Egyptian Blue

Maya Blue is a colour that is more than a pigment; it had roles in status, ritual and performance, being daubed onto pots and people before sacrifice. Here researchers use experimental and historical evidence to discover how it was made, including direct scientific analysis of Maya Blue on a pot thrown into the sacred well at Chichén Itzá. The results indicate that the formation of the color was actually part of the ritual.

The archaeometric examination of Derveni’s Grave I began in 1995. The tomb was discovered at the site of Derveni in Thessaloniki, during the excavation of the access - dromos to the Macedonian tomb III. The burial monument dates back to the early 3rd century B.C. The rich painting decoration of the tomb is of great interest.There are four zones in the painting decoration: in the lower part there is an imitation of ortho-
marble, whereas the next part is decorated with a yellow ochre paint, followed by a decorative zone, which is a crowned by a doric molding. The main decorative theme comprise of garlands of flowers, which are intermittently interrupted. The most interesting part is the upper zone, where a blue background is present, showing objects which are related to the grooming and the costumes of the buried woman. Herein the previously collected results are revisited and moreover, for the first time, new results related to the decorative features of the tomb are presented. Initially the following techniques were used: polarizing microscopy, optical emission spectroscopy (OEA) and X-ray diffractometry (XRD). In the second step of the study, the following methods were employed: Scanning Electron Microscopy (SEM) in conjunction with Energy Dispersive Spectroscopy (EDS), Χ-Ray Fluorescence (XRF) and FTIR spectroscopy. The distinctive architecture of the tomb is associated
with the two different architectural bases of frescoes. The stone of the masonry is calcareous sandstone with its main components: quartz, feldspars and calcite. In the upper zone, the masonry is covered by lime
mortars, coarse grains and fine grains. In the lower zone on the clay basis, the mortar with a high content of lime and clayish material is first applied, followed by the fine-grained lime mortar.The lime-clayish mortar with the coarse-grained aggregates of the lower zone was produced by adding quartz sand and clay materials to the lime, in a possible
ratio of 2:1:1.5.The lime mortar with the coarse-grained aggregates
of the upper zone was produced by adding quartz sand and crushed marble to the lime, in a ratio of lime: aggregates (inert) 1:2. In contrast to the internal coarse-grained mortars, the supernatant fine mortars of both zones are of the same nature, namely lime, but with different qualitative
and quantitative compositions. We therefore conclude that fine mortars were made of different batches of lime and not at the same time. In the fine mortars, the inert material was marble powder.The important pigments of the painting are: Cyan is Egyptian blue, in the composition of which cuprorivaite crystals were found along with glassy material. Yellow pigment is yellow ochre of the mineral goethite, dark red is hematite, bright red is cinnabar and bright green is malachite.The painting technique which was  Iplied in the tomb is «fresco a’secco» using lime as binder. In the multilayer layers, and to depict the growth of the shadow, it is likely that an organic binder was used. The brown sample used for luminescence modeling was studied using FTIR spectroscopy. Proteinaceous material was detected in the sample, which may be related to the use of an organic adhesive material.

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 lumi-nescence (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.

Small masses of blue and red pigment found during the excavation of the temple of Uni in Marzabotto have been studied by employing XRF, FT-IR, and micro-Raman techniques. Thanks to these different spectroscopic techniques, the identification of red ochre and Egyptian blue pigments has been ascertained. The findings of Egyptian blue masses and the attestations of its use in the Etruscan area allow us to hypothesize its provenance, the trade carriers and the beginnings of circulation. The VIL technique has been applied on some architectural terracottas in the National Etruscan Museum of Marzabotto to investigate the presence of Egyptian blue, never attested before in the Etruscan Po Valley. The analysis permits to better understand the decoration pattern, the fabrication techniques and the specialised production of some tiles painted with Egyptian blue. Moreover, the study of polychromy on terracottas gives the possibility to make a realistic reconstruction of the decorative elements in the city.

