An Innovative Noninvasive and Nondestructive Multidisciplinary Approach for the Technical Study of the Byzantine Wall Paintings in the Enkleistra of St. Neophytos in Paphos, Cyprus
To date, only a small number of noninvasive techniques and very few entirely portable instruments are available for in situ applications in cultural heritage. Among these are the recently developed field ultraviolet/visible/near infrared (UV/Vis/NIR) spectrometers that allow onsite chemical and mineralogical characterization of materials based on chemical fingerprinting (Wisseman et al. 2002); and the hand-held X-ray fluorescence (XRF) spectrometers that offer information at the atomic level (elemental composition) (Aloupi et al. 2000). Combined with broadband imaging using digital cameras and optical filters or with miniaturized multispectral imaging spectroscopic systems that operate at different wavelengths within the ultraviolet and infrared regions of the electromagnetic spectrum (Fischer and Kakoulli 2006), portable instruments have become indispensable to scientific investigations, whether in the field, the museum, or the laboratory.
This research introduces the development and application of an innovative multidisciplinary approach for the technical study of the twelfth-century wall paintings in the Enkleistra ("hermitage" or "place of reclusion") of St. Neophytos in Paphos, Cyprus (Figure 1). This approach harnesses the analytical capabilities of a portable UV/Vis/NIR spectrometer combined with those of a portable XRF and digital broadband spectral imaging in a wide spectral range. This research is part of a larger-scale project for the study and interpretation of the paintings in the Enkleistra, based on combined noninvasive and nondestructive scientific methods of investigation in the interface of materials science and art from the macroscopic to the nanoscale.
The goal is to study the technique and materials of the different painting schemes and other painterly interventions in the Enkleistra and to assist in the classification and attribution of the ambiguously dated paintings (Mango and Hawkins 1966; Nicolaides 1996; Winfield 1971). In addition, it fosters cutting-edge interdisciplinary research and evaluates the potential of combined field imaging and spectroscopic techniques for the study of in situ wall paintings. The broader aim is to put forward hypotheses about the significance of technical findings for understanding the relationship between stylistic patterning and technological production in the context of the religious and social structure and organization of monastic communities in the twelfth century in Cyprus, immediately prior to the Latin occupation and during the transitional period after the connection with the Empire had been severed; to make a technical stylistic analysis of the paintings of the Enkleistra in relation to other twelfth-century paintings in Cyprus; to re-examine the maniera greca and to re-evaluate its role and influence on western art (Panofsky 1960; Kitzinger 1966); and to identify cross-regional patterns of trade and intercultural exchanges between the capital and other parts of the Byzantine empire.
Based on two onsite campaigns for the scientific investigation of the paintings, the first in September 2008 and the second in May/June 2009, in this report we will not attempt to support or contradict previous art historical studies on the attribution and chronology of the paintings. Instead, the results presented here will discuss in general terms the techniques and materials of the paintings in the Enkleistra without going into details about the individual schemes of painting and attributions.
Geographical and Chronological Outline
The geographic location of Cyprus at the crossroads of Europe, Asia, and Africa, the meeting point of great civilizations reflects the factors that have influenced the course of the island's history and its rich cultural heritage.
As early as the first century A.D., the Roman Governor Sergius Paulus converted to Christianity and Cyprus became the first country in the ancient world governed by a Christian ruler. The spread of the Christian faith slowly created a different attitude towards life, and it was not long before the pagan adoration of Aphrodite and Apollo became the adoration of the Virgin and Child. Following the division of the Roman Empire, Cyprus became part of Byzantium with Constantinople as its capital. The political history of the island was tranquil until the repeated Arab invasions of the seventh century. The most dramatic period of the Cypriot history, however, was the second half of the twelfth century, marked by the devastation of the island by Renaud de Châtillon in 1155/6 and by the cruel and scandalous administration of Isaac Comnenus (1185–91). In 1191 Cyprus was conquered by Richard I of England, who sold the island to the Templars, who in turn sold it to Guy de Lusignan. The Lusignan kings ruled Cyprus until 1489, when the control of the island passed to the Venetians. The style and manner of the paintings of the Enkleistra of St. Neophytos clearly reflects this eventful history.
