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Highly Photosensitive Daguerreotypes and their Reproduction: Physico‐chemical Elucidation of Innovative Processes in Photography Developed around 1840 in Vienna
Author(s) -
Ljubić Tobisch Valentina,
Kautek Wolfgang
Publication year - 2019
Publication title -
chempluschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.801
H-Index - 61
ISSN - 2192-6506
DOI - 10.1002/cplu.201900467
Subject(s) - nanoparticle , etching (microfabrication) , halide , colloid , chemistry , latent image , materials science , chemical engineering , nanotechnology , layer (electronics) , organic chemistry , image (mathematics) , engineering , artificial intelligence , computer science
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 Ag 2 O, Ag 2 S, 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 H 2 SO 3 created by the hydrolysis of S 2 Cl 2 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 Na 2 S 2 O 3 . The investigated plate exhibits etched areas with Ag 2 O 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 HNO 3 .