Saponification in egg yolk-based tempera paintings with lead-tin yellow type I
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461446%3A_____%2F19%3AN0000005" target="_blank" >RIV/60461446:_____/19:N0000005 - isvavai.cz</a>
Alternative codes found
RIV/61388980:_____/19:00500939 RIV/60461446:_____/19:N0000007
Result on the web
<a href="https://www.sciencedirect.com/science/article/abs/pii/S1296207418306940?via%3Dihub" target="_blank" >https://www.sciencedirect.com/science/article/abs/pii/S1296207418306940?via%3Dihub</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1016/j.culher.2018.12.004" target="_blank" >10.1016/j.culher.2018.12.004</a>
Alternative languages
Result language
angličtina
Original language name
Saponification in egg yolk-based tempera paintings with lead-tin yellow type I
Original language description
Saponification occurring in paint layers of artworks represents a serious degradation process affecting the appearance and stability of paintings. Formation of metal soaps is mostly reported as a consequence of the interaction of lead white or zinc white with oil binder. We found the distinct symptoms of saponification in paint layers consisting of lead-tin yellow type I and egg yolk binder in a panel painting from the 15th century. This scarce finding induced the study of interactions between lead-tin yellow type I with three different binders: (i) egg yolk tempera, (ii) emulsion of egg yolk and oil, and (iii) oil. The interactions were studied in long-term model experiments using infrared spectroscopy (FTIR) and powder X-ray diffraction (XRD). Based on the results, a set of mixed lead carboxylates of the series Pb(C16)2-x(C18)x, where x = 0, 0.25, 0.5, 0,75, 1, 1.5 and 2, was synthesised as reference materials suitable as a basis for proper identification of neo-formed lead soaps by FTIR and XRD. The formation of lead soaps was detected already within 1 month of reaction in egg yolk containing binders, whereas no soap was formed during 6 months of the experiment in the oil mixture. The neo-formed soaps are various mixed lead carboxylates containing both palmitate (C16) and stearate (C18) in one crystal structure and the proportion of carboxylate anions is affected by the type of the binder. We found the C16:C18 ratio in mixed lead carboxylates is higher in egg yolk tempera samples in accordance with the more abundant palmitic acid in egg yolk fat. On the other hand, the lower C16:C18 ratio in emulsion binder correlates with increased content of stearic acid, suggesting contribution of both binders, i.e. egg yolk and oil, to the soap formation.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10402 - Inorganic and nuclear chemistry
Result continuities
Project
<a href="/en/project/GA17-15621S" target="_blank" >GA17-15621S: Formation of metal soaps in paintings as a cause of their degradation</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2019
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Journal of Cultural Heritage
ISSN
1296-2074
e-ISSN
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Volume of the periodical
38
Issue of the periodical within the volume
JUN (2019)
Country of publishing house
FR - FRANCE
Number of pages
12
Pages from-to
8-19
UT code for WoS article
000471746100002
EID of the result in the Scopus database
2-s2.0-85060291182