Le collezioni museali italiane sono ricche di oggetti e manufatti prodotti nell'Antico Egitto. Lo studio di tali reperti riveste da sempre un particolare interesse e fascino ed è complicato dal fatto che sin dal XIX secolo la produzione di falsi e pastiche è stata molto diffusa. A causa di questo fenomeno nel corso dei secoli le collezioni si sono talvolta arricchite di falsi e di opere modificate di cui spesso diventa difficile stabilire quanto ci sia di autentico e quanto di manomesso. Discipline quali la chimica e la fisica offrono da molti anni un importante ausilio per riconoscere gli originali e per studiarne inoltre le tecniche esecutive e lo stato di conservazione. Recentemente sono state numerose le tecniche analitiche sviluppate per la diagnostica e lo studio dei materiali di interesse storico artistico e tra di esse rivestono una particolare importanza le tecniche non invasive, quelle, cioè, che permettono di ottenere importanti informazioni mantenendo l'integrità dell'opera e non necessitano, pertanto, il prelievo di campioni. Il presente lavoro illustra l’applicazione di alcune di queste tecniche su reperti egizi di Musei Italiani tra i quali il sarcofago femminile del Museo Archeologico di Asti risalente alla XXI Dinastia (1077-943 a. C.) e alcuni reperti del Museo Stibbert di Firenze: il coperchio del sarcofago antropoide in legno di Pakharu, databile alla prima metà della XXV Dinastia (tra il 725 e il 700 a. C.), il cosiddetto “pannello ligneo dipinto” realizzato unendo insieme su di un supporto ligneo entro cornice dorata e di un medesimo cartonnage risalente ad un periodo compreso tra la XXIII e la XXV Dinastia. Particolare spazio verrà riservato alla innovativa tecnica di imaging multispettrale Visible Induced Luminescence (VIL) e alle potenzialità che derivano dall’accoppiamento con altre tecniche non invasive più consolidate come ad esempio la Fluorescenza dei Raggi X.

Colours containing bright and saturated blue hues were popular for painterly effects in most of the Mediterranean cultures dating from the Bronze Age to the fall of the Roman Empire. Pigments providing the desired blue were produced from precious minerals such as azurite and lapis lazuli, but bright blue hues also came from pigments produced by merging other naturally occurring sources. This large group of synthetically-generated blue frits is referred to as Egyptian blue. Egyptian blue is a calcium copper tetrasilicate compound, a synthetic pigment made by heating a calcium compound (such as powdered limestone and sand rich in calcium carbonate) together with copper and quartz (fig. 1), although synthetic blue pigments based on cobalt are also known, so far mainly in Egypt (such as “Amarna-blue”). The hue of Egyptian blue pigments ranges from a saturated, almost black blue to light blue, bluish-green, and purple, each being dependent on the materials employed for its production and manufacturing process. Its material properties are crystal-like, resembling finely shattered glass. It ranges in saturation and brightness (which can be enhanced by secondary heating), and it has a relatively low covering power. It seems to have ceased being widely applied sometime after the fall of the empire, which added a certain mystery to it.

An analysis of paints found in ceramic sherd palettes from the 18th Dynasty (1548-1302 BCE) Pharaonic town on Sai Island in Upper Nubia using polarised light microscopy and infrared spectroscopy revealed pigments from the standard Egyptian repertoire: red and yellow ochres, Egyptian blue, calcite, gypsum, anhydrite, and the bright white huntite. Orange-yellow residues in ceramic sherds from the town were analysed using gas chromatography mass spectrometry (GC-MS) and were identified as Pistacia sp. resin, probably for use as incense. A dark organic substance from a vessel in the elite Pharaonic cemetery of the island was analysed using a second GC-MS method and was shown to be bitumen. Biomarkers in the bitumen indicate that its source may be the same as a sample from another Pharaonic town in Upper Nubia, suggesting a possible Nubian source. This is one of the earliest identifications of the use of bitumen in a funerary context in the ancient Nile Valley, and the furthest southern example yet analysed. Black fluids containing bitumen were used in Egypt as part of the process of mummification and for funerary anointing rituals; it is likely that the bitumen material at Sai was related to these practices.

Maya Blue is an unusual blue pigment consisting of a clay-organic complex of indigo and the unusual clay mineral palygorskite (also called attapulgite). Used on pottery, sculpture and murals from the Preclassic to the Late Colonial Period largely in Mesoamerica, blue was the color of sacrifice and ritual. Did the palygorskite used to make Maya Blue come from a restricted source in Yucatán like Shepard, Arnold, Arnold and Bohor believed, or did it come from widespread sources like Littmann argued? This article reports the results of a pilot study comparing INAA and LA-ICP-MS analysis of 33 samples of palygorskite collected from different parts of the Maya area. These data reveal that it is possible to discriminate source locations of the mineral, and that it should be possible to determine whether the palygorskite used to make Maya Blue came from widespread sources or was traded widely from a single or small number of sources.

Photo-induced luminescence is used in this study to excite Egyptian blue pigment so that a digital image can be recorded showing the exact location of the pigment within a piece of art. Control tests were run to find the optimal settings for the modified camera to be able to detect the pigment; this was followed by comparison tests between dark and light conditions, indirect and direct sunlight, and other minerals. Finally, the modified camera was used at the Ashmolean Museum to test twenty-five objects from different places and periods for the presence of Egyptian blue pigment.

Egyptian blue pigment was used over a 4000-year period in many cultures around the world and remained chemically consistent throughout this period. The way in which it was used has great historical value as conclusions can be drawn about the cultures that used it, contemporary manufacturing processes, and the trade routes of the ancient world which enabled the pigment to be so widely used without a significant change in its chemical makeup. Thus, the ability to detect the pigment where it is no longer visible to the human eye is of great interest to the archaeological and historical communities.

