Cadmium Yellow Research Articles

An investigation into the synthesis of cadmium sulfide pigments for a better understanding of their reactivity in artworks

Cadmium yellows are a class of inorganic pigments introduced during the middle of the 19th c. and widely employed by modern painters. Recent research has reported the degradation of cadmium yellow paints in important artworks such as The Scream by Edward Munch, raising questions about its triggering factors. To address this issue, we investigated, for the first time, the historical production methods of Winsor & Newton, one of the leading suppliers of artists’ materials. Starting from in-depth documentary research of the Winsor & Newton 19th c. archive database, the foundation for an informed selection of historical preparation methods of these yellow pigments was provided. This allowed us to replicate 19th c. recipes, enabling us to understand better historical synthesis processes and their impact on the properties of cadmium yellow pigments. The pigments prepared, as well as reference pigments, were characterized through surface-sensitive methods in a multi-faceted analytical approach. The results show that pigments synthesized following historical indications present polytype crystal structure and crystal grains and aggregates much smaller than reference pigments. More interestingly, the detection of chlorine ions on particles surface (in the form of Cl bonded to a metal) was possible by X-ray Photoelectron Spectroscopy analysis, allowing its exclusion as an environmental contaminant. Finally, we have observed a strong sensitivity of the photoluminescence emission to pigment crystallite and grain size, an occurrence which may significantly impact on the photo-reactivity of the pigment in artworks.

The palette of Pio Collivadino (1869–1945) throughout his career

Abstract This article focuses on the analysis of the pigmentary palette of Pio Collivadino (1869–1945), an Argentinian artist of outstanding influence in the national art of the early twentieth century. By using Raman spectroscopy on micro-samples taken from a selected corpus of the Pio Collivadino Museum consisting of representative works of different moments of his production, we were able to unambiguously detect several pigments in the artist’s palette: lead white, vermillion, Prussian blue, chrome yellows and oranges, synthetic ultramarine, zinc white, cadmium yellows and oranges, cobalt violet, viridian, cerulean blue, cadmium red and earth pigments (raw sienna and burnt sienna). The identification of the pigments used by Collivadino enabled us to set up a dialogue between his palette and those of the contemporary European artistic movements his work relates to: the Macchiaioli, the Scapigliati, the Divisionists (Italian artistic vanguards) and the Impressionists. The presence of Prussian blue, cerulean blue, viridian not mixed with emerald green and earth pigments relates Collivadino’s choice of pigments to that of the contemporary Italian artistic vanguards, distancing his palette from that of the Impressionists. The palettes of European artists active during the nineteenth century and the first half of the twentieth century have been widely studied making it possible to date the incorporation of the new bright and colorful pigments that were synthesized during this period. Taking into account Collivadino’s privileged position in the Art academic field, his choice of art materials may have influenced many artists whose works make up the Argentine national heritage. Therefore, the characterization of Collivadino’s pigmentary palette carried out here is an important step to date the incorporation of these bright new pigments in the Argentinian artists’ palettes. Besides Collivadino's work importance by itself, and due to his position of privilege, his palette also provides information about the availability of art supplies in Argentina during this period.

A preliminary study of Liu Kang\u2019s palette and the discovery and interpretation of hidden paint layers

This paper presents an overview of the results from the ongoing study on the materials and painting technique of the pioneering Singapore artist—Liu Kang. The paintings Zuo La Lu and Nude, which represent two of Liu Kang’s early and distinct artistic phases—Paris and Shanghai—were investigated for the first time using a combination of non- and micro-invasive techniques. The aim of this study was to identify the main pigments used by the artist and to add to the existing research on the artist’s painting methods. The results show that the majority of pigments used in both paintings are similar and include Prussian blue, ultramarine, viridian, strontium yellow, chrome yellow, cadmium yellow, iron oxides, lead, zinc and barium whites, bone black and organic red. Particularly interesting is the predominance of lead white in Zuo La Lu and zinc white in Nude. A comparison of the ground layers also indicates the presence of a lead white admixture in Zuo La Lu while its absence in Nude may point to a characteristic difference between two artistic phases, possibly determined by the availability of materials. The imaging methods revealed hidden compositions: the view of a canal house behind Zuo La Lu, and a mystery outdoor view behind Nude. Although these investigative methods permitted some visualisation of the discarded compositions, it remains difficult to determine their details.

