Highly Photosensitive Daguerreotypes and their Reproduction: Physico‐chemical Elucidation of Innovative Processes in Photography Developed around 1840 in Vienna

Abstract

A physico‐chemical elucidation of the first photographic technology that allowed manifold reproduction is presented. An etched daguerreotype manufactured around 1840 in Vienna, preserved by the Technisches Museum Wien, served as a case study. Surface analysis showed that the photographic process involved the formation of colloidal Ag nanoparticles with sizes of 30–120 nm with shell layers consisting of Ag2O, Ag2S, and some AgCl. This breakthrough photographic technique provided a hitherto unachieved high sensitivity because of various halogenide mixtures without the use of Hg. The image development consisted of the reduction of the Ag halides by H2SO3 created by the hydrolysis of S2Cl2 leading to the formation of Ag nanoparticles adjacent to the Ag nuclei of the latent image. The fixing of the image was performed either by KCN or by Na2S2O3. The investigated plate exhibits etched areas with Ag2O conversion layers and no Cl or S. The gum arabic use for etching preferentially wetted the exposed Ag nanoparticle regions so that unexposed areas could be etched by HNO3.

Die chemische Wirkung des Lichts und die frühe Kunst der Fotografie

“…[2][3][4] Auch in Wien erforschten und implementierten stark interdisziplinär ausgerichtete Kreise von Akademikern, Kaufleuten, Handwerkern und Künstlern beide Techniken. [5][6][7] Sie übernahmen zu dieser Zeit eine führende Rolle in Europa und weltweit durch die gegenseitige Nutzung von Wissen und Ressourcen: Bahnbrechend war beispielsweise die Metallkamera (Abbildung 1), welche die Wiener Optikerfamilie Voigtländer auf Grundlage des ersten mathematisch be-…”

“…Die ersten Untersuchungen zeigten in den unbelichteten Bereichen geätzte Profile bis 6 μm Tiefe, mit Ätzgruben von 200 bis 400 nm Durchmesser (Abbildung 5 oben). 6,7) In den belichteten Zonen entstanden Silbernanopartikel mit Durchmessern von 30 bis 120 nm (Abbildung 5 unten).…”

“…Die Wiener Erfinder aber kamen ohne Quecksilber als Entwickler aus, was zeigt, wie einzigartig ihr fotografischer Ansatz im Gegensatz zur klassischen Daguerreotypie war (Tabelle 1). 6) Abb. 5.…”

The Degradation of Daguerreotypes and the Relationship with Their Multi-Material Structure: A Multimodal Investigation

“…The process to realize a daguerreotype-contrived by Niépce and Daguerre and later modified to improve its effectiveness-consists of several steps summarized in Figure 1a [2][3][4][5]. The image particles, with a nanoscale dimension, are formed over the copper-silver plate.…”

“…However, the size of the plate or the invasiveness (required physical sampling) might limit their application. The microscopic investigations shed light on the image particle formation, on their shape, and how their modifications impact the optical properties of the daguerreotype [3,5,6]. Additionally, elemental spot sensing with X-ray fluorescence (XRF) [10] and Laser-Induced Breakdown Spectroscopy (LIBS) [17] proved particularly useful due to the prevalence of the metallic and glass elements inside the daguerreotypes structures; however, the latter is micro-invasive.…”