The results of the artefacts at the museum varied, but importantly, this study proved that contrary to previous studies, dark room conditions need not be observed to obtain good results using this technique. Some limitations of the technique were observed, such as the detection limitations of the modified camera to properly detect the pigment which include extreme weathering, and possibly the use of binding medium, or conservation techniques, though future study could further illuminate this issue.

The microstructure and chemical composition of blue cakes, found during the archaeological excavation
of the Ayanis fortress (Eastern Anatolia, Turkey), have been investigated by means of scanning electron
microscopy combined with energy dispersive spectrometry (SEMeEDS), X-ray diffraction (XRD), micro-
Raman (m-Raman) and optical microscopy (OM) techniques. The analysis of the Ayanis cakes has shown
the presence of Egyptian blue (i.e. CuCaOSi4O10, cuprorivaite), as the major component, intermixed with
minor amount of other phases such as partially reacted quartz grains, an adherent glass phase and
copper oxides. Since the finding of Egyptian Blue in Turkey has been never reported so far, great attention
has been paid to its characterisation. The micro-chemical and micro-structural investigations of the
Ayanis cakes have allowed a further insight into the manufacturing process and into the sources of the
starting materials. The results of the characterisation have revealed some significant differences with
respect to Egyptian blue cakes found in Egypt and Mesopotamia, as for instance the absence of tin
excluded the use of bronze scraps or filings in their preparation differently from those produced in Egypt
and Mesopotamia. Furthermore, some peculiarities of Egyptian blue found in Ayanis, as the detection of
zinc in the cakes, allow to put forward the hypothesis of a local production considering that a large part
of the bronze artefacts found at the Ayanis fortress is characterised by the presence of zinc as minor
alloying element.

Since its beginnings, the study of Egyptian antiquities has generated interest and fascination and the widespread production of fakes and pastiches since the nineteenth century has been a complicating factor in its development. Due to such a common phenomenon, collections have acquired fakes together with original pieces throughout the centuries, often retouched in modern times but so similar to the genuine ones as to make it hard to distinguish them. In the last few decades, chemistry and physics have helped in this research by providing important support in the identification of genuine artifacts, and in the study of their state of conservation, as well as the techniques used to assemble the pieces. Recently, several analytical techniques have been introduced for the diagnostic study of artworks as well as for archaeological finds. Among them, the most important are those that are non-invasive. These latter techniques are highly successful in providing useful data without altering the original state of the object. In this paper, we present our current research on two cases in which Visible-Light Induced Luminescence (VIL) was applied: the anthropoid wooden coffin of Pakharu, dating to the first half of the Twenty-fifth Dynasty and the "painted wooden board", (Twenty-second to Twenty-fifth Dynasties), which was made by reassembling two different fragments of the same cartonnage onto a wooden support mounted within a golden frame.

Maya Blue, a nano-structured clay-organic complex of palygorskite and indigo, was used predominantly before the Spanish Conquest. It has fascinated chemists, material scientists, archaeologists and art historians for decades because it is resistant to the effect of acids, alkalis, and other reagents, and its rich color has persisted for centuries in the harsh tropical climate of southern Mesoamerica. One of its components, palygorskite, is part of modern Maya indigenous knowledge, and ethnohistoric and archaeological data suggest that its modern sources were probably utilized in Prehispanic times. Yet no direct evidence verifies that palygorskite was actually mined from these sources to make Maya Blue. Here we characterize these sources compositionally, and compare our analyses to those of Maya Blue from Chichén Itzá and Palenque. We demonstrate that the palygorskite in most of these samples came from modern mines, providing the first direct evidence for the use of these sources for making Maya Blue. These findings reveal that modern Maya indigenous knowledge about palygorskite, its mining, and its source locations, is at least seven centuries old.

This paper examines the production technology of Egyptian blue, an ancient artificial pigment, through the investigation of an unsuccessfully produced pellet derived from the Hellenistic production site of Kos (Dodecanese, Greece). This heterogeneous material was investigated by a combination of laboratory and synchrotron radiation-based (SR) techniques: scanning electron microscopy coupled with energy-dispersive X-ray spectrometry, micro-Raman spectroscopy, high-resolution SR micro-X-ray fluorescence spectroscopy, and SR micro-X-ray absorption near-edge structure spectroscopy (XANES), at the ID21 beamline of the European Synchrotron Radiation Facility. Principal component analysis of a large dataset of 171 micro-XANES spectra acquired on the archaeological samples and on a series of reference copper compounds emphasizes high variations of XANES features due to different speciation and also orientation effects, as demonstrated by the simulated XANES spectra. The results indicate that, rather than inadequate firing temperatures that could have led to the reddish cuprite (Cu2O), unsuccessful production may occur due to the use of inappropriate starting materials, which contain an unusually high iron content. The contextual interpretation underlines the intertwined relationship between the production of Egyptian blue and metallurgy.