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DOI: 10.1007/s00339-006-3557-5 Appl. Phys. A 83, 709–717 (2006) Materials Science & Processing Applied Physics A e. pavlidou 1 m. arapi 2 t. zorba 1 m. anastasiou 1 n. civici 3 f. stamati 4 k.m. paraskevopoulos 1, Onoufrios, the famous XVI’s century iconographer, creator of the “Berati School”: studying the technique and materials used in wall paintings of inscribed churches 1 Physics Dept., Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece 2 Institute of Monuments of Culture, Tirana, Albania 3 Institute of Nuclear Physics, Tirana, Albania 4 Institute of Popular Culture, Tirana, Albania Received: 15 June 2005/Accepted: 18 January 2006 Published online: 11 March 2006 • © Springer-Verlag 2006 ABSTRACT The study of the materials and techniques employed for wall painting, complementing the information from histori- cal and aesthetic data, contributes to the integrated knowledge of the iconographer and his period. In the 16th century, re- garding the iconography in the former Byzantine area, besides the School of Crete and Francos Catelanos and his school, a third artistic personality who also created his own school, Onoufrios, appeared in central Albania and expanded his ac- tivity as a painter to northern Greece as well as nearby areas, such as Ohrid. Inscriptions documenting the works of Onoufrios are found in some of the churches that he decorated with wall paintings: “St. Apostles” (1547) Kastoria Greece, “St. Nico- las” Shelcan Albania, “St. Paraskevi” (1554), Valsh Albania, while are attributed to him the church of “St. Theodores” in Be- rati, Albania (before 1547) and others. He is one of the best icon painters of the whole Balkan region, and the best painter that has ever worked in Albanian territory. Onoufrios managed to combine the local painting tradition with the best tradition of the eastern (Paleologian) and western (Italian) schools, re- sulting in a realistic and natural depiction. He is the creator of the “Berati School” that expanded to other parts of the penin- sula. His individual character can be distinguished in the work of his students: his son Nikolaos (who inherited his style in painting), Onoufrios from Cyprus, etc. Based on careful ob- servations, we extracted number of paint samples from wall paintings of three of the above mentioned churches. Ground and paint layers were examined using micro-FTIR, Optical Mi- croscopy, TXRF and SEM-EDS, to characterize materials and methods used by the artist to create these works. Our findings in each church are discussed and compared with the others in order to understand how and with what material and resources the painter worked and how he developed his technique. The pres- ence of calcium carbonate as the main component in all FTIR measurements points to a fresco technique. Pigments like red and yellow ochre, carbon black, green earth, calcium carbonate are used in all cases. The use of gypsum in the plaster construc- tion is characteristic. The deterioration of the wall paintings due to environmental effects – different in every church – is also examined. PACS 33.20.Ea; 68.37.Hk Fax: +30 2310 994301, E-mail: [email protected] 1 Introduction In the 16th century, the iconography in the former Byzantine area, were well known the school of Crete, and Francos Katelanos and his school. The same period, a third artistic personality who created his own school too, Onoufrios (Onoufrios, according to his inscriptions, or Onoufri in Al- banian language), appeared in central Albania, expanding his activity as a painter to other parts of the Balkan peninsula. He managed to combine the local painting tradition with the best tradition of the eastern (Paleologian) and western (Ital- ian) schools, resulting in a realistic and natural drawing of strictly Byzantine subjects together with a degree of individ- uality in facial expression. Biographical data about Onoufrios are obtained from the inscriptions in some of the churches that he decorated with wall paintings. His date of birth can be placed at the beginning of the 16th century, and he was probably born in the region of Berat or Elbasan (Neokastro). From the content of his inscrip- tions, one can deduce that he also received a Greek education. Around 1547 he must have become a priest and later probably, due to his great contribution as an iconographer, he graduated to a priest-in chief (protopapas) in Elbasan. By 1578 he had ei- ther died or was very old as the wall-paintings of the church of “St. Mary Blacherna” are signed by his son Nikolaos [1, 2]. At the beginning of the 16th century, the long period of struggle of the Albanians headed by George Kastrioti against the Ottomans came to an end with the fall of Durresi (1501). The country was almost destroyed and the economical situ- ation was dire. The Ottomans were trying to impose – as in all of their conquests – their rules, and among others a strong campaign began with the aim of converting the population to Islam. In the framework of this campaign, the construction of big Christian religious buildings with visible Christian signs was forbidden. Although the campaign was successful up to a certain degree in the cities, most of the population, espe- cially those people living in the countryside, opposed strongly this campaign by preserving their Christian religion. Due to this situation, Onoufrios worked in simple, small churches with no architectural value, situated in small and remote vil- lages. Most of them were rebuilt on the foundations of older ruined churches. All of them are single-aisle basilicas with no dome, no belfry and very few differences from each other. From the outside they resemble normal houses.

