Selective Dating of Paint Components: Radiocarbon Dating of Lead White Pigment

ABSTRACTLead white is a man-made white pigment commonly used in works of art. In this study, the possibility of radiocarbon dating lead white pigments alone and in oil paints was explored using well-dated lead white pigments and paints. Resulting14C ages on lead white pigments produced following the traditional stack process, where carbonate groups results from the incorporation of CO2originating from fermentation, matched the production years, while radiocarbon dating of lead white made using other industrial processes indicate that14C depleted CO2was used in their production. The method was applied to two case studies, where lead carbonate samples were dated in two oil paintings, one Baroque and one from the 20th century. We hereby show that the lead white pigment can be dated by14C and used as proxy for the time of creation of an artwork. Additionally, a two-step method was developed to allow14C analysis of both the lead white pigment and oil binder from the same sample. A single lead white paint sample can yield two distinct radiocarbon ages, one from the carbonate and one from the natural organic binder. This study thus proposes new strategies for14C dating of artworks.

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Radiocarbon dating of lead white: novel application in the study of polychrome sculpture

Scientific Reports ◽

10.1038/s41598-021-91814-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Sara Sá ◽

Laura Hendriks ◽

Isabel Pombo Cardoso ◽

Irka Hajdas

Keyword(s):

Radiocarbon Dating ◽

Lead White ◽

Human History ◽

White Pigment ◽

Multidisciplinary Study ◽

Paint Systems ◽

Technological Advances ◽

Polychrome Sculpture ◽

Cultural Heritage Objects ◽

Source Of Information

AbstractRecently, radiocarbon dating underwent considerable technological advances allowing unprecedented sample size downscaling. These achievements introduced novel opportunities in dating cultural heritage objects. Within this pioneering research, the possibility of a direct 14C dating of lead white pigment and organic binder in paint samples was investigated on polychrome sculptures, a foremost artistic expression in human history. The polychromy, an indivisible part of polychrome sculpture, holds a key role in the interpretation and understanding of these artworks. Unlike in other painted artworks, the study of polychromies is repeatedly hampered by repaints and degradation. The omnipresence of lead white within the original polychromy was thus pursued as dating proxy. Thermal decomposition allowed bypassing geologic carbonate interferences caused by the object's support material, while an added solvent extraction successfully removed conservation products. This radiocarbon dating survey of the polychromy from 16 Portuguese medieval limestone sculptures confirmed that some were produced within the proposed chronologies while others were revised. Within this multidisciplinary study, the potential of radiocarbon dating as a complementary source of information about these complex paint systems guiding their interpretation is demonstrated. The challenges of this innovative approach are highlighted and improvements on sampling and sample preparation are discussed.

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Macroscopic x-ray powder diffraction imaging reveals Vermeer’s discriminating use of lead white pigments in Girl with a Pearl Earring

Science Advances ◽

10.1126/sciadv.aax1975 ◽

2019 ◽

Vol 5 (8) ◽

pp. eaax1975 ◽

Cited By ~ 8

Author(s):

S. De Meyer ◽

F. Vanmeert ◽

R. Vertongen ◽

A. Van Loon ◽

V. Gonzalez ◽

...

Keyword(s):

Optical Properties ◽

Powder Diffraction ◽

Lead White ◽

White Pigment ◽

Microscopic Scale ◽

X Ray ◽

Oil Paintings ◽

Johannes Vermeer ◽

Diffraction Imaging ◽

The 19Th Century

Until the 19th century, lead white was the most important white pigment used in oil paintings. Lead white is typically composed of two crystalline lead carbonates: hydrocerussite [2PbCO3·Pb(OH)2] and cerussite (PbCO3). Depending on the ratio between hydrocerussite and cerussite, lead white can be classified into different subtypes, each with different optical properties. Current methods to investigate and differentiate between lead white subtypes involve invasive sampling on a microscopic scale, introducing problems of paint damage and representativeness. In this study, a 17th century painting Girl with a Pearl Earring (by Johannes Vermeer, c. 1665, collection of the Mauritshuis, NL) was analyzed with a recently developed mobile and noninvasive macroscopic x-ray powder diffraction (MA-XRPD) scanner within the project Girl in the Spotlight. Four different subtypes of lead white were identified using XRPD imaging at the macroscopic and microscopic scale, implying that Vermeer was highly discriminatory in his use of lead white.

