships and retreated south along the island’s western and southern shores in a desperate attempt to reach the mainland and via the Back River, to obtain aid at a Hudson’s Bay Company Post. Sadly, not one individual survived. Previous analyses of bone, hair, and soft tissue samples from expedition remains found that crewmembers’ tissues contained elevated lead (Pb) levels, suggesting that Pb poisoning may have contributed to their demise; however, questions remain regarding the timing and degree of exposure and, ultimately, the extent to which the crewmembers may have been impacted. To address this historical question, we investigated three hypotheses. First, if elevated Pb exposure was experienced by the crew during the expedition, we hypothesized that those sailors who survived longer (King William Island vs. Beechey Island) would exhibit more extensive uptake of Pb in their bones and vice versa. Second, we hypothesized that Pb would be elevated in bone microstructural features forming at or near the time of death compared with older tissue. Finally, if Pb exposure played a significant role in the failure of the expedition we hypothesized that bone samples would exhibit evidence of higher and more sustained uptake of Pb than that of a contemporary comparator naval population from the 19th century. To test these hypotheses, we analyzed bone and dental remains of crew members and compared them against samples derived from the Royal Navy cemetery in Antigua. Synchrotron-based high resolution confocal X-ray fluorescence imaging was employed to visualize Pb distribution within bone and tooth microstructures at the micro scale. The data did not support our first hypothesis as Pb distribution within the samples from the two different sites was similar. Evidence of Pb within skeletal microstructural features formed near the time of death lent support to our second hypothesis but consistent evidence of a marked elevation in Pb levels was lacking. Finally, the comparative analysis with the Antigua samples did not support the hypothesis that the Franklin sailors were exposed to an unusually high level of Pb for the time period. Taken all together our skeletal microstructural results do not support the conclusion that Pb played a pivotal role in the loss of Franklin and his crew.

We report on the elemental and chemical characterization of tarnish on a historic daguerreotype plate. Scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) spectroscopy reveal the presence of C, O, Na, K, P, Cl, Hg, Ag, Cu, S and Au. Synchrotron based X-ray absorption near edge structure (XANES) spectroscopy, together with two-dimensional X-ray fluorescence (XRF) microscopy, provide information beyond the elemental distribution and speciation of the daguerreian tarnish features, revealing the presence of NaCl, KCl, HgCl 2 , HgSO 4 , CuS, and Ag 2 S on the surface. Through the application of synchrotron XRF, the distributions of Ag and S were found to be inversely correlated. This suggests a preferential accumulation of S within high-density particle regions. Spectroscopic investigation at different regions within the XRF image showed that blemish regions contained degradation products such as NaCl and KCl with AgCl noted in the surrounding regions. The observation of Cu on the surface, in the form of CuS, may either be a result of Cu diffusing through grain boundaries and/or holes in the Ag, or from the accretion of Cu salts, such as basic sodium copper carbonate, from the deterioration of the above cover glass. Silver halides (AgCl, AgBr and AgI) were also detected with XANES. This may be the result of either environmental conditions or from residual products from the production process of the plate. These results point to the interaction between deterioration products from the cover glass with the daguerreotype surface as one, but not the only, source of the tarnish.

X-ray absorption near edge structure (XANES) spectroscopy was used to study a freshly prepared reference daguerreotype surface as the first step in devising improved methods for the conservation of these important historic artifacts. The results are consistent with the formation of alloy image particles. Interdiffusion of gold and silver has led to the development of a silver–gold alloy; the composition varies with depth. The amount of gold appeared to be elevated in the highlighted regions of the image, whereas shadow regions have lower levels of gold on the surface. The apparent increase in gold within the highlighted region may be due to the larger surface area presented by an array of small image particles. The mercury used to develop the daguerreian image showed no evidence of oxidation while a mercury–silver alloy was detected. Sulfur-based contaminants are also detected. The implications of these findings are discussed.

A daguerreotype image, the first commercialized photographic process, is composed of silver-mercury, and often silver-mercury-gold amalgam particles on the surface of a silver-coated copper plate. Specular and diffuse reflectance of light from these image particles produces the range of gray tones that typify these 19th century images. By mapping the mercury distribution with rapid-scanning, synchrotron-based micro-X-ray fluorescence (μ-XRF) imaging, full portraits, which to the naked eye are obscured entirely by extensive corrosion, can be retrieved in a non-invasive, non-contact, and non-destructive manner. This work furthers the chemical understanding regarding the production of these images and suggests that mercury is retained in the image particles despite surface degradation. Most importantly, μ-XRF imaging provides curators with an image recovery method for degraded daguerreotypes, even if the artifact’s condition is beyond traditional conservation treatments.

Louis‐Jacques‐Mandé Daguerre introduced the first successful photographic process, the daguerreotype, in 1839. Tarnished regions on daguerreotypes supplied by the National Gallery of Canada were examined using scanning electron microscopy energy‐dispersive X‐ray spectroscopy and synchrotron‐radiation analysis. Synchrotron X‐ray fluorescence imaging visualized the distribution of sulfur and chlorine, two primary tarnish contributors, and showed that they were associated with the distribution of image particles on the surface. X‐ray absorption near‐edge structure spectroscopy determined the tarnish to be primarily composed of AgCl and Ag2S. Au2S, Au2SO4, HAuCl4 and HgSO4 were also observed to be minor contributors. Environmental contamination may be a source of these degradation compounds. Implications of these findings will be discussed.