Papers by Gregory D Smith
Heritage, Feb 27, 2024
This article is an open access article distributed under the terms and conditions of the Creative... more This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY
Applied Sciences
Cleaning painted surfaces of their grime, aged varnishes, and discolored overpaint is one of the ... more Cleaning painted surfaces of their grime, aged varnishes, and discolored overpaint is one of the most common interventive treatments for art conservators. Carefully concocted solvent mixtures navigate the solubility differences between the material removed and the original paint underneath. However, these solutions may be altered by differential evaporation rates of the component solvents (zeotropic behavior), potentially leading to ineffectively weak cleaning or conversely overly strong residual liquid capable of damaging the underlying paint. Azeotropic solvent blends, which maintain a constant composition during evaporation, offer a promising solution. These blends consist of two or more solvents combined at precise concentrations to function as a single solvent. Additionally, pressure-maximum azeotropes feature higher vapor pressure compared to other mixtures, further minimizing contact time and sorption of the solvents into artworks. This study examines azeotropes of isopropano...
Journal of The American Institute for Conservation, Jul 27, 2019
In the mid-1980s, Stephen Sprouse designed a leather motorcycle jacket, the back of which was sub... more In the mid-1980s, Stephen Sprouse designed a leather motorcycle jacket, the back of which was subsequently painted by muralist Stefano Castronovo. The silver jacket depicts the unmistakable albeit fluorescent greenface of the Mona Lisa. Designed as club-wear, the garment's full visual effect is only achieved under black lights. Exhibiting the jacket under ultraviolet radiation with its concomitant degradation concerns presented an ethical conundrum: exhibited this way, the jacket demonstrates to museum visitors the effect desired by Castronovo, but the lifetime of the fluorescent colors would be further shortened. Castronovo's striking painting already suffered from delamination and cracking due to the flexible leather garment. Inpainting these losses was complicated by the jacket's potential short-term display in both the visible and ultraviolet spectrum. Scientific analysis was conducted at the Indianapolis Museum of Art at Newfields on the original fluorescent paints and potential conservation materials to investigate solutions for display and documentation under both lighting conditions. This paper explores how the potential display of a leather jacket painted with daylight fluorescent pigments under visible and/or ultraviolet radiation impacted the treatment, interpretation, and exhibition. The jacket was stabilized, inpainted, and subsequently featured in an exhibition, taking into account the abovementioned research. RÉSUMÉ Dans les années 1980s, Stephen Sprouse conçut un blouson de motocyclette en cuir, le dos duquel fut par la suite peint par le muraliste Stefano Castronovo. Le blouson argenté démontre indéniablementbien que vert fluorescentle visage de la Mona Lisa. Conçu pour être porté dans les discothèques, l'effet visuel complet du blouson n'est accompli que sous les lumières noires retrouvées dans les boîtes de nuit. Permettre l'exposition du blouson sous rayons ultraviolets, étant donné les effets de dégradation connexes à ceux-ci, présente une énigme déontologique : exposé ainsi, le blouson révèlerait au public l'effet voulu par Castronovo, cependant la durée de vie des couleurs fluorescentes serait raccourcie davantage. L'image saisissante créée par Castronovo souffrait de délamination et d'écaillement de la couche picturale causé par la nature flexible du vêtement en cuir. La retouche de ces pertes fut compliquée par l'exposition potentielle du blouson, à court terme, aux spectres visibles et ultraviolets. Une analyse scientifique fut entreprise à l'Indianapolis Museum of Art à Newfields, sur la peinture fluorescente d'origine ainsi que sur les matériaux de restauration potentiels, avec pour but d'étudier les solutions menant à l'exposition et la documentation du blouson sous ces deux conditions d'éclairage. Cet article explore l'effet qu'aurait l'exposition aux rayons visibles et/ ou ultraviolets d'un blouson de cuir peint à l'aide de pigments fluorescents à la lumière du jour, sur le traitement, l'interprétation, et l'exposition de l'oeuvre. Le blouson fut stabilisé et un protocole de retouche fut développé. Le blouson fut par la suite mis en valeur dans une exposition, en tenant compte de la recherche entreprise sur les pigments fluorescents. Traduit par Anne-Marie Guérin. RESUMO Em meados da década de 1980, Stephen Sprouse projetou uma jaqueta de couro para motociclista, cuja parte posterior foi pintada pelo muralista Stefano Castronovo. A jaqueta prateada retrata a inconfundível-embora verde fluorescente-face da Mona Lisa. Concebida para uso em clubes, o efeito visual completo da peça só é alcançado sob as luzes negras, como as encontradas em boates. Permitir que a jaqueta seja exibida sob radiação ultravioleta, com todas as preocupações inerentes de degradação, apresentou uma questão ética: exibida desta forma, a jaqueta monstra ARTICLE HISTORY
Solvent mixtures are often fine-tuned by art conservators for the difficult tasks of safely remov... more Solvent mixtures are often fine-tuned by art conservators for the difficult tasks of safely removing yellowed varnishes and obfuscating dirt from oil paintings. These two goals are often loosely termed " picture cleaning. " Concern has been raised over the impact of differential evaporation rates for solvents in the cleaning mixture. Differential evaporation can lead to changes in the mixture's potency over time and potentially lead to solvent mixtures on the surface of the artwork having solubility characteristics deleterious to artists' oil paints. Azeotropic mixtures of solvents have been proposed as an alternative for maintaining consistent solvent composition. Azeotropes are specific mixtures of two or more solvents that behave as a single solvent and maintain a constant composition at their boiling point. The azeotropes that have appeared in the art conservation literature are taken from tables of azeotropic compositions in the CRC Handbook given at their boi...