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On metal and ‘spoiled’ wine: analysing psimythion (synthetic cerussite) pellets (5th–3rd centuries BCE) and hypothesising gas-metal reactions over a fermenting liquid within a Greek pot

Archaeological and Anthropological Sciences ◽

10.1007/s12520-020-01184-1 ◽

2020 ◽

Vol 12 (10) ◽

Author(s):

E. Photos-Jones ◽

P. Bots ◽

E. Oikonomou ◽

A. Hamilton ◽

C. W. Knapp

Keyword(s):

Early Period ◽

Mineralogical Composition ◽

Acetic Acid Bacteria ◽

Lead White ◽

Lead Carbonate ◽

White Pigment ◽

Metallic Trace Elements ◽

Basic Lead Carbonate ◽

Key Drivers ◽

Greek World

Abstract A Pb-based synthetic mineral referred to as psimythion (pl. psimythia) was manufactured in the Greek world at least since the 6th c BCE and routinely by the 4th c BCE. Theophrastus (On Stones, 56) describes its preparation from metallic Pb suspended over a fermenting liquid. Psimythion is considered the precursor of one of western art’s most prominent white pigments, i.e. lead white (basic lead carbonate or synthetic hydrocerussite). However, so far, and for that early period, published analyses of psimythia suggest that they consisted primarily of synthetic cerussite. In this paper, we set out to investigate how it was possible to manufacture pure cerussite, to the near exclusion of other phases. We examined the chemical and mineralogical composition (pXRF/XRD) of a small number of psimythion pellets found within ceramic pots (pyxis) from Athens and Boeotia (5th–4th c BCE) in the collection of the National Archaeological Museum (NAM), Athens. Analyses showed that the NAM pellets consisted primarily of Pb/cerussite with small amounts of Ca (some samples) and a host of metallic trace elements. We highlight the reference in the Theophrastus text to ‘spoiled wine’ (oxos), rather than ‘vinegar’, as has been previously assumed, the former including a strong biotic component. We carried out DNA sequencing of the pellets in an attempt to establish presence of microorganisms (Acetic Acid Bacteria). None was found. Subsequently, and as a working hypothesis, we propose a series of (biotic/abiotic) reactions which were likely to have taken place in the liquid and vapour phases and on the metal surface. The hypothesis aims to demonstrate that CO2 would be microbially induced and would increase, as a function of time, resulting in cerussite forming over and above hydrocerussite/other Pb-rich phases. Psimythion has for long been valued as a white pigment. What has perhaps been not adequately appreciated is the depth of empirical understanding from the part of psimythion manufacturers of the reactions between abiotic and biotic components within ‘oxos’/pot, as key drivers of minerals synthesis. Ultimately, psimythion manufacture may rest in understanding the nature of ‘oxos’, antiquity’s relatively little researched strongest acid.

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SEM Backscattered-Electron Images of Paint Cross Sections as Information Source for the Presence of the Lead White Pigment and Lead-Related Degradation and Migration Phenomena in Oil Paintings

Microscopy and Microanalysis ◽

10.1017/s1431927610094444 ◽

2011 ◽

Vol 17 (5) ◽

pp. 696-701 ◽

Cited By ~ 33

Author(s):

Katrien Keune ◽

Annelies van Loon ◽

Jaap J. Boon

Keyword(s):