Photoluminescence imaging of modern paintings: there is plenty of information at the microsecond timescale

Luminescent emission from artworks is usually employed by conservators and restorers as a visual and quick method for assessing the presence of protective varnishes and restoration materials, as well to evaluate the painting conservation status. Besides these mere qualitative observations, the analysis of both spectral and temporal features of the optical emission from a painting can provide useful information about the pictorial materials employed by artists. In this work we propose Multi-spectral Time-gated Photoluminescence Imaging to differentiate between luminescent pigments, on the basis of their different emission spectra and lifetimes. We present the application of the approach on two modern paintings from Fondazione Maimeri Private Collection, on which we differently probe the fast-living emission from surface varnish and lake pigment and the long-living trap state emissions from different semiconductor pigments. With the aid of the time gated detection we record the trap state emission of semiconductor pigments, otherwise covered by the intense fluorescence of the organic compound. The method is complemented with Macro-XRF analysis, to confirm the nature of the identified inorganic pigments, as zinc white and cadmium yellow. The protocol represents a rapid, non-invasive and reliable way for assessing the identification of luminescent pigments and their spatial distribution.

Judith and Holofernes: Reconstructing the History of a Painting Attributed to Artemisia Gentileschi

Recently, a new painting attributed to Artemisia Gentileschi was found in Ferrara, representing Judith exposing the head of Holofernes. Some analyses have been required to verify the history of this canvas, because another known painting is very similar to this one with the exception of the heads of Judith and Holofernes. This last has been attributed to the father of Artemisia, Orazio Gentileschi. Many diagnostics were performed, starting from imaging techniques: from raking light, to UV fluorescence and X-ray radiography. All of them highlighted peculiarities concerning above all the head of the main female protagonist. The results suggest that the face of Judith was subjected to various reworks in the same artistic period because of the original materials still present. This is the reason for the peculiar fragility and, due to this, the restoration of the 20th Century focused on Judith’s face. However, in this contribution, we want to highlight the results obtained with XRF spot analysis. Indeed, the artistic palette and the restoration materials have been characterized. For example, reds are in cinnabar, while Judith’s lips have been restored with cadmium red. The more interesting results regard the use of umber earths. In the painting, this iron-based pigment, rich in manganese, was revealed several times, and the correlation between Fe and Mn was easily verified. More than one correlation has been found due to the use of this pigment to darken the hues.

Rational approach to synthesis low-cost BiVO4–ZnO complex inorganic pigment for energy efficient buildings

Bismuth vanadate (BiVO4) gathered great attraction as a yellow inorganic pigment which could replace the conventional chrome and cadmium yellow. However, its high cost over other yellow pigment restricted its usage. Therefore, there is a huge demand is existing to develop cost-effective BiVO4 inorganic pigment without compromising its optical properties. In this work, we demonstrate an effective strategy to develop low-cost BiVO4 complex pigments. Nano particles of BiVO4 decoration on white pigment are achieved by the citrate-gel method. An appreciable decrease in BiVO4 content (75%) has been observed. The reduction in the BiVO4 have shown a remarkable impact on the economic viability of the new complex pigment. The developed complex inorganic pigment exhibited excellent greenish-yellow colour (a* = −6.28, b* = 76.45), which is similar to pure BiVO4. An exceptional near infrared reflectance has been recorded, which is estimated as high as 90%. High reflective coatings of developed complex pigment displayed significant response for temperature shielding experiment, could achieve reduction of 8.4 °C in the interior temperature, compared to the commercially available yellow coating. Moreover, the present work demonstrates that developed complex pigment could be a potential replacement for BiVO4 yellow pigment.