Forensic Science International: Synergy, 2021
The handling of cultural heritage objects has become a highly debated topic in the last decade. T... more The handling of cultural heritage objects has become a highly debated topic in the last decade. The work and outcomes described in this paper are aimed to provide objective data to assist in making appropriate decisions as to whether or not wearing gloves is appropriate in a given situation. The forensic fingermark development techniques of 1,2-indandione and single metal deposition II were used to investigate the efficacy of handwashing and glove use to improve the information available when deciding whether to use gloves when handling paper objects. It was found that fingermarks did not permeate through polymer glove types but could through cotton gloves. It was also shown that the amounts of observable fingermark residues were greater 5 min after handwashing than if handwashing had not occurred, undermining previous arguments for not wearing gloves if hands could be washed before object handling.
Forensic Chemistry, 2019
A simple technique is described to create nanoscale near-infrared luminescent Egyptian Blue pigme... more A simple technique is described to create nanoscale near-infrared luminescent Egyptian Blue pigment particles with lipophilic surfaces for latent fingermark detection. An exfoliated Egyptian blue powder coated with cetrimonium bromide was prepared using a simple, one-pot process. Particle size and surface coatings were characterized using scanning electron and atomic force microscopies, dynamic light scattering, and infrared and luminescence spectroscopies. This new fingermark dusting powder presented more contrast compared to uncoated Egyptian blue of comparable particle size as well as commercial visible light fluorescent (Blitz Red) and near infrared luminescent (fpNatural1) powders in the detection of aged fingermarks on model surfaces. The coated Egyptian blue pigment presents a cost-effective fingermark dusting powder that reveals high contrast latent fingermarks with simple, inexpensive photography equipment.
Proceedings of the National Academy of Sciences, 2019
Significance Can radiocarbon ( 14 C) dating uncover modern forgeries? Radiocarbon dating has the ... more Significance Can radiocarbon ( 14 C) dating uncover modern forgeries? Radiocarbon dating has the potential to answer the question of when an artwork was created, by providing a time frame of the material used. In this study we show that with two microsamples (<500 μg), from both the canvas and the paint layer itself, a modern forgery could be identified. The canvas dating is consistent with the purported attribution to the 19th century; however, the 14 C age gained on the paint contradicts this as it offers clear evidence for a post-1950 creation. Thus the additional dating of the paint reveals the forger’s scheme where the repainting of an appropriately aged canvas was used to convey the illusion of authenticity.
ACS Symposium Series, 2012
We have recently demonstrated that exfoliated Egyptian blue powder coated with cetrimonium bromid... more We have recently demonstrated that exfoliated Egyptian blue powder coated with cetrimonium bromide is effective for detecting latent fingermarks on a range of highly-patterned non-porous surfaces (see reference). In this extension of that work, we here present our preliminary studies into alternative approaches to preparing exfoliated Egyptian blue with a variety of different coatings. The various powders were then applied to the detection of latent fingermarks on non-porous surfaces. This proof of concept study demonstrated that there is potential improvement in performance compared to our previous work, however more comprehensive studies are required to compare the quality of the fingermarks developed with these powders against particles exfoliated in water.
De Gruyter eBooks, Feb 24, 2020
Forensic Science International: Synergy, 2021
The use of forensic dye analysis in the field of cultural heritage is introduced, and a case stud... more The use of forensic dye analysis in the field of cultural heritage is introduced, and a case study is presented determining the dating of a potentially important textile fragment from the Cleveland Museum of Art. The fragment, attributed on stylistic grounds to the 15th century, is purportedly the oldest surviving example of a Persian knotted-pile silk carpet. Raman spectroscopy combined with liquid chromatography e mass spectrometry determined the dyes used in the fragment include Metanil yellow, Congo red, and indigo, possibly in its synthetic form. Based on the dates of introduction for these dyes (1879, 1884, and 1897, respectively) and the first appearance of the textile fragment in 1928, the object is shown to be almost certainly a late 19th or early 20th century creation. Furthermore, impurities found in the red dye are suggested as potential markers of a pre-1970s synthetic route for manufacturing Congo red or possibly degraded Congo red due to environmental pollutants.
