A pioneer of acrylic painting: new insights into Carmen Herrera’s studio practice

Carmen Herrera, born on May 30th, 1915, is a Cuban American abstract minimalist artist, whose first solo show was held at the Whitney Museum of American Art, New York, in 2016–2017. On this occasion, a scientific study of five paintings from the artist’s time in Paris (1948–1953) revealed her pioneering use of solvent-based acrylic paints in post-war Europe. This article presents a second phase of research into Herrera’s work aiming to shed light on her studio practice and ascertain the possible presence of other early acrylic paints in her pre-1963 artistic production. A selection of four paintings, namely Iberia #25 (1948), Iberic (1949), Flights of Colors #16 (1949), and Early Dynasty (1953), was subjected to an analytical campaign that relied on both non-invasive and micro-invasive techniques. Results confirmed the use of both oil and solvent-based acrylic paints, supporting our primary research and uncovering the first-known occurrence of acrylic binders in Herrera’s Iberia #25. In all cases, the ground layer consists of a mixture of titanium white in its tetragonal form of rutile, anhydrite, and talc, while the color palette was found to be based on both traditional and modern pigments. In most areas, several paint layers appeared to be overlaid on top of one another, revealing a creative process that developed through subsequent compositions. Remnants of earlier paint layers, which appeared to have been scraped off before new ones were applied, were observed directly above the ground in some of the samples examined. In addition, Iberia #25 and Iberic, with analogous geometric and chromatic schemes, underwent technical imaging, which exposed pencil lines and notes underneath the paint layers likely indicative of the intended design and polychromy. Besides corroborating a major alteration in the current scholarship on the availability and use of acrylic-based artists’ paints in post-war Europe, this research provides new insights into Herrera’s materials, techniques, and studio practice. In addition, the results of this scientific study assisted the development of a suitable treatment plan for Iberic in preparation for its display in The Metropolitan Museum of Art’s galleries as part of the museum’s 150th anniversary exhibition Making The Met, 1870–2020.

Analyses and findings of unusual substitute materials in a raincoat from WWII

Due to the coating materials used, historic raincoats are vulnerable to degradation and rarely survive long periods of time. The investigated raincoat dating from 1943 is no exception—the coating is unusually stiff and flaking off in areas around folds and cracks. Study into its material composition can contribute to important knowledge of the availability of materials for waterproof clothing during the time of the German occupation of Denmark (1940–1945) when the usual materials for raincoats, cotton fabric and rubber, were in short supply. Optical microscopy and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) identified the fabric to consist of rayon staple fibres and paper yarn, and the coating to be based on cellulose nitrate (CN) lacquer and an unknown plasticiser. Though the results are atypical for a raincoat, they are in good accordance with the raw materials available in Denmark in 1943. Analysis by matrix-assisted laser desorption-ionisation mass spectrometry (MALDI-MS), and 1H and 13C nuclear magnetic resonance spectroscopy (NMR), identified the plasticiser as poly(1,3-butylene) adipate. Powder X-ray diffraction (PXRD) moreover identified the pigment as titanium white of the anatase form. By historical discussion, this study argues that IG Farben is the likely producer of poly(1,3-butylene) adipate, even though the first known marketing of the plasticiser is from 1986 where the Swiss firm Ciba-Geigy introduced poly(1,3-butylene) adipate as a plasticiser for PVC cling films under the tradename Reoplex® 346. The results give an interesting insight into the use of substitution products during WWII and provide new information on polymer science of the time.

A Basic Research for Preservation of Works Exhibited in the Outdoor Sculpture Park - A Scientific Analys is of Painted Work ‘Conversion’ Exhibited in the Cheonmasan Sculpture Park -

Outdoor sculptures of modern art works are being damaged and deteriorated as they are exposed to the outdoor environment due to the nature of exhibition in the outdoor environment, but secure of basic data through the measures for conservation and advanced researches still remain in the early stage. The surface of “Conversion” which is exhibited in the Busan Cheonmasan Sculpture Park has been exfoliated and deteriorated due to outdoor exhibition for a long time, so systematic conservation and management of works are considered necessary. Prior to the conservation and management, this study conducted observation of cross section, analysis of inorganic components, FT-IR, Raman and Py-GC/Mass analysis to examine the nature and type of paints used for the work through a scientific analysis. As a result of analysis, paints used for the “Conversion” include paint mixed with silvery aluminium powder and white pigment, reddish paint mixed with toluidine red, bluish paint that mixed prussian blue and titanium white and mixture of phthalocyanine blue and titanium white. The result is expected to be used as basic data for selecting materials necessary for conservative treatment of and establishing a plan for conservative treatment of the “Conversion”.