St. Neophytos: His Life and Work
St Neophytos Enkleistros ("The Recluse") was born in 1134 at Lefkara, a small town in Cyprus near the city of Larnaca. He was the son of Athanasios and Eudoxia, one of eight children. At the age of 17 he chose the monastic life, and for five years remained at the St. Chrysostom monastery near Kyrenia, cultivating the land and teaching himself how to read and write. Two years after he completed his duties as a disciple, although he had attained the position of assistant sacristan, he left for Jerusalem in search of the solitary life. His search for enlightenment failed and Neophytos returned to Cyprus, intending to leave shortly thereafter, this time for Mt. Latmos in Asia Minor. However, his second attempt failed once again. Upon embarking, he was for unknown reasons arrested and, when he was finally released from prison, he decided to become an ascetic at the hilly area above Paphos. He departed for his place of reclusion on June 24, 1159 and set immediately to building his cell, by enlarging and modifying an already existing cell. He gradually dug his abode into a complex, comprised primarily of three caves (what is today the Cell, the Bema and the Naos), which he dedicated to the Holy Cross (). Based on his statement that he "set up an altar for divine service so as not be sundered from the holy communion of the body and blood of Christ,"Typikon, chap. 5, p. 8; Mango and Hawkins 1966, 133. the cell and what is today the Bema (with an altar) were the first caves to be excavated between September 1159 and September 1160.
His fame soon spread and in 1170 he was forced by the bishop of Paphos to accept a disciple. He started a monastery and composed the rules which he called "Typike Diatheke." It was the same year that "the structures of the Enkleistra began to be extended and adorned and the whole length of the cliff was excavated for the erection of cells."Ibid. This extension phase seems to have included the Refectory, which is at the same level of the Enkleistra, and which is also adorned with paintings (Mango and Hawkins 1966, 133–134). According to Neophytos's own testimony, however, it was not until 1183 that the Naos was excavated (Mango and Hawkins 1966, 194).
Neophytos proved himself to be a talented writer, composing not only his biography and the rules of his monastic community, but also an account of the conquest of Cyprus by Richard I in 1191 and several theological treatises. However, the increasing number of pilgrims led him to dig another cave above the first one (the New Zion), in search of solitude and inner peace. This latter cave was completed by the end of 1197, the same that the interior paintings of the Naos were created. According to written testimonies, the Enkleistra was painted in 1183 by Theodore Apseudes, while the final phase of the paintings, mainly in the Naos, belonged to a different phase, after 1197. There are important stylistic differences between the earlier and the later wall painting schemes of the twelfth century. Whereas the earlier style is characterized by the "rococo" manner of painting (Figure 3), the later style is more austere and could be characterized as "monastic" or "Comnenian provincial" and "linear" (Figure 4). The paintings of the Enkleistra were restored in 1503 through the commission of another monk Neophytos (Mango and Hawkins 1966).
The Enkleistra and Its Wall Paintings
The wall paintings in the Enkleistra of St. Neophytos are among the most important and celebrated twelfth-century Byzantine paintings in Cyprus (Stylianou and Stylianou 1985; Mango and Hawkins 1966). The unusual rock-cut structure of the Enkleistra and the unique surviving painting of high artistic quality impress visitors, pilgrims, and scholars. The scenes depicted include the Crucifixion (painted multiple times in different areas of the Enkleistra), the Deesis, the Annunciation, and scenes from the Passion. One of the most unusual and spectacular scenes, however, is depicted on the west face of the east bay where there is an impressive painting of the aspirations of the monk: St. Neophytos is depicted among the archangels Michael and Gabriel who hold him by the shoulders (Figure 5). An inscription explains the picture: "I fervently pray that I may indeed be enrolled among the angels by virtue of my habit."For a detailed description of the iconography of the paintings in the Enkleistra see Mango and Hawkins 1966 and Stylianou and Stylianou 1985.
Chronology of the paintings
Based on the extensive description and attributions of the paintings in the Enkleistra by Mango and Hawkins (193), they can be grouped as follows:
- The paintings in the Cell and Bema
- The paintings in the Naos
- The paintings in the Refectory (first layer)
- The paintings in the Narthex, the second layer in the Refectory, and the repairs of 1503.
