The properties of light-scattering metallic nanoparticles on the surface of daguerreotypes affect image characteristics such as color, a study finds. The daguerreotype is among the earliest photographic technologies to successfully capture an image from a camera, with extraordinary resolution and clarity even by current standards. The preservation of daguerreotypes, which are records of history and culture, requires an understanding of the physical and chemical mechanisms underlying their optical response. Alejandro Manjavacas and colleagues combined daguerreotype artistry and expertise, experimental nanoscale surface analysis, and electromagnetic simulations to perform a comprehensive analysis of these early photographs. The findings showed that the scattering spectrum of individual nanoparticles on the daguerreotype surface consists of a narrow, blue/UV peak as well as a broader red peak. As a result, the daguerreotype exhibits a blue tone when viewed from above, but the tone shifts to brown/red as the viewing angle increases. Moreover, the scattering spectrum of the nanostructure is strongly affected by particle morphology and size, but not composition. For example, decreasing nanoparticle height leads to a blueshift in the spectrum, whereas increasing overall nanoparticle dimensions causes a redshift and broadening of the spectral peak and diminishes the angle-dependent color effect. According to the authors, these insights could be used to develop preservation protocols and novel color printing technologies.
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Article #19-04331: "Nineteenth-century nanotechnology: The plasmonic properties of daguerreotypes," by Andrea Schlather, Paul Gieri, Mike Robinson, Silvia Centeno, and Alejandro Manjavacas
MEDIA CONTACTS: Alejandro Manjavacas, University of New Mexico, Albuquerque, NM; tel: 505-277-1064; e-mail: < manjavacas@unm.edu >
Proceedings of the National Academy of Sciences