Barbara Berrie

National Gallery of Art, Washington · Scientific Research

Considers the effect of fading yellow pigments on the appearance and reception (contemporary and current) of paintings by the eighteenth century French artist J.-B. Greuze

Leonardo's notes on painting materials and techniques are used to review results of technical analysis with a fresh eye. Analytical methods used include air-path XRF, infrared reflectography, optical microcopy and scanning electron microscopy of a paint cross section. Brief comparison to published work on other of Leonardo's female portraits are pr...

Formation and aggregation of metal carboxylates (metal soaps) can degrade the appearance and integrity of oil paints, challenging efforts to conserve painted works of art. Endeavors to understand the root cause of metal soap formation have been hampered by the limited spatial resolution of Fourier transform infrared microscopy (μ-FTIR). We overcome...

Materials in the paint layers of an early sixteenth-century painted and glazed terracotta sculpture by Giovanni della Robbia, Pietà were identified. The presence of the rare lead chloride salts, cotunnite (PbCl2) and challacolloite (KPb2Cl5), were confirmed using Raman spectroscopy and electron back scatter diffraction. Well-formed habit of large c...

Zinc oxide (ZnO) is a II-VI semiconductor that has been used for the last 150 years as an artists’ pigment under the name of zinc white. Oil paints containing zinc white are known to be prone to the formation of zinc carboxylates which can cause protrusions and mechanical failure. In this paper, it is demonstrated how a multispectral synchrotron-ba...

Oil paints comprise pigments, drying oils and additives that together confer desirable properties, but can react to form metal carboxylates (soaps) that may damage artworks over time. To obtain information on soap formation and aggregation, we introduce a new tapping‐mode measurement paradigm for the photothermal induced resonance (PTIR) technique...

Oil paints comprise pigments, drying oils and additives that together confer desirable properties, but can react to form metal carboxylates (soaps) that may damage artworks over time. To obtain information on soap formation and aggregation, we introduce a new tapping‐mode measurement paradigm for the photothermal induced resonance (PTIR) technique...

This paper describes a photoluminescence imaging approach coupled to a synchrotron source (SR-PL imaging) that provides a new, powerful way to probe the processes involved in metal soap formation in paint films, processes that play an important role in the deterioration of paint films in traditional and modern oil paintings.

New macroscale Imaging Spectroscopy (Reflectance and XRF) results on the Feast of the Gods

Cyclododecane (CDD) has been used for several years as a temporary consolidant for organic and inorganic materials of interest in cultural heritage. In this work, a comparative study has been conducted with CDD and three other sublimable compounds – menthol, camphene, and cyclododecanone – as protectants of water-sensitive paint during the desalina...

Microspectroscopic Investigation of Metal Soaps in Oil Paintings--a Case Study on late 19th Century Cobalt Green ((CoxZn1-xO) Paint - Volume 24 Supplement - Xiao Ma, Selwin Hageraats, Victoria Beltran, Mathieu Thoury, Matthieu Refregiers, Katrien Keune, Barbara H. Berrie

A comparison of the efficacy of aqueous PVAc/OH gels and swab cleaning on brass coupons and acrylic paint-outs.

We present a comparative study to determine whether residues remained on papers treated using the rigid polysaccharide gels of agarose and gellan gum and the viscous dispersion of methylcellulose. Experiments were carried out using fluorescein-tagged gels that allow greater sensitivity to the presence of residues than visual inspection alone. Using...

We have developed soft, peelable organogels from 40% hydrolyzed poly(vinyl acetate) (40PVAc) and benzene-1,4-diboronic acid (BDBA). The organic liquids gelated include dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, 2-ethoxyethanol, and methanol. The rheology of these soft materials can be tuned by altering the concentration of the polymer...

Background Color change in artworks has been commented on for centuries. Fading of watercolor pigments is a notable alteration. Pigments based on carminic acid are among those particularly prone to color loss, but the mechanism and factors are not well understood. Results We painted out three pigments prepared from the aqueous extract of carminic...

Single-sided NMR and gas chromatography were used in tandem to investigate the physical and chemical differences between traditional linseed oil paint and water-mixable oil paint. Water-mixable oil paints contain an emulsifier that confers water miscibility, but it may also affect the curing process and the intermolecular network formed in a cured...

To investigate soap formation in drying oils in historic paints, the reaction between metal acetates (K⁺, Zn²⁺, Pb²⁺) and ethyl linoleate (EL) was studied using optical microscopy, X-ray powder diffraction, and electron microscopy. Pb(II) and Zn(II) react rapidly with EL to form highly structured, spherulitic, luminescent crystallites that aggregat...