The dates for the paintings in the Cell are established by St. Neophytos—"in the twenty-fourth year of my confinement the Enkleistra was painted throughout"—and by the inscription of the painter, Theodore Apseudes, which provides the date 1182/83. Based on the stylistic similarities with the less complex paintings in the Bema, mainly those of the east bay, according to Mango and Hawkins (194), these dates refer to the extended painting phase visible on most of the walls in the cell.
For the paintings in the Naos (first scheme), the terminus post quem was established as the year 1197 when St. Neophytos moved to the New Zion. Mango and Hawkins (201) date these paintings soon after the construction of the Naos in 1197, around 1200, rather than later as suggested by other scholars. The paintings of the Refectory (first scheme) are believed to be contemporary to those of the Naos, although attributable to a different painter or workshop (Mango and Hawkins 1966, 202).
The only established date for the post-Byzantine paintings in the Enkleistra is the inscription in the Naos with the date 1503. Mango and Hawkins (202–03) have attributed the Pantokrator depicted on the ceiling of the western bay in the Bema to the same painting phase based on stylistic grounds. The paintings in the Narthex, on the other hand, were compared with those in the katholikon and dated to around 1500. Similarly, the second-phase paintings in the Refectory (also post-Byzantine) were also considered as contemporary and dated close to 1500 (Mango and Hawkins 1966, 203).
Methodology, Principles of Methods and Experimental Set-up
Having completed a thorough visual inspection of the paintings (paint layers and plasters), the paintings were documented for archival and diagnostic purposes with digital broadband photography using a broad spectral range, from the ultraviolet (UV) to the near infrared (NIR) region. Visible, UV-induced, and NIR reflectance and luminescence images were captured. Subsequent to the diagnostic imaging, the paintings were further analyzed with the pUV/Vis/NIR reflectance spectrometer for molecular and mineralogical characterization and with the pXRF spectrometer for elemental identification of the inorganic components. The paintings were systematically documented and analyzed; measurements were taken from all painting phases visible in the Cell, Bema, Naos, and Narthex, paying attention to analyze methodically areas of the paintings with similar hues for comparanda. The blue and green backgrounds, the flesh tones, the white/grey and red-brown colors of the garments and the red borders framing each scene were consistently analyzed.
pUV/Vis/NIR Reflectance Spectroscopy
The primary tool selected for this investigation is a pUV/Vis/NIR spectrometer, which provides inexpensive and quick mineralogical characterization and organic molecular identification of the constituent materials in the paint layers and on the surface without having to take a sample. This study used the newly developed FieldSpec® 3 by Analytical Spectral Devices Inc (ASD). FieldSpec® 3 has high spectral resolution (3 nm @ 700 nm and 10 nm @ 1400/2100 nm) and wide spectral range between 350–2500 nm. These features allow the collection of both reflectance and visible fluorescent measurements from the surface of ceramics or from micro-cross sections. FieldSpec® 3 is highly portable, user-friendly, and allows a fast, inexpensive, and flexible method for spatially resolved analysis of the paintings. It can acquire ten spectra per second for the entire 350–2500 nm range. The flexible spot size analyzer for contact analysis facilitated the systematic study of specific areas.
X-ray fluorescence spectroscopy is a noninvasive technique widely used for the elemental characterization of materials and has found extensive application for the study of paintings. The versatile capabilities of the pXRF have extended its use to in situ applications for the preliminary characterization, classification, and sorting of a variety of objects in museum collections, as well as for the analysis and sourcing of pigments in wall paintings (Philips and Speakman 2009; Papageorgiou and Liritzis 2007; Craig et al. 2007; Williams-Thorpe et al.> 1999; Morgenstein and Redmount 2005).
The Tracer Ⅲ–Ⅴ, a portable XRF spectrometer from Bruker was used for the analysis of the paintings at the Ekleistra of St. Neophytos. The pXRF was operated at 40Kev and 1.35 mA. The acquisition time was set to 60s.