Cross Sections ◽

Layer Structure ◽

Information Source ◽

Particle Morphology ◽

Paint System ◽

Lead White ◽

White Pigment ◽

Oil Paintings ◽

Backscattered Electron ◽

And Migration

AbstractScanning electron microscopy backscattered-electron images of paint cross sections show the compositional contrast within the paint system. They not only give valuable information about the pigment composition and layer structure but also about the aging processes in the paint. This article focuses on the reading of backscatter images of lead white-containing samples from traditional oil paintings (17th–19th centuries). In contrast to modern lead white, traditional stack process lead white is characterized by a wide particle size distribution. Changes in particle morphology and distribution are indications of chemical/physical reactivity in the paint. Lead white can be affected by free fatty acids to form lead soaps. The dissolution of lead white can be recognized in the backscatter image by gray (less scattering) peripheries around particles and gray amorphous areas as opposed to the well-defined, highly scattering intact lead white particles. The small particles react away first, while the larger particles/lumps can still be visible. Formed lead soaps appear to migrate or diffuse through the semipermeable paint system. Lead-rich bands around particles, at layer interfaces and in the paint medium, are indications of transport. The presence of lead-containing crystals at the paint surface or inside aggregates furthermore point to the migration and mineralization of lead soaps.

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Investigation of proteinaceous paint layers, composed of egg yolk and lead white, exposed to fire-related effects

Scientific Reports ◽

10.1038/s41598-020-75876-y ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Lea Legan ◽

Klara Retko ◽

Kelly Peeters ◽

Friderik Knez ◽

Polonca Ropret

Keyword(s):

Amino Acids ◽

High Temperatures ◽

Negative Impact ◽

Test Chamber ◽

Aromatic Amino Acids ◽

Egg Yolk ◽

Lead White ◽

Lead Carbonate ◽

White Pigment ◽

Molecular Changes

Abstract Fires can have a negative impact on the environment, human health, property and ultimately also on various objects of cultural heritage (CH). This paper deals with an investigation into the degradation of selected proteinaceous paint layers that were exposed to fire-related effects (i.e., fire effluents and/or high temperatures) in a modified cone-calorimeter system. Paint layers of egg yolk adhesive (E) and lead white tempera (E + LW) were exposed to fire-related impacts on top of a CH stack and in a specially designed CH test chamber. On the CH stack, the proteinaceous paint layers were exposed to fire effluents and high temperatures, while in the CH test chamber, the samples were exposed mainly to fire effluents. The molecular changes to the exposed paint layers were analysed by invasive and non-invasive spectroscopic analyses (i.e., FTIR and Raman spectroscopy) and complimented with pyrolysis-GC–MS, while the colour changes were evaluated using colourimetry. It was concluded that the proteinaceous binder degrades into aromatic amino acids and/or fatty acids after exposure to the overall impacts of the fire. Aromatic amino acids were detected by means of the FTIR and py-GC–MS analyses. In the case of the lead white tempera exposure, partial dissociation of the lead white pigment was confirmed by the detection of alteration products, such as lead oxide and lead carbonate. Moreover, the investigation of the E + LW samples exposed for longer times revealed the presence of lead carboxylates. On the other hand, no significant molecular changes were observed with the CH samples exposed to fire effluents in the CH test chamber. The research offered us an insight into the fire-induced effects on selected paints for the first time.

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Thermal Decomposition of Lead White for Radiocarbon Dating of Paintings

Radiocarbon ◽

10.1017/rdc.2019.64 ◽

2019 ◽

Vol 61 (5) ◽

pp. 1345-1356 ◽

Cited By ~ 6

Author(s):

Lucile Beck ◽

Cyrielle Messager ◽

Stéphanie Coelho ◽

Ingrid Caffy ◽

Emmanuelle Delqué-Količ ◽

...

Keyword(s):

Thermal Decomposition ◽

Organic Matter ◽

Radiocarbon Dating ◽

Extraction Yield ◽

Lead White ◽

Synthetic Route ◽

White Pigment ◽

Metallic Lead ◽

Historical Samples

ABSTRACTLead carbonates were used as cosmetic and pigment since Antiquity. The pigment, known as lead white, was generally composed of cerussite and hydrocerussite. Unlike most ancient pigments, lead white was obtained by a synthetic route involving metallic lead, vinegar and organic matter. Fermentation of organic matter produces heat and CO2 emission, leading to the formation of carbonates. As lead white is formed by trapping CO2, radiocarbon (14C) dating can thus be considered. We have developed a protocol to prepare lead white. We selected modern pigments for the experiment implementation and ancient cosmetic and paintings for dating. After characterization of the samples by XRD, thermal decomposition of cerussite at various temperatures was explored in order to select the appropriate conditions for painting samples. CO2 extraction yield, SEM and XPS were used to characterize the process. Thermal decomposition at 400°C was successfully applied to mixtures of lead white with other paint components (oil as binder, calcite as filler/extender) and to historical samples. We obtained radiocarbon measurements in agreement with the expected dates, demonstrating that thermal decomposition at 400°C is efficient for a selective decomposition of lead white and that paintings can be directly 14C-dated by dating lead white pigment.

