Ancient Polychromy Research Articles

Analytical methodological adaptations for sampling ancient pigments in provenance research

Mineral pigment provenance is a promising direction in cultural heritage particularly in ancient polychromy research. The analysis of trace elements and Pb-isotopes can provide clues about the origin of pigment raw materials. While previous investigations already showed great potential for provenancing archeological-historical mineral pigments, sampling methods and reference data collections need to be developed further to evaluate the potential and limitations of this type of research. This work tests a new sampling method for pigment provenance research that collects sample material with easily available (suffused) cotton swabs for analysis by mass spectrometry. Three artifacts decorated with Egyptian blue and red pigments were selected for comparing sampling with cotton swabs to sampling with a scalpel. All three artifacts date to the 1st century BCE: The first is a colossal marble head from Lazio, Italy, which probably belonged to a seated cult statue of Zeus, and with extensive remains of ancient red paint. The two artifacts (a slag and a fragment of a terracotta vessel) were recovered during Petrie's excavations of an Egyptian blue production facility in Memphis, Egypt. The new results are consistent with previous studies, which provides the necessary quality control for the cotton swab sampling method. This work contributes to improving sampling methods for pigment provenance analysis as well as to a better understanding of past pigment production and trade networks.

Facing death: a multidisciplinary analysis of a Romano-Egyptian mummy mask at the Ny Carlsberg Glyptotek, Copenhagen

Funerary masks played a crucial role in ancient Egyptian burial practices, as part of the rituals to ensure a successful afterlife. This study presents the first comprehensive analysis of a gilded mummy mask from the Roman period in Egypt from the collections of The Ny Carlsberg Glyptotek in Copenhagen. Portraying a young female, the mask belongs to a distinctive group of mummy masks, whose origins can be identified to be coming from the Dakhlah and Kharga oases. The construction of the mask (plaster, textiles) and the constituents of its polychromy (pigments, binding media) was analysed using various non- and micro-destructive methods: imaging, cross-section analysis, optical microscopy, Fourier transform infrared spectroscopy and scanning electron microscopy coupled to energy-dispersive X-ray spectroscopy. Additionally, samples were taken for palaeoproteomic analysis with liquid chromatography–tandem mass spectrometry. A wide range of pigments such as yellow and red ochre, carbon-based black, and Egyptian blue were identified, reflecting common materials in polychromy in Egypt during the Roman period. Notably, indigo was detected, suggesting its usage in mixtures to render purple hues. Analysis of adhesives and media identified plant gum and collagen-based animal glue. Proteomic analysis identified Equus asinus (donkey) as the predominant protein source for the collagen-based glue. The results shed light on the materials and techniques employed in ancient polychromy in Egypt in the Roman period, further enriching our understanding of artistic practices at the time.

Investigating Organic Colorants Across Time: Interdisciplinary Insights into the use of Madder, Indigo/Woad, and Weld in Historical Written Sources, Archaeological Textiles, and Ancient Polychromy

Organic dyes have been used from the earliest times to provide color primarily to textiles, but also as a colorant in painting. Such organic dyes could create a wealth of colors, depending on the availability and know-how of resources. These dyes are usually organic in nature, and primarily obtained from different plant sources. Unfortunately, the characterization of natural organic colorants in textiles and artworks is still a challenge. The difficulty of analyzing these materials is sometimes allied to the frequent impossibility of micro-sampling, and the frailty of the objects. Many techniques, such as HPLC (High-Performance Liquid Chromatography) and SERS (Surface-Enhanced Raman Spectroscopy), require the use of a micro-sample, which cannot be recovered after analysis. Moreover, the portable technique Fibre Optic Reflectance Spectroscopy (FORS) can present some challenges in distinguishing between different dye sources belonging to the same molecular family, such as anthraquinone reds. Although no one technique alone can unravel the world of natural dyes, a multi-analytical approach has proven to be far more effective for their identification and characterization. In the present article, we intend to share insights into three different perspectives and types of source material for the study of the use of organic colorants in ancient and historical times: The first case study presents an 18th-century historical recipe for dyeing textiles, the second case study presents a study of preserved archaeological textiles from Nubia, while the third case study presents the use of organic colorants for the polychromy of ancient Greco-Roman iconography.

