Plasmons, the collective oscillations of mobile electrons in metallic nanostructures, interact strongly with light and produce vivid colors, thus offering a new route to develop color printing technologies with improved durability and material simplicity compared with conventional pigments. Over the last decades, researchers in plasmonics have been devoted to manipulating the characteristics of metallic nanostructures to achieve unique and controlled optical effects. However, before plasmonic nanostructures became a science, they were an art. The invention of the daguerreotype was publicly announced in 1839 and is recognized as the earliest photographic technology that successfully captured an image from a camera, with resolution and clarity that remain impressive even by today’s standards. Here, using a unique combination of daguerreotype artistry and expertise, experimental nanoscale surface analysis, and electromagnetic simulations, we perform a comprehensive analysis of the plasmonic properties of these early photographs, which can be recognized as an example of plasmonic color printing. Despite the large variability in size, morphology, and material composition of the nanostructures on the surface of a daguerreotype, we are able to identify and characterize the general mechanisms that give rise to the optical response of daguerreotypes. Therefore, our results provide valuable knowledge to develop preservation protocols and color printing technologies inspired by past ones.

No abstract

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.

No abstract

No abstract