Broadband Digital Imaging
Broadband digital diagnostic imaging employing primarily visible (diffuse and raking light), UV-induced visible fluorescence, and UV and NIR reflectance and luminescence photography, as well as reconstructed false-color trichromatic composite spectral images (through post-capturing processing) provided complementary and important information on surface characteristics and enhanced compositional heterogeneities. The Fujifilm IS-1, a 9.0 megapixels digital camera was used; its CCD sensor can capture adequately between 400 and 900 nm. Two different types of illumination were tested for digital photography in the field. For visible and near infrared reflectance photography two General Electric Halogen lights (150 watt each) were used with a broad emission from the ultraviolet to the infrared parts of the electromagnetic spectrum. For ultraviolet-induced visible fluorescence photography, three Arachnid 5mm UV LED handheld blacklight flashlights were employed, which emit in the long wave ultraviolet region (365nm-390nm). Aperture Priority mode has been the preferred setting for NIR documentation, while focusing was done manually to prevent the lens' focus from shifting.
For visible light photography, different filters were tested. The best results were obtained using the X-NiteCC1 without additional filtering. For NIR reflectance photography the paintings were illuminated with the two halogen lights at a 45 degree angle from the paintings, while three Maxmax long pass filters (715nm, 780nm and 830nm) were used to capture the images. Complementary information was obtained with the use of these different filters based on the spectral reflectance of the area photographed. Ultraviolet reflectance photography involved the use of ultraviolet illumination (using the Arachnid 5mm UV LEDs) combined with specific filters that transmit in the ultraviolet region of interest (similar to the emission wavelength). Although the sensitivity of the camera's sensor is in the range of 400 to 900nm, as the excitation source used had its highest emission peak at 390nm, the images captured through this technique correspond primarily to the reflectance in the blue end of the visible spectrum. For UV-induced visible fluorescence, the paintings were illuminated again with the Arachnid 5mm UV LEDs, while the camera sensor was filtered with the X-NiteCC1. For luminescence photography in the NIR, the long pass 715nm NIR filter was used instead.
Composite images were reconstructed by recombining three monochromatic pictures taken at specific wavelengths. For false-color infrared, a picture captured in the infrared was combined with the red and green of the visible, whereas for false-color ultraviolet, a UV reflectance image was combined with the blue and green.
Results and Discussion
Preliminary results from the combined noninvasive investigations integrating imaging and in situ spectroscopic analyses suggested that the paintings in the Enkleistra belong to various painting phases between 1160 (soon after the completion of the excavation of the Cell) and the middle of the eighteenth century (contemporary to the opening of the door in the east wall of the Cell). Within this time frame, there are several other painting phases, the most distinctive ones being the painting scheme by Theodore Apseudes of 1183, concentrated mainly in the Cell and the Bema; the post-1197 painting phase found mainly in the Naos; the later remodeling/redecoration of the Enkleistra by the monk Neophytos in 1503 that occurs principally in the Nave and the Bema; and the paintings in the Narthex displaying two painting schemes, the earlier visible only on the west wall (above the entrance door to the Naos close to the vault). In the cell alone, there are at least five individual painting phases that can be discerned, two of which (seen on the east and south wall of the Cell) clearly predate the 1183 phase (Mango and Hawkins 1966; Wharton Epstein 1981), while two others, the painting of St. Andrew Salos on the south wall and another later phase on the east wall that could be contemporary to the opening of the door, postdate the paintings by Apseudes.Further investigation is required to establish if the panel with St. Andrew Salos was painted before or after the 1183 phase. In the Bema, there is also evidence of a pre-1183 painting phase (most likely part of an original incomplete decoration of the Bema) visible on the east and south walls, and there is clearly at least one other painting phase, and perhaps more, in the Bema that has not been mentioned by Mango and Hawkins.
Technique and Materials of the Paintings in the Enkleistra
Based on visual observation and scientific data, two different techniques were used for the execution of the paintings in the Enkleistra: the fresco and the secco techniques. Fresco technique refers to any painting executed on a moist lime-rich (calcium hydroxide) plaster layer. The pigments are commonly applied with water, and are fixed by the formation of a carbonate lattice during a chemical reaction occurring with the setting of the lime.
Ca(OH)2 + CO2 ➞ CaCO3 + H2O↑
Slaked lime Carbonated lime
During this chemical reaction there is a loss of water, which causes contraction and cracking, and therefore when lime is used as a plaster it is always mixed with organic or inorganic aggregates. In a fresco technique, the plaster is generally applied "patch by patch," each patch being the area of painting which could be completed before the plaster dried. These small sections of plaster are usually called giornata(e), Italian for "day(s)." In contrast, the secco ("dry") technique involves the use of any surface onto which the pigments are fixed by using an organic binding medium.