What were the colors of the Parthenon? Investigation of the entablature's cornice blocks

The present study is focused on the investigation of the remaining ancient paint layers of the Parthenon's west cornice blocks. Most ornamental features that referred in the 19th century literature as the cornice blocks' decoration, still survive on the Parthenon. Τhe paint layers were studied by using imaging techniques (Visible induced luminescence and portable digital microscope) in situ along with various techniques in lab (Stereomicroscope, μ-Raman spectroscopy, ATR-FITR spectroscopy and SEM/EDX).The obtained results revealed that the taenia, which is placed at the bottom of the cornices’ facade, was depicted with the mineral conichalcite, providing a vivid green color. Red ochre and egyptian blue were used for the viae and the mutules depiction. The bottom side of the guttae, was also painted with red ochre. Regarding the taenia, placed at the base of the cornice blocks, two blue pigments, azurite and Egyptian blue were used for the meander and chess pattern depiction, respectively. The pattern of meander/chess pattern was placed on a red background (red ochre). Red lead was used for the depiction of the brown-red line borders in the corner ceiling of the NW cornice block and most probably for the depiction of the corner ceiling's background. In microsamples deriving from well preserved areas, beeswax was identified mixed with pigments, serving as the binder of the paint layers (encaustic technique). It is the first time that the presence of beeswax is proven in paint layers of an ancient monument, exposed in an open-air environment. The presence of beeswax is in line with ancient inscriptions, which referred to the encaustic technique for the decoration of ancient monuments.This is the first systematic investigation of the Parthenon’s ancient polychromy and the obtained data are compared with the 19th century sources’ information. The scientific investigation not only confirms or invalidates these data, but also presents new findings.

Wax finishing in Roman polychrome statuary: Ganosis on the colossal head from Dougga (Tunisia)

• Ancient sources describe the recipes and cultural values of the wax finish of the statues, known as ganosis. • Recipes are described by Pliny and Vitruvius, but never archeologically attested. • Time-of-Flight Secondary Ion Mass Spectrometry analyses are performed on one Roman statue from Dougga. • The use of wax finish, following the ancient recipes, and the potential of the TOF-SIMS are demonstrated for the first time in the study of ancient polychromy of statues. The material evidence for the wax finish on ancient marble statues, known as ganosis, is scarce and controversial, although Greek and Latin sources describe the recipes and cultural value of this treatment. The surface treatment of a colossal Roman head from the Roman theatre of Dougga (Tunisia), dated to the end of the second century CE, is studied by a multi-analytical protocol (video-microscope, cross section, and time-of-flight secondary ion mass spectrometry of one sample). The results of this physico-chemical analysis and the comparison with ancient recipes, prove the use of ganosis on a Roman statue and explore, for the first time, the application of the recipes described in ancient sources. This result shows the potential of the Time-of-Flight Secondary Ion Mass Spectrometry analysis, detecting at the same time organic and inorganic materials and their stratigraphy, to study the ancient recipes.

Impure stone and the threat to decency: marble tints and veins

According to the classical tradition, marble sculptures were to be made of ‘pure’ white material. This remained an aesthetic ideal even after archaeological findings had revealed evidence of ancient polychromy. This article argues that tinting as well as natural staining on marble figures in the late eighteenth and nineteenth centuries were not only aesthetically but also morally reprehensible, because they violated the ideal of homo clausus. This term, coined by the sociologist Norbert Elias, conceptualizes a subject that imposes ‘self-restraint’ to control its physical body and its emotions. Perfect control was seen embodied in the ancient images of the gods, which were assumed to have been made of immaculate white marble. Any colouring, whether of natural origin or deliberately produced, seemed to contaminate this concept. My investigation is focused on the historical justifications for John Gibson’s scandalous Tinted Venus, and figures of veined marble rejected in France on similar grounds in the late eighteenth century, such as Christoph-Gabriel Allegrain’s Venus and Jean-Antoine Houdon’s Frileuse. I examine how the coloured veins and tints of the stone gained semantic qualities in female figures, where a blush or a vein seemed to reveal emotions and desires and thus infringe the ideal.