Onoufrios, the famous XVI’s century iconographer, creator of the “Berati School”: studying the technique and materials used in wall paintings of inscribed churches

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Page 1: Onoufrios, the famous XVI’s century iconographer, creator of the “Berati School”: studying the technique and materials used in wall paintings of inscribed churches

DOI: 10.1007/s00339-006-3557-5

Appl. Phys. A 83, 709–717 (2006)

Materials Science & ProcessingApplied Physics A

e. pavlidou1

m. arapi2

t. zorba1

m. anastasiou1

n. civici3

f. stamati4

k.m. paraskevopoulos1,�

Onoufrios, the famous XVI’s centuryiconographer, creator of the “Berati School”:studying the technique and materialsused in wall paintings of inscribed churches1 Physics Dept., Aristotle University of Thessaloniki, 54124 Thessaloniki, Greece2 Institute of Monuments of Culture, Tirana, Albania3 Institute of Nuclear Physics, Tirana, Albania4 Institute of Popular Culture, Tirana, Albania

Received: 15 June 2005/Accepted: 18 January 2006Published online: 11 March 2006 • © Springer-Verlag 2006

ABSTRACT The study of the materials and techniques employedfor wall painting, complementing the information from histori-cal and aesthetic data, contributes to the integrated knowledgeof the iconographer and his period. In the 16th century, re-garding the iconography in the former Byzantine area, besidesthe School of Crete and Francos Catelanos and his school,a third artistic personality who also created his own school,Onoufrios, appeared in central Albania and expanded his ac-tivity as a painter to northern Greece as well as nearby areas,such as Ohrid. Inscriptions documenting the works of Onoufriosare found in some of the churches that he decorated with wallpaintings: “St. Apostles” (1547) Kastoria Greece, “St. Nico-las” Shelcan Albania, “St. Paraskevi” (1554), Valsh Albania,while are attributed to him the church of “St. Theodores” in Be-rati, Albania (before 1547) and others. He is one of the besticon painters of the whole Balkan region, and the best painterthat has ever worked in Albanian territory. Onoufrios managedto combine the local painting tradition with the best traditionof the eastern (Paleologian) and western (Italian) schools, re-sulting in a realistic and natural depiction. He is the creator ofthe “Berati School” that expanded to other parts of the penin-sula. His individual character can be distinguished in the workof his students: his son Nikolaos (who inherited his style inpainting), Onoufrios from Cyprus, etc. Based on careful ob-servations, we extracted number of paint samples from wallpaintings of three of the above mentioned churches. Groundand paint layers were examined using micro-FTIR, Optical Mi-croscopy, TXRF and SEM-EDS, to characterize materials andmethods used by the artist to create these works. Our findings ineach church are discussed and compared with the others in orderto understand how and with what material and resources thepainter worked and how he developed his technique. The pres-ence of calcium carbonate as the main component in all FTIRmeasurements points to a fresco technique. Pigments like redand yellow ochre, carbon black, green earth, calcium carbonateare used in all cases. The use of gypsum in the plaster construc-tion is characteristic. The deterioration of the wall paintings dueto environmental effects – different in every church – is alsoexamined.

PACS 33.20.Ea; 68.37.Hk

� Fax: +30 2310 994301, E-mail: [email protected]

1 Introduction

In the 16th century, the iconography in the formerByzantine area, were well known the school of Crete, andFrancos Katelanos and his school. The same period, a thirdartistic personality who created his own school too, Onoufrios(Onoufrios, according to his inscriptions, or Onoufri in Al-banian language), appeared in central Albania, expanding hisactivity as a painter to other parts of the Balkan peninsula.He managed to combine the local painting tradition with thebest tradition of the eastern (Paleologian) and western (Ital-ian) schools, resulting in a realistic and natural drawing ofstrictly Byzantine subjects together with a degree of individ-uality in facial expression.