In the Enkleistra, the fresco technique can be clearly seen in the image of St. Andrew Salos painted on the south wall of the Cell. The panel was executed on an individual giornata of plaster with pigments compatible to the fresco technique. Conversely, the scene of the Crucifixion painted on the same wall was completed entirely in the secco technique; the painting was executed over a thin whitewash layer applied over a pre-existing painting. The pigments were mixed and applied on the wall using an organic binding medium, most likely a drying oil and/or egg tempera or glue.The analysis and interpretation of results are still in progress.
Various natural mineral pigments (both local and exotic), as well as artificially produced inorganic pigments were identified in the wall paintings by means of pXRF and pUV/Vis/NIR spectroscopy. The local mineral varieties included mainly red and yellow ochre (Figure 6) (haematite – iron [III] oxide and goethite – iron [III] oxyhydroxide), umber (iron [III] oxide and manganese oxide), green earth (celadonite, an iron [II][III] silicate pigment), calcium carbonate white, and possibly white clay. The foreign natural inorganic pigments included lapis lazuli (Figure 6), consisting mainly of lazurite, diopside and pyrite minerals (Plesters 1986; Gaetani et al. 2004), cinnabar (mercuric sulfide), and an arsenic-containing pigment, perhaps orpiment or realgar (arsenic sulfide). The artificially produced inorganic pigments included lead white (basic lead carbonate) and minium or red lead (lead tetroxide). The pigments seem to have been used pure or in mixtures and were applied in a single or multiple layers. Diagnostic for differentiating the painting phases were the green and the flesh paints, while the analysis of the blue paint pointed to the consistent use of lapis lazuli (in all painting phases excluding the post-Byzantine), whereas the bright red paints varied from pure cinnabar to mixtures or superimpositions with red lead (Figure 7). The yellow paints consisted mainly of yellow ochre, while the brown-reds consisted of different hues of red ochre, yellow ochre, and umbers applied pure or in combination with each other.
Thin metal foils of alloys (or electrons) were also identified in the paint layers, and more particularly in the halos to give a metallic glitter. These showed traces of gold (Au) and silver (Ag). The gold/silver leaf was applied over a layer of yellow ochre presumably using glue or a mordant (further investigation is required).
During the documentation of the paintings, different paint alterations were observed on both the earlier (twelfth century) and later (post-Byzantine) schemes. The most common alteration pattern documented was the darkening of the bright red paint layers. A similar grey discoloration was also observed in some areas of the blue and the green paint layers. These color changes in the paint layers are currently under investigation.
The paintings show evidence of a number of previous interventions, some of which have been recorded in the literature (Mango and Hawkins 1966). Paraffin wax was identified on the surface of the paintings, particularly those in the Cell, while an Acryloid (a methyl methacrylate copolymer), possibly Paraloid B72, seems to have been applied over the surface of almost all the paintings. One section of the painting decorating the tomb in the Cell (on the west wall) was completely removed from the rock-cut surface by the conservators of the Department of Antiquities in Cyprus during a conservation intervention, as the painting showed severe delamination and disintegration. It was, however, later re-attached after it had first been consolidated on an artificial support (pers. comm. Hadjistephanou 2009). In addition, the paintings also show old and new edging repairs, filled injection holes (possibly used to apply a grout), plaster repairs, and extensive retouching.
Reflections on the Paintings in the Enkleistra
The painting schemes in the Enkleistra are more complex than originally estimated by those primarily employing art historical stylistic interpretations (Stylianou and Sylianou 1985; Mango and Hawkins 1966). With the help of special photographic techniques and illumination methods, distinctive features of the painting techniques, such as the treatment of the plasters and ground layers, the application of brush strokes, and the execution of the underdrawings, revealed the manner of painting, which together with the chemical analysis of the paint layers, will contribute to the attribution of the paintings. The presence of certain pigments and organic binding media offer some clues to the technique and previous experience of the painter(s). The extensive use of lead-containing pigments, for example, suggests that the painter or painters were more familiar with icon-painting techniques on wood, rather than wall painting techniques. In addition, these pigments and binding media could also help in dating the paintings.
