Stabilization of Verdigris

Hofmann, Christa; Härtl, Andreas; Ahn, Kyujin; Druceikaite, Kristina; Henniges, Ute; Potthast, Antje

doi:10.1080/18680860.2016.1247515

Cited by 7 publications

(7 citation statements)

References 6 publications

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“…In what concerns the conservation of this cultural heritage, the use of verdigris on paper raises great concern since its degradation corrodes the organic support, similarly to iron gall inks. Additionally, the changes in color from green to dark brown greatly affect our perception of the artworks [15]. While there has been much research on treatments for stabilizing iron gall inks' degradation [16], there is still much to be learned on copper acetate degradation [15,17,18].…”

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confidence: 99%

New Insights into Synthetic Copper Greens: The Search for Specific Signatures by Raman and Infrared Spectroscopy for Their Characterization in Medieval Artworks

2019

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A systematic investigation of medieval copper green pigments was carried out based on written sources: 21 manuscripts, dating from 50-70 to 1755 AD, were sourced and 77 recipes were selected, translating into 44 experiments. Reconstructions from medieval recipes were prepared and characterized through a multianalytical approach to disclose the original pigment formulation that is often described as verdigris. Based on the results obtained, we propose three main groups of copper green pigments, group 1, in which only Cu(CH 3 COO) 2 ·H 2 O is formed; group 2, where this acetate is found together with copper oxalates; group 3, in which atacamite is present as the major green component or as a signature compound. The products formed are in perfect agreement with that predicted by the state-of-the-art research on the mechanisms of atmospheric corrosion of copper. This knowledge, together with our experience on craft recipes to prepare medieval paint materials, allowed us to recover a lost medieval recipe to produce a copper green pigment based mainly on atacamite, a basic copper chloride, which has been recently detected, by Raman and infrared spectroscopy, in artworks ranging from Catalonia and the Crown of Aragon panel painting to Islamic manuscripts.

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confidence: 99%

New Insights into Synthetic Copper Greens: The Search for Specific Signatures by Raman and Infrared Spectroscopy for Their Characterization in Medieval Artworks

2019

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“…The deleterious effects of copper-containing species with paper have been the focus of attention for paper conservators and heritage conservation scientists alike; however, in contrast to our research, the research has been heavily focused on treatment development and evaluation. 4,8,44,48,49 While there are several established chemical structures for Cu(II) acetates or verdigris, the present study documented that two starting species (basic and neutral) will transform into a different verdigris species, the intermediate Cu(CH 3 COO) 2 • 3Cu(OH) 2 •2H 2 O during their degradation, as pigment, and in the presence of cellulose. This species has been documented previously, but the impact of other common constituent documents (gum arabic) has not been well-documented.…”

Section: Resultsmentioning

confidence: 53%

“…These two verdigris species represent two possible starting materials used by artists for their different coloring. 13,28,43–45…”

Section: Resultsmentioning

confidence: 99%

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Multi-Analytical Study of Copper-Based Historic Pigments and their Alteration Products

et al. 2019

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Copper-containing materials such as verdigris are commonly found in historic and artistic works of art, often at advanced states of decay. Applied on paper as inks and watercolors, many of which needed a binder such as gum arabic, the intrinsic instability of this pigment was known since the medieval period. The decay of verdigris (a mixture of copper acetates) as a pigment, as watercolor, and as a dye, was studied using a combination of vibrational (Fourier transform infrared) and X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) instrumental techniques. Changes in the copper oxidative states and the formation of copper oxide were monitored during accelerated degradation as powdered solids and applied on mockup samples (with and without binder). Accelerated aging of both commercially available and synthesized verdigris pigments showed the presence of an intermediate species, Cu(CH3COO)2•3Cu(OH)2•2H2O, which points to the beginning of the decay processes, that culminates in the formation of Cu(II) oxide. However, the presence of gum arabic seems to delay deterioration, by temporarily reducing Cu(II) to Cu(I), even when the final product includes Cu(II). This novel application of XPS and supporting techniques has significant implications in art conservation, as the identified behavior helps explain the better preservation state of some works of art.

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“…29 The pigment was easily available to artists for centuries and is found in manuscripts, printed books, maps, and fine art. 30 Verdigris is known to damage cellulose-the molecular component of paper-in several stages. Damage starts with colour changes (going from bright green-blue to dull brown) and bleeding, then progresses to degradation and destruction of both media and substrate.…”

Section: Conservation Reportmentioning

confidence: 99%

An Illustrated Shiʿi Pilgrimage Scroll in the Collections of the Royal Asiatic Society

Marzolph¹,

Renauld²

2021

JRAS

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The collections of the Royal Asiatic Society hold an illustrated pilgrimage scroll apparently dating from the first half of the nineteenth century. The scroll's hand painted images relate to the journey that a pious Shiʿi Muslim would have undertaken after the performance of the pilgrimage to Mecca. Its visual narrative continues, first to Medina and then to the Shiʿi sanctuaries in present-day Iraq, concluding in the Iranian city of Mashhad at the sanctuary of the eighth imam of the Twelver-Shiʿi creed, imam Riḍā (d. 818). The scroll was likely prepared in the early nineteenth century and acquired by the Royal Asiatic Society from its unknown previous owner sometime after 1857. In terms of chronology the pilgrimage scroll fits neatly into the period between the Niebuhr scroll, bought in Karbala in 1765, and a lithographed item most likely dating from the latter half of the nineteenth century, both of which depict a corresponding journey. The present essay's initial survey of the scroll's visual dimension, by Ulrich Marzolph, adds hitherto unknown details to the history of similar objects. The concluding report, by Mathilde Renauld, sheds light on the scroll's material condition and the difficulties encountered during the object's conservation and their solution.

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Stabilization of Verdigris

Cited by 7 publications

References 6 publications

New Insights into Synthetic Copper Greens: The Search for Specific Signatures by Raman and Infrared Spectroscopy for Their Characterization in Medieval Artworks

New Insights into Synthetic Copper Greens: The Search for Specific Signatures by Raman and Infrared Spectroscopy for Their Characterization in Medieval Artworks

Multi-Analytical Study of Copper-Based Historic Pigments and their Alteration Products

An Illustrated Shiʿi Pilgrimage Scroll in the Collections of the Royal Asiatic Society

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