Journal of Archaeological Science, Oct 1, 2004
... of the brown-black painted surfaces of sherds C (analysed earlier by FTIR microscopy) and L .... more ... of the brown-black painted surfaces of sherds C (analysed earlier by FTIR microscopy) and L ... Its presence was revealed here because the analysis could be focused selectively through a ... nature of the iron-containing material could be specified because Raman spectroscopy is a ...
Heritage Science, Nov 2, 2022
The accessioning of ancient textiles into museum collections often requires objective information... more The accessioning of ancient textiles into museum collections often requires objective information regarding the object's appropriateness and authenticity before purchase or gift acceptance. In the case of colored fabrics, the identification of dyestuffs consistent with the attributed time period and culture builds confidence and reduces the chances of the object being a simple forgery or fake produced using modern materials. Moreover, this information adds to the technical, cultural, and conservation knowledge regarding the object. Increasingly, chronometric age estimates in the form of radiocarbon dating are also needed to establish the object's age or to further prove the materials match the purported date range of the textile. Each of these analyses consumes a small sample of the object, and typically they are conducted separately by different laboratories on individual sample yarns. This report demonstrates for the first time the sequential, combined analysis of dyes by liquid chromatography-diode array detection-mass spectrometry and radiocarbon dating of the same residual dye-extracted sample. The chemicals and solvents used in various dye extraction protocols are shown not to contaminate the extracted yarns for radiocarbon dating purposes. The approach was used in the authentication study of an ancient Nazca tunic made from natural fibers (wool) and dyes (indigoids, anthraquinones, and flavonoids) shown to have most likely been produced between 595 and 665 CE.
Heritage Science, Aug 16, 2019
The exploitation of natural sources and later synthetic molecules to generate blue to purple colo... more The exploitation of natural sources and later synthetic molecules to generate blue to purple coloration in textiles has a long history in the dyer's craft. Natural indigoids such as indigo, woad, and Tyrian or shellfish purple served this purpose for millennia, but in the late 1800s synthetic analogs, in particular indigotin, quickly replaced natural sources. Halogenated versions of the dye were also created, and some like 5,5′-dibromoindigo were brought to market. Interestingly, these have not been significantly discussed in the literature, nor have they been found in forensic or technical art history investigations of textiles until now. This paper reports the first identification in a museum context of this unusual synthetic brominated analog of indigo, discovered on three twentieth century Japanese yukata. Analytical data collected on reference materials using liquid chromatography-mass spectrometry, UV-visible spectroscopy, Raman microspectroscopy, Fourier transform infrared spectroscopy, and X-ray fluorescence spectroscopy are provided to assist with future identifications of this relatively unknown colorant. Density functional theory applied to 5,5′-dibromoindigo was used to confirm the experimental Raman spectrum.
Acs Symposium Series, Sep 3, 2021
Studies in Conservation, Dec 1, 2002
ABSTRACT
Dyes and Pigments, Aug 1, 2016
Chemical analysis of dyes on an Uzbek ceremonial coat: Objective evidence for artifact dating and... more Chemical analysis of dyes on an Uzbek ceremonial coat: Objective evidence for artifact dating and the chemistry of early synthetic dyes, Dyes and Pigments (2016),
Journal of Chemical Education, Dec 1, 2009
Figure 1. The Kinamax WCM-6LNV night-vision webcam and modified lens cap with 87C visible light b... more Figure 1. The Kinamax WCM-6LNV night-vision webcam and modified lens cap with 87C visible light blocking filter.
Journal of paper conservation, Jul 3, 2022
Heritage
Museum professionals must ensure that protective enclosures for artworks do not in fact cause dam... more Museum professionals must ensure that protective enclosures for artworks do not in fact cause damage to the objects within due to pollution off-gassing from the container’s components. Ideally, all materials used in proximity to artworks should be assessed for their potential to emit harmful volatiles. The standard approach used in the museum field, known as the Oddy test, requires significant effort and time and can produce unreliable results if not conducted by a trained staff member, all of which reduce the likelihood that proper vetting will be rigorously employed. This paper reports a methodology utilizing a microfurnace pyrolyzer coupled to a gas chromatograph with a mass spectrometer to optimize these assessments and produce actionable results with minimal time and expense. Simple confirmatory chemical tests augment the direct thermal desorption (DTD) experiment, and as a last resort, time-consuming accelerated aging tests are utilized if deemed necessary to eliminate or deci...
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Papers by Gregory D Smith
A translated and updated version of the paper in Greek presented at the Annual Meeting of Panhellenic Association of Conservators of Antiquities, 03-12-2016, Athens.
Translation: Kassiani Kagouridi, Editing: Victor J. Chen and Gregory D. Smith, Proofreading: Chryssa Panagiotopoulou.