Monitoring the photographic process, degradation and restoration of 21st century Daguerreotypes by wavelength-dispersive X-ray fluorescence spectrometry

Silva, Éric Da; Robinson, Mike; Evans, Christopher A.; Pejović‐Milić, Ana; Heyd, D. V.

doi:10.1039/b913911g

Cited by 16 publications

(17 citation statements)

References 7 publications

(10 reference statements)

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“…on the image surface [1,2,11]. The range of tones on these test plate is representative of 127 the tones observed on historical daguerreian artifacts.…”

mentioning

confidence: 99%

The application of XANES for the examination of silver, gold, mercury, and sulfur on the daguerreotype surface

et al. 2017

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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.

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“…on the image surface [1,2,11]. The range of tones on these test plate is representative of 127 the tones observed on historical daguerreian artifacts.…”

mentioning

confidence: 99%

The application of XANES for the examination of silver, gold, mercury, and sulfur on the daguerreotype surface

et al. 2017

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“…Previous analysis [1][2][3][4][5][6][7][8][9][10][11] has suggested that one possible source of the tarnish could be the deterioration of the cover glass used to protect the daguerreotypes from chemical and/or atmospheric conditions, dust and debris, or from mechanical damage. For example, Barger [12] suggested that deterioration of the cover glass as well as the geometry and composition of the frame might lead to deterioration of daguerreotypes.…”

Section: Introductionmentioning

confidence: 99%

“…The daguerreotype process was used to document individuals and landscapes for approximately 30 years; these images are now important objects of historic significance. The fabrication of daguerreotypes has been previously reported [1,2]. The daguerreian image is the result of reflection and refraction of light off image particles that vary in shape and distribution.…”

Section: Introductionmentioning

confidence: 99%

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Exploring tarnished daguerreotypes with synchrotron light: XRF and μ-XANES analysis

et al. 2018

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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.

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“…Sometimes, when the piece to be cleaned is extremely delicate, the piece can be submitted to alternate cycles of cathodic and anodic cleaning deliberately, to produce a slow release of the adhered oxides. This effect was applied in cleaning daguerreotypes of the nineteenth century (Da Silva et al, 2010), alternating basic (1% w/v sodium metaborate) and acid electrolytes (0.3% w/v citric acid) with current intensity variations and placing the daguerreotype alternatively as anode and cathode. Sometimes electrolytic cleaning produces an irregular cleaning, which mainly affects the so-called "high points", i.e., the most outstanding oxide layers within the topography of the steel probe.…”

Section: Introductionmentioning

confidence: 99%

Optimization of Electrolytic Cleaning of Low Carbon Steels

2015

EJSD

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Electrolysis is an effective method for recovering rusted pieces in acceptable times of operation without generating practically any residues and with a very low cost. The process is controlled by the concentration of electrolyte used, the current intensity selected and the operation time, among others. Knowing the best operating conditions allow cleaning the rusted parts more efficiently. In this work, it was carried out an optimization of the cleaning process by means of an incomplete 33 factorial design. The substrate selected consists of several low steel carbon probes (Fe>99.7%), which were subjected to oxidation in the laboratory to ensure homogeneity. The independent variables assayed included the concentration of the electrolyte employed (x1), the current intensity (x2) and the temperature of operation (x3), whereas the dependent variable was based on the weight differences of the probes after being subjected to the cleaning process. The results obtained showed that the optimal conditions for removing rust from low steel carbon were 5% of electrolyte, a current intensity of 3 A and a temperature of operation of 40 ºC. These results demonstrated the potential application of electrolytic cleaning combined to an optimization by means of a factorial design to restore low steel carbon pieces.

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Monitoring the photographic process, degradation and restoration of 21st century Daguerreotypes by wavelength-dispersive X-ray fluorescence spectrometry

Cited by 16 publications

References 7 publications

The application of XANES for the examination of silver, gold, mercury, and sulfur on the daguerreotype surface

The application of XANES for the examination of silver, gold, mercury, and sulfur on the daguerreotype surface

Exploring tarnished daguerreotypes with synchrotron light: XRF and μ-XANES analysis

Optimization of Electrolytic Cleaning of Low Carbon Steels

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