Olympian Jupiter. Winckelmann and Quatremère de Quincy on Ancient Polychromy

A number of Western museums may boast of their important collections of Classical Greek and Roman art. Marble statues of deities or heroes from Classical Antiquity, and important works in painting and architecture from different historical epochs, have traditionally made up the canon of Western art. In recent years, critics have claimed that this tradition represents an idealisation of the white, Caucasian body type which excludes other races from the concept of beauty. Although we today know that ancient statues in marble were often painted in vivid colours, they say that art theorists have either been ignorant of, or glossed over, this fact. While the German art historian Johann Joachim Winckelmann has often been regarded as a proponent of our Western predilection for whiteness, the French archaeologist Antoine Chrysostome Quatremère de Quincy is by many celebrated as the first to realise the extent and importance of ancient polychromy. In this paper, I will try to show that this is a distorted view, especially where Winckelmann’s theories are concerned. Far from being ignorant about ancient polychromy, Winckelmann was an important source for Quatremère de Quincy. In addition, Winckelmann’s appreciation of the white marble surface was not the result of racial prejudice, but the expression of an aesthetic opinion that he shared with Quatremère de Quincy.

Colour Experiments. The Harpy Monument: a Section of the West Side

Reconstructions of ancient polychromy on statuary are often the result of meticulous scientific research: pigments and barely visible remnants of decoration are identified. A pigment, however, does not provide evidence of the character of the paint layer, i.e. whether it was opaque or translucent, matte or glossy. As no intact, original paint layers remain, there are many uncertainties regarding paints and painting techniques. What can be seen on marble are faint traces of paint. In the present paper I will draw on my study of the so-called Harpy monument: the questions posed, the methods applied, the series of tests that were conducted and my suggestion of a possible polychromy. My starting point was the idea that monuments send messages to the viewer: the size of the object and the materials with which it was made indicate the commissioner’s social and economic status. Figures and myths illustrate the cultural context, and they reflect values cherished by the commissioner. Colours and shades also transmit messages. The reconstructive part of the project was limited to one of the west side segments, a relief showing a woman enthroned, but in order to understand the monument as a whole its four sides were considered more broadly, taking into account its Anatolian context.

The rarest blue: An exceptional find of lapis lazuli in the polychromy of a funerary portrait from ancient Palmyra

The current interdisciplinary study of a funerary portrait has provided the first identification of a blue pigment on Palmyrene sculpture. The exceptional attestation of lapis lazuli on the examined portrait confirms the use of this highly valuable semiprecious stone in ancient polychromy, which was previously thought to be a later addition to the painter's palette. Considering that the archaeological record contains numerous minor objects carved from lapis lazuli, there are astonishingly few known instances of its use as a pigment. This Palmyrene discovery is only the third known example from Antiquity.

Macroscopic XRF imaging in unravelling polychromy on Mycenaean wall-paintings from the Palace of Nestor at Pylos

The wall painting fragments from the Mycenaean “Palace of Nestor” at Pylos, are characterized by their high artistic quality, their unusual iconographic variety and the use of tempera and secco painting techniques. Systematic in-situ XRF analyses combined with the results of other portable and laboratory analytical techniques have already revealed a rich gamut of inorganic pigments with respect to the common Aegean “palette”, including different white and black pigments, iron based ochres ranging from dark brown to orange and pinkish hues, manganese based umbers, natural copper based greens, goethite, Egyptian blue and organic purple dyes. Macroscopic X-ray Fluorescence (MA-XRF) imaging, although well-established for non-invasive analysis of historical or contemporary painted artworks has hitherto been applied in a few cases only regarding the study of ancient polychromy. The purpose of applying in-situ MA-XRF imaging on selected wall painting fragments from the Palace of Pylos was to evaluate the capabilities of this technique in identifying the composition of pigments and their spatial distribution within heavily deteriorated pictorial layers, and in revealing iconographic information invisible to the naked eye. The results of MA-XRF imaging allowed us to critically re-consider previous artistic reconstructions, providing significant evidence on the painting techniques and materials used by Late Bronze Age painters.