Metropolitan Collections: Reaching Out to Regional Australia

Metropolitan Collections: Reaching Out to Regional Australia

Kandinsky\u2019s fragile art: a multidisciplinary investigation of four early reverse glass paintings (1911\u20131914) by Wassily Kandinsky

This work highlights the rediscovery of the technique of reverse glass painting by the artists of the “Blaue Reiter” collective in the early 20th-century and focusses particularly on the role of Wassily Kandinsky (1866–1944). Kandinsky created more than 70 reverse paintings on glass and showed several of them in exhibitions together with paintings on canvas and cardboard, implying a coequal importance of these techniques. Four of his early (1911–1914) reverse glass paintings (Auferstehung, Allerheiligen II, Rudern, Apokalyptischer Reiter II) were selected for investigation and their iconography, painting techniques and painting materials were examined. Two paintings were executed on so-called cathedral glass, revealing a “hammered surface”, whereas Kandinsky used a corrugated glass panel for Rudern. A multi-analytical, non-invasive approach [X-ray fluorescence (XRF), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), VIS spectroscopy (VIS), Raman spectroscopy] was taken to identify the pigments and classify the binding media. The results reveal a broad palette of materials. Several pigments like lead white, zinc white, strontium yellow, Prussian blue, viridian, cadmium yellow, ultramarine blue, cinnabar and carbon black were found in most of the four paintings. The use of the rare synthetic organic pigments PR60 and PB52 is discussed. In two works of art, cadmium carbonate is associated with cadmium yellow. The identification of aluminium foil along with tin foils in Rudern indicates an early use of this material for reverse glass paintings.

Laboratory multi-technique study of Spanish decorated leather from the 12th to 14th centuries.

This work comprises an exhaustive study of Spanish decorative leathers dating from the 12th to 14th centuries. These paintings are considered a key example of a crucible of artistic styles: Gothic, Islamic and Florentine Trecento. The goal of this work was to use the scientific information provided by a number of experimental techniques - namely EDX, micro-FTIR, micro-Raman and micro-XRD - to assess the dating of the wooden vault, leather preparation and filling fibres. Another goal was to assess the artistic technique based on the characterization of pigments and the differentiation between original materials and those added throughout its history. Gypsum was the original preparation layer extended over the leather. A new preparation stratum was added in further interventions with the artwork. The original pictorial materials and those used during refurbishments have been identified. Original pigments were: red lead, Mars red, red lake, cinnabar, lapis lazuli, red ochres, raw sienna, white lead and charcoal black. Gilding was also found. Pigments added during restoration were: barite, emerald green, rutile, anatase, Mars red, cadmium red, lithopone, cadmium yellow, charcoal black and orpiment.

Laser ablation inductively coupled plasma mass spectrometry appointed to subserve pigment identification

Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) was used apart from Scanning Electron Microscopy (SEM) equipped with Energy Dispersive Spectroscopy (EDS) and Raman spectroscopy (RS) to support identification of inorganic pigments from historic oil painting. Samples in form of tiny particles were collected from painting layer during conservation processes. Detection of lead white (2PbCO3·Pb(OH)2); Naples yellow (Pb2Sb2O7); lead‑tin‑antimony yellow (Pb2SnSbO6.5); ochre (Fe2O3); ultramarine (Na8–10Al6Si6O24S2–4); smalt (CoO·nSiO2); cadmium yellow (CdS); malachite (2CuCO3·Cu(OH)2); chrome yellow (PbCrO4); ceruleum (CoSnO3), chalk (CaCO3); Schweinfurt green, Cu(C2H3O2)2·3Cu(AsO2)2; vermilion (HgS) and carbon black (C) is documented in this work. The aim of this study was to estimate eventual benefits for using LA-ICP-MS to attain coherent elemental and molecular information of paint micro-samples for cross-checking the reliability of their chemical identification. The use of LA-ICP-MS was helpful to get detailed elemental data for some mixtures of pigments when only microscopic amount of material was available for examinations.