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Thermal analysis of carbonate pigments and linseed oil to optimize CO2 extraction for radiocarbon dating of lead white paintings

Microchemical Journal ◽

10.1016/j.microc.2020.104637 ◽

2020 ◽

Vol 154 ◽

pp. 104637

Author(s):

Cyrielle Messager ◽

Lucile Beck ◽

Laurence de Viguerie ◽

Maguy Jaber

Keyword(s):

Thermal Analysis ◽

Radiocarbon Dating ◽

Linseed Oil ◽

Lead White

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Pigment Degradation in Oil Paint Induced by Indoor Climate: Comparison of Visual and Computational Backscattered Electron Images

Microscopy and Microanalysis ◽

10.1017/s1431927616000076 ◽

2016 ◽

Vol 22 (2) ◽

pp. 448-457 ◽

Cited By ~ 13

Author(s):

Katrien Keune ◽

Rick P. Kramer ◽

Zara Huijbregts ◽

Henk L. Schellen ◽

Marc H.L. Stappers ◽

...

Keyword(s):

Image Analysis ◽

Chemical Degradation ◽

Lead White ◽

Indoor Climate ◽

Visual Interpretation ◽

White Pigment ◽

The North ◽

Backscattered Electron ◽

North Wall ◽

Computational Image Analysis

AbstractFor the first time the degradation of lead white pigment in mature oil paint has been used as an internal marker for the degree of saponification and hence chemical degradation of oil paint. Computational image analysis of the backscattered electron images quantified the degree of the intact lead white pigment versus the nonpigmented and lead-rich areas (degraded lead white) in the paint layers. This new methodology was applied to a series of paint samples taken from four painted wall hangings (dated 1778), which makes it possible to study the influence of indoor climate on chemical degradation of aged oil paintings. The visual interpretation and computational image analysis of the backscattered electron images revealed clear trends. The highest degree of lead white degradation in the room was found in samples from the north wall close to the windows, whereas degradation diminished further away from the window. Lead white from the south wall was less degraded, but showed a similar trend as in the paintings on the north wall. These results imply a strong relationship between chemical degradation of paint and location of the paint in the room.

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Microchemical analysis of Leonardo da Vinci’s lead white paints reveals knowledge and control over pigment scattering properties

Scientific Reports ◽

10.1038/s41598-020-78623-5 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Victor Gonzalez ◽

Selwin Hageraats ◽

Gilles Wallez ◽

Myriam Eveno ◽

Elisabeth Ravaud ◽

...

Keyword(s):

Da Vinci ◽

Leonardo Da Vinci ◽

Lead White ◽

X Ray Diffraction ◽

White Pigment ◽

X Ray ◽

Microchemical Analysis ◽

Precise Knowledge ◽

And Control

AbstractLeonardo da Vinci (1452–1519) is a key artistic and scientific figure of the Renaissance. He is renowned for his science of art, taking advantage of his acute observations of nature to achieve striking pictorial results. This study describes the analysis of an exceptional sample from one of Leonardo’s final masterpieces: The Virgin and Child with St. Anne (Musée du Louvre, Paris, France). The sample was analyzed at the microscale by synchrotron-based hyperspectral photoluminescence imaging and high-angular X-ray diffraction. The results demonstrate Leonardo’s use of two subtypes of lead white pigment, thus revealing how he must have possessed a precise knowledge of his materials; carefully selecting them according to the aesthetical results he aimed at achieving in each painting. This work provides insights on how Leonardo obtained these grades of pigment and proposes new clues regarding the optical and/or working properties he may have tried to achieve.

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