Multispectral Photogrammetry

The Ny Carlsberg Glyptotek and Rigsters 3D are exploring the potential of merging photogrammetry and multispectral imaging (MSI). MSI is a widely employed photographic method of analysis in studies of ancient polychromy. The collaboration has resulted in the first 3D model including visible-induced infrared luminescence (VIL) imaging, illustrating the distribution of the ancient synthetic pigment Egyptian blue. The collaboration illustrates how the combination of methods developed in the fields of humanities, natural sciences, and digital industries can contribute to knowledge exchange as well as the development of new ways of disseminating scholarly research in museum exhibitions as well as online and for teaching purposes.

The 8th round table on ancient polychromy (Paris, 2016)

On 15-16 November 2016, in front of a large audience, the Centre de Recherche et de Restauration des Musees de France (C2RMF) hosted the eighth international round table on ancient polychromy, organized with the support of the Universite Paris I-Pantheon Sorbonne and the Ecole francaise, Athens. After Copenhagen, London, Frankfurt, Athens and Florence, Paris seemed the natural choice for a venue conducive to discussion, given France’s active contribution to this field of research and the C2RM...

The identification of lac as a pigment in ancient Greek polychromy - The case of a Hellenistic oinochoe from Canosa di Puglia

An important example of a mixture of red colourants from plant and insect sources has been found during a recent investigation of a purple pigment on a 3rd century BC oinochoe from Canosa di Puglia present in the British Museum collection. Further investigation was carried out to elucidate both the nature of this pigment and its possible method of manufacture. In a practice typical of the period, Egyptian blue and a pink lake were found to be physically mixed to produce the purple pigment observed on the object. High pressure liquid chromatography coupled with mass spectrometry (HPLC-MS) revealed that the main colourant of the pink lake was derived from madder (Rubia spp.). However, the samples investigated also contained markers for insect-derived colourants from cochineal (Porphyrophora spp., in partial agreement with recent archaeological findings from Thessaloniki) and lac (Kerria Lacca Kerr). Despite allusions to its existence in ancient sources, evidence for the use of lac dye as a colourant (in a lake pigment) from Antiquity has never previously been found. In addition, markers indicative of tannins were also found in the mixture. This was interpreted as an indication of the reuse of a colourant that has been extracted from previously dyed textiles. Although common practice in the manufacture of red lakes from the 14th to 17th centuries, this may be the first evidence for this method to produce lake pigments found on an object from Antiquity.In addition to confirming the power of HPLC-MS in terms of the sensitivity and specificity of information, that in many cases allows species differentiation, these discoveries raise many questions, not least of which is the real extent of use of insect-derived colourants, as part of the polychrome palette of these votive objects and ancient polychromy in general. The implications of this use in the wider context of pigment manufacture in Antiquity, particularly in terms of the trade in raw materials, must also be considered.

A technical step forward in the integration of visible-induced luminescence imaging methods for the study of ancient polychromy

Photo-induced luminescence imaging techniques, such as UV-induced visible luminescence (UVL) and the more recently developed technique of visible-induced infrared luminescence (VIL), have been invaluable for the study of ancient polychromy, allowing the detection and mapping of luminescent materials, such as varnishes, consolidants, organic binders, and crucially, traces of pigments, organic and inorganic, that are often not visible to the naked eye. In the context of works from the Hellenistic period onwards, the detection of two pigments, Egyptian blue and rose madder lake, has been particularly pivotal in advancing the field. Current conventional methodologies for the digital mapping of these two luminescent pigments rely on the separate application of two techniques (VIL and UVL), each requiring a different illumination source and acquisition set-up. In this study, a novel approach is proposed, combining the use of visible-induced infrared luminescence and visible-induced visible luminescence to locate these two pigments. As the source of illumination in both cases is the same system of LEDs, the set-up has the advantage of requiring only minor filter changes between luminescence modes. The increased portability and safety compared to the use of methodologies that employ UV radiation represent notable advantages of this integrated system. The interchangeability between highly selective excitation sources, also significantly simplifies the experimental set-up and the need to adjust the object or equipment between acquisitions, ensuring better reproducibility of the data acquired and facilitating any post-processing procedures. This results in a user-friendly methodology for both experts and non-specialists alike. Three Hellenistic period terracottas; two from Canosa di Puglia, Italy (270–200 BC) and one from Myrina, Turkey (c. 100 BC), all characterised by large well-preserved areas of decoration in Egyptian blue and red lake, were studied in order to trial the approach. Comparisons were made with the more standard techniques of VIL and UVL, and it was shown that the combined method proposed efficiently detects and maps both of these pigments with analogous results to those obtained by more established methodologies. The observations made from the multispectral images acquired were verified by analysis of small samples of the pigments, using FTIR and Raman spectroscopy and HPLC-DAD analysis.