How do you say “Bocour” in French? The work of Carmen Herrera and acrylic paints in post-war Europe

The Cuban-American artist Carmen Herrera (born 1915) was the subject of a partial retrospective, titled Carmen Herrera: Lines of Sight, held at the Whitney Museum of American Art, New York, in the fall of 2016. On this occasion, it was noted that the artist had listed the binding media for all the paintings in the exhibit as acrylic even though the earliest works date from the late 1940s to early 1950s, when Herrera was in Paris and acrylics were not yet known to be commercially available in Europe. Questioned about the unexpected media assignments, Herrera recalled buying early acrylic paints in an art supply store near her studio in the French capital. Thus, for this study, a selection of five paintings by Carmen Herrera dated from 1948 to 1952, for which there was no sign or record of previous conservation treatments, were analyzed with a variety of non-invasive and micro-invasive instrumental techniques to characterize the painting materials in order to ascertain whether early experimental acrylic formulations might have been used. A preliminary investigation of the elemental composition of the paints entailed non-invasive analysis of the artworks with X-ray fluorescence spectroscopy. Twenty-one paint samples were then removed from selected areas for micro-invasive examination. Fourier-transform infrared spectroscopy and pyrolysis–gas chromatography/mass spectrometry with and without sample derivatization with tetramethyl ammonium hydroxide were employed to gather detailed information on the chemical composition of the binding media. In addition, complementary analyses by Raman spectroscopy and scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy were conducted to shed light on the pigments, colorants, and extenders present. Results revealed that the paints are composed of a range of both traditional and modern materials, including: calcite, gypsum, barite, and titanium white (in the form of rutile and anatase); cadmium yellows, oranges, and reds; Pigment Red 83 – the synthetic counterpart of natural dye alizarin (1,2-dihydroxyanthraquinone) – precipitated onto an aluminum-rich substrate; viridian and emerald green; cerulean blue, cobalt blue, as well as Prussian blue; iron-containing earths and umber-based pigments; as well as bone and/or ivory black. More remarkably, a complex progression of organic binders was uncovered: mixtures of modified oils, detected in paintings dated to 1948 and 1949, were gradually replaced or combined with other binding media, such as acrylics (mostly n-butyl methacrylate), polyvinyl acetate, and oil-based alkyds based on ortho-phthalic acid, in works painted during the following three years. Remarkably, the first occurrence of acrylic binders was observed in a painting dated to 1949, well before the date of introduction to the European market of the first acrylic-based paints by George Rowney & Sons in 1963. In addition to offering insight into Herrera's materials and techniques, this study represents a major advancement in the current scholarship regarding the availability and use of acrylic-based artists’ paints in Europe.

Frontispiece: Role of the Relative Humidity and the Cd/Zn Stoichiometry in the Photooxidation Process of Cadmium Yellows (CdS/Cd1−xZnxS) in Oil Paintings

Frontispiece: Role of the Relative Humidity and the Cd/Zn Stoichiometry in the Photooxidation Process of Cadmium Yellows (CdS/Cd_1−<i>x</i>Zn_<i>x</i>S) in Oil Paintings

Role of the Relative Humidity and the Cd/Zn Stoichiometry in the Photooxidation Process of Cadmium Yellows (CdS/Cd1-x Znx S) in Oil Paintings.

Cadmium yellows (CdYs) refer to a family of cadmium sulfide pigments, which have been widely used by artists since the late 19th century. Despite being considered stable, they are suffering from discoloration in iconic paintings, such as Joy of Life by Matisse, Flowers in a blue vase by Van Gogh, and The Scream by Munch, most likely due to the formation of CdSO4 ⋅n H2 O. The driving factors of the CdYs degradation and how these affect the overall process are still unknown. Here, we study a series of oil mock-up paints made of CdYs of different stoichiometry (CdS/Cd0.76 Zn0.24 S) and crystalline structure (hexagonal/cubic) before and after aging at variable relative humidity under exposure to light and in darkness. Synchrotron radiation-based X-ray methods combined with UV-Vis and FTIR spectroscopy show that: 1) Cd0.76 Zn0.24 S is more susceptible to photooxidation than CdS; both compounds can act as photocatalysts for the oil oxidation. 2) The photooxidation of CdS/Cd0.76 Zn0.24 S to CdSO4 ⋅n H2 O is triggered by moisture. 3) The nature of alteration products depends on the aging conditions and the Cd/Zn stoichiometry. Based on our findings, we propose a scheme for the mechanism of the photocorrosion process and the photocatalytic activity of CdY pigments in the oil binder. Overall, our results form a reliable basis for understanding the degradation of CdS-based paints in artworks and contribute towards developing better ways of preserving them for future generations.