We report the influence of adding five short-chain glycol ethers (SCGEs) on the structure, stability, and viscoelastic properties of aqueous dispersions of partially hydrolyzed poly(vinyl acetate) and borax. The properties of these gel-like materials have been investigated as a function of the structure of the added SCGE both below and above the cr...

The important trecento Florentine artist Giotto (c. 1266-1337) is renowned for his naturalistic and realistic works in tempera and fresco. His innovative paintng style involved painting expressive, emotive faces and use of pictorial devices for depicting space. This report focuses on the analysis of the materials and methods used in a panel in the...

In the sixteenth century, the Erzgebirge mountains were mined for mineral ores of cobalt and antimony that were used to make the blue pigment smalt, a potash glass, and yellow pigments based on lead-antimony oxides, respectively. By the beginning of the seventeenth century, these pigments had found a permanent place on the easel painter’s palette,...

Viscoelastic, gel-like, polymeric dispersions (HVPDs) can be prepared by crosslinking poly-ols with borax or boric acid in water under alkaline conditions. Rheologically similar HVPDs have been prepared in organic liquids containing no water or hydroxylic groups through crosslinking partially or fully hydrolysed poly(vinyl acetate)s with trimethyl...

Deep ultraviolet (DUV) photoluminescence (PL) microimaging is an emerging approach to characterise materials from historical artefacts. Here we further assess the potentials of the method to access a deeper understanding of multi-layered varnishes coating wooden violins and lutes. Cross-section micro samples from important 16th- to 18th-century ins...

The use of microspectrophotometry to characterize cochineal in dyed wool is described. The effect of mordants and adjuvants on the absorbance and emission spectra was measured. Chromium, copper, and iron mordants and bases cause a red shift in absorbance spectra while tin and aluminum mordants and acids cause a blue shift. Cochineal mordanted with...

August 2014, pp 2014-2015 Copyright © Microscopy Society of America 2014 Published online: 27 August 2014

Heralded among America's master watercolorists, Winslow Homer (1836–1910) explored a wide range of themes, styles and techniques in the approximately 685 watercolors he painted from 1873–1905. This chapter discusses 59 watercolors from the collections of The Art Institute of Chicago and the National Gallery of Art, Washington DC, which encompass Ho...

A versatile gel-like system for the treatment of art has been prepared from partially hydrolyzed poly(vinyl acetate), borax, and large fractions of ethanol, isopropyl alcohol, n-propyl alcohol, and acetone. Variables such as the concentrations of the two gelating components, the degree of hydrolysis and molecular weight of the polymer, and the type...

In order to fully characterize the zinc white artists' pigment (ZnO), much used since the mid-nineteenth century, three samples collected in the early 20(th) century were studied using a combination of synchrotron and macroscopic photoluminescence spectroscopy and imaging. An improved microscope setup based on synchrotron microspectroscopy and micr...

Giorgio Vasari (1511-1574), architect, painter, and connoiseur, assembled a remarkable collection of drawings, referred to as the Libro de' Disegni. A rare and important example is in the collections of the National Gallery of Art, Washington, DC. It is a large, double-sided, richly embellished sheet with drawn frames for nine drawings attributed t...

Following a brief overview of the history of analysis of artists' pigments, I discuss the illustrative example of lead-tin yellow. Recent advances in our knowledge of artists' use of red lakes, glassy pigments, and metallic pigments in works of cultural heritage, particularly European paintings, as determined from chemical analyses are described.

UV-visible luminescence techniques are fre-quently used for the study of cultural heritage materials, despite their limitations for identification and discrimination in the case of complex heterogeneous materials. In contrast to tabletop setups, two methods based on the vacuum ultraviolet (VUV)-UV-visible emission generated at a bending magnet of a...

Pigment identification and technical analysis of works of art provide the historian and conservator with information that allows a new view of an object. The methods the analyst chooses depends on the nature of the sample and the materials and method expected for the age of the object being examined. Several analytical methods are used frequently i...

The works of art and artifacts that constitute our cultural heritage are subject to deterioration, both from internal and from external factors. Surfaces that interact with the environment are the most prone to aging and decay; accordingly, soiling is a prime factor in the degradation of surfaces and the attendant disfigurement of a piece. Coatings...

As Leona notes in a recent issue of PNAS (1), art and objects of cultural heritage hold information about the technology, trade, and aesthetics of a people. This knowledge can be accessed through chemical and material analysis combined with an understanding of the history of technology, science, and art. The information learned is of great value, e...