Without doubt, the results from the noninvasive analysis conducted in the Enkleistra, although not conclusive, will shed new light on the different schemes and help to establish their relation to each other. So far, the paintings show some individual characteristics and different techniques in their execution. Both local and foreign natural minerals are present, the sourcing of which will assist further in their attribution. Expensive pigments such as cinnabar and lapis lazuli were extensively used, as well as gold and silver metal foils. Current investigations to identify fine similarities and dissimilarities in chemical composition of materials and the techniques of execution will clarify our understanding on the paintings decorating the Enkleistra.
Some considerations about the noninvasive in situ analysis of wall paintings
Wall paintings like other types of work of art are often quite complex, consisting of one on more plaster layers, multiple paint layers of pure pigments or mixtures, metal foils and surface varnishes. A part of a building or a monumental structure that is commonly exposed to adverse and uncontrolled environmental conditions, wall paintings often show patterns of paint discoloration and darkening, plaster and paint disintegration, delamination, exfoliation, and other structural decays. The use of portable field instruments employed for the characterization of materials that yield results at surface and subsurface level can therefore provide essential and vital information on the chemistry of materials (organic and inorganic) and can reveal and identify patterns of materials alteration, as well as foreign artifacts. In this study, of significant importance highlighting the contribution of portable instrumentation, was the identification of lapis lazuli, possibly brought to Cyprus from Afghanistan through Constantinople, and the detection of organic materials on the surface of the paintings, which are often difficult to identify even with highly sophisticated laboratory analytical techniques (Chiavari et al. 1999). The organic spectral signatures of wax and Acryloid, probably corresponding to surface protective coatings, were also seen fluorescing under UV-induced illumination. However, there are still some limitations to the use of portable instruments: in specific cases, important information that can provide clues to answer complex questions on the technology, provenance, and dating of a work of art can only be determined with micro-sampling and spatially resolved laboratory analysis of the stratigraphic samples at the molecular and nanoscales.
Major contribution of this project
Whereas previous studies of the techniques of Cypriot wall paintings have concentrated on the relatively late paintings of Askas (fifteenth and sixteenth centuries) and Monagri (eighteenth century) (Frieden 1997; Howard 1992; Kakoulli 1994), with the exception of the recent study of the contemporary Byzantine paintings at the church of the Virgin Phorviotissa at Asinou (Kakoulli et al., forthcoming), the study of the paintings in the Enkleistra of St. Neophytos focuses on the more important but less well studied period of the twelfth century. This study is therefore pivotal for understanding the native artistic traditions that survived to the end of the eleventh century in Cyprus, and the direct and indirect influence of the capital in the twelfth century.
Further research will involve the thorough and systematic processing of the data collected using the integrated approach of combined techniques during the onsite noninvasive investigation of the painting. This will enable us to identify each phase of painting based on its technical attributes and materials, and to map the spatial distribution of each phase in the Enkleistra. The results will be further correlated with Byzantine and Medieval treatises (Hermeneia 1974) on techniques, and with other technical studies of contemporary paintings (Nadolny 2001; Plesters 1963; Schwartzbaum 1986; Winfield 1969–70).
Micro-sampling of important key paint layers will also be conducted to provide information for the sourcing of materials, dating, and attribution of the paintings. A spectral library of UV/Vis/NIR reflectance and XRF spectra of the original paint layers will also be compiled and will be available on line through a dedicated website.
We are most grateful for the generous support of the Dumbarton Oaks, which made this important pilot project possible through the award of a Project Grant in Byzantine Studies during 2008/09, and to the Council of Research at UCLA that granted Prof. Kakoulli a faculty award. We also wish to thank all the monks and staff of St. Neophytos monastery, and particularly Father Alexios, for his hospitality and continuous support during the duration of the onsite investigations and beyond; the Department of Antiquities of the Republic of Cyprus, for the permit to study the paintings in the Enkleistra of St. Neophytos; and Dr. Jenny Hällström, postdoctoral fellow at UCLA, for her invaluable assistance with the scientific investigations during the field campaign in May/June 2009.
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