First principles study of the optical emission of cadmium yellow: Role of cadmium vacancies

We study the role of structural defects in the CdS-based cadmium yellow paint to explain the origin of its deep trap states optical emission. To this end, we combine a first principles study of Cd- and S- vacancies in the wurtzite (101¯0) CdS surface with experimental photoluminescence spectroscopy of the commercial hexagonal CdS pigment. Computational results clearly state that the presence of cadmium vacancies in the pigment surface alters the electronic structure of cadmium sulfide by forming acceptor levels in the gap of the semiconductor. Such levels are consistent with the optical emission from trap state levels detected in the CdS pigment. This finding provides a first step towards the understanding of the photo-physical mechanisms behind the degradation of this modern pigment, widely used in impressionist and modernist paintings.

Time-Resolved Photoluminescence Microscopy for the Analysis of Semiconductor-Based Paint Layers.

In conservation, science semiconductors occur as the constituent matter of the so-called semiconductor pigments, produced following the Industrial Revolution and extensively used by modern painters. With recent research highlighting the occurrence of various degradation phenomena in semiconductor paints, it is clear that their detection by conventional optical fluorescence imaging and microscopy is limited by the complexity of historical painting materials. Here, we illustrate and prove the capabilities of time-resolved photoluminescence (TRPL) microscopy, equipped with both spectral and lifetime sensitivity at timescales ranging from nanoseconds to hundreds of microseconds, for the analysis of cross-sections of paint layers made of luminescent semiconductor pigments. The method is sensitive to heterogeneities within micro-samples and provides valuable information for the interpretation of the nature of the emissions in samples. A case study is presented on micro samples from a painting by Henri Matisse and serves to demonstrate how TRPL can be used to identify the semiconductor pigments zinc white and cadmium yellow, and to inform future investigations of the degradation of a cadmium yellow paint.

The artists\u2019 materials of P. S. Kr\xf8yer: An analytical study of the artist\u2019s paintings and tube colours by Raman, SEM\u2013EDS and HPLC

An analytical study of two paintings by P. S. Krøyer and the tube colours found in his painting cabinet has been carried out in order to investigate the artists’ materials used by Krøyer in the latter part of his oeuvre. The study has given a valuable knowledge about Krøyer’s choice of materials and their composition that may be helpful in e.g. preservation issues. The pigments and dyes were analysed by micro-Raman spectroscopy (MRS), scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM–EDS), and high-performance liquid chromatography with diode-array detection (HPLC–DAD). The technical analyses were supplemented with archival studies of Danish nineteenth century paint shops. The results show that Krøyer used commercially available artists’ materials typical for that period in time. Being a wealthy artist, he seems to have favoured expensive pigments such as cobalt blue, viridian and cadmium yellow. Based on the analyses, the main development in Krøyer’s palette is the substitution of lead white with zinc white that appears to have taken place after 1886. The results also show that the contents of the tube colours in some cases differ from what was expected based on the trade names. This is particularly observed for the tube colours named “Oxide rouge” of which only one contains the expected hematite pigment, while all the remaining contain cadmium sulfide and natural organic red lakes. A rare tube colour named “Laque verte clair” was characterised to be mixture of Prussian blue and synthetic Indian yellow. The study therefore also illustrates that it was not always obvious to the artists what they bought from their colour merchant. It hence relates to existing international studies of nineteen century artists’ materials, which highlight the complexity of tube colours from this particular period in time.Graphical abstractP. S. Krøyer’s portrait of Holger Drachmann and some of the tube colours used by Krøyer.

A multi-analytical study of the Belarusian icon “Virgin Eleusa” (XVII cent.)

Abstract Here the results are reported on the multi-analytical study of the Belarusian icon “Virgin Eleusa” (XVII cent.). The X-ray and luminescence studies revealed some interventions performed in different time periods. The materials of original painting as well as the materials of interventions were successfully characterized by spectroscopic techniques. Layer-by-layer Laser induced breakdown spectroscopy (LIBS) was used for elemental composition study of art materials. Fourier-transform infrared microspectroscopy (micro-FTIR) was used to indicate the types of binding media in the grounds and paint layers as well as to identify the art pigments. A low concentration of cerulean and cadmium yellow in the upper paint layers (interventions) were identified by Surface enhanced Raman scattering (SERS). Since cerulean and cadmium yellow are known to come into use in XIX cent., the SERS results played the crucial role for dating of some intervention.