"Artist's Pigments...", volumes 1-4, offers comprehensive and authoritative (though somewhat dated) information on the pigments listed below. Future work entails updating and revising the chapters over the next few years. Volumes 1-3 can be downloaded at: https://www.nga.gov/global-site-search-page.html?searchterm=%22artists%27+pigments%22 Graphi...

Proposes that the links between Islamic and Venetian painting may lie in materials and techniques, and in the appearance and color of the paints used, rather than in the style and taste of the painters. Concludes that the transformations in Venetian painting from the last quarter of the 15th c. are due to the growing cosmopolitan attitude of its ci...

Discusses the technical aspects of color used in 16th-c. Venetian paintings. Touches on the adoption of oil as a medium, glazing techniques, the use of pigments intended for artists working in other media, and the role of the vendecolori or color sellers in painting developments. References: BHA,; 16 18066 (2006)

Science and connoisseurship come together in the examination and conservation of fine art. Chemical and physical analysis methods are used to examine art objects for a variety of purposes including the establishment of authenticity, schloarly investigation of the works, and evaluation of their state of preservation. Methods for analyzing the works...

In the light of new documentary information regarding the range of materials available to sixteenth century artists, cross sections from paintings were re-examined using scanning electron microscopy - energy dispersive spectrometry. Among a variety of new materials, colored glassy pigments were found including diverse yellow glassy particles, speci...

Connoisseurs and conservators of Japanese woodblock prints are familiar with the dark, sulfide-induced discoloration of white and red leads that is seen in prints of all periods. This is considered to be patina and is protected from conservation treatment. A group of prints dating from 1773 to 1912 reveal that two visually distinct types of discolo...

Since the important rediscovery by Jacobi in 1941 of the use of lead-tin yellow as a traditional artists' pigment, and the identification by Kühn of two distinct modifications of this material, elemental analysis and crystallographic determinations using X-ray diffraction (XRD), have been applied routinely to opaque yellow pigments from old master...

A short history of the pigment Prussian blue, including its discovery and preparation, how to identify it, it chemical properties, and how it was used in artworks.

The imprimatura in two paintings by Dosso Dossi (Ferrarese, ca. 1490-1542) were examined using scanning electron microscopy coupled with energy dispersive x-ray spectrometry. An assemblage of mineral species was found and identified, among them pyrite, dolomite, micaceous minerals, gypsum, and quartz. A high proportion of lead white was also found....

A mid fourteenth-century Spanish ciborium began to show signs of corrosion while on display in a closed case. The ciborium is made of gilded copper and champlevé enamel. The corrosion was found to be associated with a certain color of enamel. The enamel in the portions that evidence corrosion is itself much deteriorated. Though now a dull green-blu...

A mid fourteenth-century Spanish ciborium began to show signs of corrosion while on display in a closed case. The ciborium is made of gilded copper and champleve enamel. The corrosion was found to be associated with a certain color of enamel. The enamel in the portions that evidence corrosion is itself much deteriorated. Though now a dull green-blu...

Die Geschwindigkeitskonstunten für die Reaktion der Enol- und Keto-Form von ZA-Pentandion sind angegeben.

The rate constants for the reaction of enol and keto forms of pentane-2,4-dione with Ti³⁺ (at 25°C in 1 M LiCl) are 2.4 × 10³ M⁻¹ s⁻¹ and 0.7 M⁻¹ s⁻¹, respectively. (3-Formylpentane-2,4-dionato)bis(pentane-2,4-dionato)ruthenium(III) oxidizes Ti(III) in a reaction that involves two relaxations with rate constants kf′ ≅ k[Ti(III)]h[H⁺]⁻¹ + k′ and ks′...

Ru2(OAc)4+ is reduced by Ti(III) (at 25°C, in 1 M LiCF3SO3-HCF3SO3) by a two-term rate law, indicating that both Ti3+ and TiOH2+ are effective reductants for this oxidant. Rate constants are 2.3 × 102 and 3.4 × 103 M-1 s-1, respectively. Tris(pentane-2,4-dionato)ruthenium(III) is reduced by Ti(III), in 1 M LiCl-HCl at 25°C, by the same general rate...

The rate constant (25 °C;1 M-LiCl) for electron transfer through the bridging ligand in the kinetic intermediate bis (pentane-2,4-dionato)ruthenium (III)-µ-(3-formylpentane-2,4-dionato)titanium (III)(OH)2+ is 21 s–1.

Two main factors which govern rates of Ti(III) redox reactions which follow the inner-sphere mechanism are rates of substitution on Ti(III) and the extent of cross-bridge electronic interaction within the binuclear intermediate. Cross-bridge electronic interaction is more effective in Ru(III)-Ti(III) reactions than in Co(III)-Ti(III) reactions. Rat...