Towards building a Cathodoluminescence (CL) database for pigments: characterization of white pigments

Paintings and painted surfaces are considered to be extremely complex due to their multitude of materials and thus form the basis for particularly intricate Cultural Heritage studies. The combination of Scanning Electron Microscopy (SEM) with Cathodoluminescence (CL) can serve as a powerful tool for the identification of individual pigments. SEM/CL has the potential of identifying both organic and inorganic pigments and can focus on a micrometer or even nanometer scale. The combination with Energy Dispersive Spectrometry (EDS) allows for robust, cross-checked, elemental and mineralogical characterization of pigments. In order to apply SEM/CL in a routine-based way for the identification of pigments, it is necessary to have a robust, open-access database of characteristic CL spectra of pigments. A large project has been undertaken to create such a database, focusing primarily at the pigments, both organic and inorganic, which were most commonly used from antiquity until today. In the present paper, the CL characterization of common white pigments is presented. White pigments were selected, due to their significance and frequency of use, since they were also present on the ground layers or mixed with other pigments in most of the painting layers. More specifically, the CL spectra of samples in pure form of calcite, kaolinite, lead white, zinc oxide, barium sulfate, lithopone and titanium white are presented. In all cases, the CL spectra present characteristic bands, which allow for a secure identification of the pigments. In order to facilitate comparison with other databases, EDS and RAMAN spectra are also presented. Additionally, the effect of weathering on the CL spectra was evaluated, by comparison to naturally and artificially aged samples and to pigments identified on areas of two paintings, of the 19th and 20th c., respectively. Finally, the effect of binding media was also studied, using combination of pigments with four common media: egg yolk, linseed, walnut and poppy oil. Overall, both weathering and binding media appear to cause minor differences in the occurring spectra, without preventing the identification of pigments.

Reviving Alexander Calder’s Man-Eater with Pennants: A Technical Examination of the Original Paint Palette

Mat-Eater with Pennants, a rarely exhibited sculpture in Alexander Calder’s oeuvre, was commissioned by The Museum of Modern Art (MoMA) and installed in 1945. To exhibit the large standing mobile in Alexander Calder: Modern from the Start (2021), the derelict sculpture had to be remediated; this initiated a collaborative investigation with conservation scientists, conservators, curators, and the Calder Foundation into the original paint colors hidden beneath layers of repaint. XRF analysis was carried out to elucidate the paints’ composition, followed by sampling for analysis to assess the paint stratigraphy and binders. Scrapings were analyzed by µ-FTIR and Raman spectroscopies; cross sections were examined with optical microscopy and analyzed with SEM-EDS. Analysis differentiated between the original paints, which contain Prussian blue, parachlor red, chrome yellow, and the many layers of overpaint, which contain titanium white, molybdate orange, a variety of β-Naphthol reds, red lead, and ultramarine. A model for Man-Eater, Mobile with 14 Flags, is also part of the museum’s collection, and was first considered as a point of reference for the original colors. Similar analysis, however, indicates that the maquette was painted after the Man-Eater was first installed, therefore is not representative of the original colors. In addition to investigating an early primary palette for Calder’s outdoor sculptures, this study helped develop the plan for the restoration of the original color scheme of Man-Eater.

Formation of Metal Soaps In Oil Paintings Under Variable Environmental Conditions

Formation of metal soaps in model paintings under cyclic temperature and relative humidity conditions has been studied by ATR-FTIR and compared with the standard controlled conditions generally maintained in many museums and storerooms. Three different white pigments (lead, zinc and titanium white) and two types of linseed oils (cold-pressed and alkali-refined) have been tested. The behaviour in short times (up to 6 weeks) depends on the pigment and environmental conditions. The relative humidity conditions have been shown to influence the metal soap formation in more degree than the temperature. Ageing under low cyclic relative humidity (30-50%) promotes metal soap formation in both lead and zinc white pigments, compared to high relative humidity (50-90%) conditions. Besides, the formation of zinc soaps continues for 6 weeks when low cyclic relative humidity is used, but it stops after 3 weeks under the other ageing conditions studied.

Analyses and Findings of Unusual Substitute Materials in a Raincoat From WWII

Due to the coating materials used, historic raincoats are vulnerable to degradation and rarely survive long periods of time. The investigated raincoat dating from 1943 is no exception – the coating is unusually stiff and flaking off in areas around folds and cracks. Study into its material composition can contribute to important knowledge of the availability of materials for waterproof clothing during the time of the German occupation of Denmark (1940-1945) when the usual materials for raincoats, cotton fabric and rubber, were in short supply. Optical microscopy and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) identified the fabric to consist of rayon stable fibers and paper yarn, and the coating to be based on cellulose nitrate (CN) lacquer, an unknown plasticizer and titanium white (TiO2). Though the results are atypical for a raincoat, they are in good accordance with the raw materials available in Denmark in 1943. Analysis by matrix-assisted laser desorption-ionization mass spectrometry (MALDI-MS), and 1H and 13C nuclear magnetic resonance spectroscopy (NMR), identified the plasticiser as poly(1,3-butylene) adipate. Powder X-ray diffraction (PXRD) moreover identified the titanium white pigment as the anatase form. By historical discussion this study argues that IG Farben AG is the likely producer of poly(1,3-butylene) adipate, even though the first known marketing of the plastiticiser is from 1986 where the Swiss firm Ciba-Geigy introduced poly(1,3-butylene) adipate as a plasticiser for PVC cling films under the tradename Reoplex® 346. The finding is an extraordinary example on how advanced the chemical industry was in the early 1940’s when it came to polymer science.