Discovery of a woman portrait behind La Violoniste by Kees van Dongen through hyperspectral imaging

Despite the fact that Kees van Dongen was one of the most famous painters of the twentieth century, only little information about his palette and his technique is available. To contribute to the characterization of van Dongen’s painting materials, La Violoniste, painted by the artist around 1922, has been analyzed by using three complementary techniques: macro X-ray fluorescence (MA-XRF), Raman spectroscopy and hyperspectral imaging. The elemental repartition given by MA-XRF and the results obtained thanks to Raman spectroscopy help us to complete the identification of pigments contained in La Violoniste (lead white, iron oxides, cadmium yellow, vermilion, Prussian blue, titanium white, ultramarine, a red lake, a chromium pigment and carbon black) while the results obtained via hyperspectral imaging reveal a hidden woman portrait. Besides the fact that Kees van Dongen was particularly renowned for his female portraits, this hidden composition presents stylistic similarities with the well-known portraits produced by the artist from around 1920, when he was a famous worldly portraitist. Thanks to Raman spectroscopy, visual examination and MA-XRF, we show that the original background contains ultramarine, the hidden portrait’s clothes are maybe made of the same colour as the present violinist’s dress and her face contains zinc, contrary to the violinist’s flesh which is mainly made of lead white.

Micro‐Raman spectroscopy and complementary techniques (hXRF, VP‐SEM‐EDS, μ‐FTIR and Py‐GC/MS) applied to the study of beads from the Kongo Kingdom (Democratic Republic of the Congo)

In the framework of the inter‐disciplinary KongoKing project, a set of beads from archaeological excavations in the Democratic Republic of the Congo was analysed by means of a minimally invasive, multi‐analytical approach based on micro‐Raman spectroscopy. The full characterization of the materials, including glassy network, opacifiers and colorizers, was achieved thanks to the combination of data from handheld X‐ray fluorescence, variable pressure scanning electron microscopy coupled with energy‐dispersive X‐ray spectrometry, micro‐Fourier transform infrared spectroscopy and pyrolysis coupled to gas chromatography and mass spectrometry. The obtained chemical information was used to fill the existing gap in the chemical study of beads from Western Central Africa. The cobalt‐rich blue beads were found to be of Central European origin, while the copper‐rich turquoise beads were manufactured using distinct copper sources. Cadmium yellow and cadmium red are the colourants responsible for the bright colours of bead types 10 and 12, respectively. The type 12 beads were found to be composed of glass covered with a waxy layer tentatively identified as Japan wax. Prosser‐moulded bead type 9 was coloured by means of a chrome–tin pigment, while a combination of Mn and Fe is responsible for the black colour of the type 47 beads. Cuprite is most likely responsible for the red hue of glass layers from type 14. The dark palm green exterior of the type 17 bead was produced by using a combination of Cu and Fe compounds; iron was the only chromophore detected in the Indian red decoration. Copyright © 2017 John Wiley &amp; Sons, Ltd.

Electrochemical characterization of biodeterioration of paint films containing cadmium yellow pigment

The voltammetry of microparticles (VMP) methodology was used to characterize the biological attack of different bacteria and fungi to reconstructed egg tempera and egg–linseed oil emulsion paint films containing cadmium yellow (CdS), which mimic historical painting techniques. When these paint films are in contact with aqueous acetate buffer, different cathodic signals are observed. As a result of the crossing of VMP data with attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), scanning electrochemical microscopy (SECM), field emission scanning electron microscopy (FESEM), and atomic force microscopy (AFM), these voltammetric signals can be associated with the reduction of CdS and different complexes associated to the proteinaceous and fatty acid fractions of the binders. After biological attack with different fungi (Acremonium chrysogenum, Aspergillus niger, Mucor rouxii, Penicillium chrysogenum, and Trichoderma pseudokoningii) and bacteria (Arthrobacter oxydans, Bacillus amyloliquefaciens, and Streptomyces cellulofans), the observed electrochemical signals experience specific modifications depending on the binder and the biological agent, allowing for an electrochemical monitoring of biological attack.