Armenian cochineal (Porphyrophora hamelii) and purpurin‐rich madder in ancient polychromy

Samples removed from funeral figurines, dated the third to the second century BC (Hellenistic period) and found in Macedonia, Greece, are investigated using high‐performance liquid chromatography. Two results are reported that provide new insights into ancient polychromy. Firstly, high‐performance liquid chromatography results, in combination with historical information, indicate that insect species of cochineal, most probably Porphyrophora hamelii Brandt, was used in Hellenistic objects. Secondly, madder detected in the archaeological samples contains high amounts of purpurin (alizarin is either not detected or detected in trace). This relative composition, which is recorded using the hydrochloric acid method for dyestuff extraction, is consistent with that prepared from wild madder (Rubia peregrina L.), which is a common plant in the Mediterranean region.

Ancient Polychromy

Digital reconstruction of ancient polychromy is a relatively recent phenomenon in the history of archaeological and architectural heritage documentation. It has emerged as a result of new interest in the experimental archaeology and the technological development of computer graphic tools. Therefore, this article presents a project aimed at the scientific reconstruction of the original polychromy and the realistic rendering of an ancient sarcophagus, obtained with the use of some open source tools. In particular, starting from the accurate study of a polychrome Roman sarcophagus (National Roman Museum in Rome, inv. no. 125891), we show how the MeshLab tool was used to support the polychrome reconstruction stage and how Blender (or, rather, a combination of MeshLab and Blender) was used to achieve a more sophisticated visual presentation of the current and reconstruction ancient colour. A central role has been given to the rendering of different and overlapped layers of paint.

A multidisciplinary approach for the study and the virtual reconstruction of the ancient polychromy of Roman sarcophagi

Abstract In this paper, we report a multidisciplinary approach for the analytic study and the reconstruction of the ancient colour used for Roman sarcophagi. For this purpose, we adopted the three-dimensional (3D) digital technology and found it to be a valuable tool for the identification, documentation and reconstruction of the ancient colour. This technology proved to be an excellent link between archaeological knowledge and scientific analyses. Therefore, 3D digital technologies would effectively facilitate the exchange of information and collaboration between experts in various disciplines. This is extremely important in order to obtain demonstrable results in a new area of study, such as polychrome Roman sarcophagi (and the ancient polychromy and gilding on the marble). In this study, the digital 3D model of Ulpia Domnina's sarcophagus (National Roman Museum in Rome, inv. no. 125891) has been used to identify both the pigments and the techniques of application used, and to explore the potential of emerging technologies in the reconstruction and visualization of the ancient colour.

Introduction. Étudier et conserver la polychromie antique. Vidéo-microscopie et archéologie de la surface

On expose ici la conception d’un volume consacré au devenir matériel de la sculpture dans l’Antiquité, particulièrement aux soins (thérapéia) portés à entretenir l’éclat de la surface des effigies en Grèce ancienne. L’article rappelle l’apport des études en vidéo-microscopie dans une démarche d’archéologie historique de la couleur qui a permis de mettre en évidence des remaniements de surface antiques.

DIGITAL MAPING OF EGYPTIAN BLUE : CONSERVATION IMPLICATIONS

Egyptian blue was extensively used throughout the areas surrounding the Mediterranean from early dynastic Egypt until after the Roman Empire ended. A new, easily applied, technique to detect and map this pigment has been developed that takes advantage of its very strong photo-induced infrared luminescence. Using this method, single particles of pigment can be detected, even when concealed by layers of discoloured organic binding media, varnishes or inorganic patinas. A survey of sculptures, friezes, mosaics and wall paintings from the ancient cultures of the Mediterranean and the Middle East has revealed expected and unexpected occurrences of Egyptian blue and rediscovered lost decorative patterns. This technique not only offers information on the manufacture, decoration and condition of the object, but also provides an opportunity to map the use of Egyptian blue both geographically and temporally. These new perspectives on ancient polychromy can help to inform future preservation strategies and conservation treatments that take this new information into account.