Biographical data about Onoufrios are obtained from theinscriptions in some of the churches that he decorated withwall paintings. His date of birth can be placed at the beginningof the 16th century, and he was probably born in the region ofBerat or Elbasan (Neokastro). From the content of his inscrip-tions, one can deduce that he also received a Greek education.Around 1547 he must have become a priest and later probably,due to his great contribution as an iconographer, he graduatedto a priest-in chief (protopapas) in Elbasan. By 1578 he had ei-ther died or was very old as the wall-paintings of the church of“St. Mary Blacherna” are signed by his son Nikolaos [1, 2].

At the beginning of the 16th century, the long period ofstruggle of the Albanians headed by George Kastrioti againstthe Ottomans came to an end with the fall of Durresi (1501).The country was almost destroyed and the economical situ-ation was dire. The Ottomans were trying to impose – as inall of their conquests – their rules, and among others a strongcampaign began with the aim of converting the population toIslam. In the framework of this campaign, the construction ofbig Christian religious buildings with visible Christian signswas forbidden. Although the campaign was successful up toa certain degree in the cities, most of the population, espe-cially those people living in the countryside, opposed stronglythis campaign by preserving their Christian religion. Due tothis situation, Onoufrios worked in simple, small churcheswith no architectural value, situated in small and remote vil-lages. Most of them were rebuilt on the foundations of olderruined churches. All of them are single-aisle basilicas withno dome, no belfry and very few differences from each other.From the outside they resemble normal houses.

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Onoufrios probably began his activity as an icon painterin the city of Berat, and he later extended his activity, cover-ing the decoration of whole churches with wall-paintings andicons. All of the icons attributed to him are not signed. Theattribution is based on stylistic similarities between the iconsand the wall-paintings with inscriptions.

Inscriptions of Onoufrios have been found in fourchurches: “St. Nikolaos” in Shelcan, Albania, “St. Apos-tles” (1547) and “St.Anargyroi” in Kastoria, Greece – wherethe wall-paintings were not saved – and “St. Paraskevi”(1554) in Valsh, Albania. Others are attributed to him thechurch of “St. Theodori” in Berat, Albania (before 1547), thechurches of Transfiguration and “St. Nicolas” in Zrze, Prilep,FYROM (probably 1535) and perhaps the church of Mol-davita monastery in Moldavia, Romania (probably in 1537).

All the authors that have studied his works agree on thefact that he is one of the best icon painters of the whole Balkanregion and the best painter that had ever worked in Albanianterritory. His individual character can be distinguished in thework of his students: his son Nikola (who inherited his stylein painting), Onoufrios from Cyprus, David Selenicasi, andother painters.

2 Experimental

The monuments. For the present study, samples were col-lected from three of the above mentioned churches: “SaintTheodori”, “Saint Nikolaos” and “St. Paraskevi”.

“St.Theodori” (Fig. 1a) is situated beside the main gate ofthe Berat castle. This single-aisle basilica (9×3.6 m) with un-decorated stonewalls and low-tiled timber roof was built on

FIGURE 1 Saint Theodori (a),Saint Nikolaos (b), Saint Paraske-vi (c) and the inscription of SaintNikolaos (d)

the foundations of an older church during the first half of the16th century. The interior of the church is lit by two windows,one situated on the roof and the other on the vaulted wall of thesanctuary. There is no iconostasis in the church. The existingfragments of wall paintings indicate that the entire church hadbeen decorated. The hands of two different iconographers canbe distinguished from the artistic level of the fragments. Thefragments of wall paintings on the eastern walls of the churchwere painted by Onoufrios, while the artist of those on thenorthern and southern walls is anonymous. These latest frag-ments are not of the same artistic level as those of Onoufrios.The work of Onoufrios on the eastern wall is seriously dam-aged, mainly in the upper part. On the conch of the sanctuary,the right hand of the central figure of Saint Mary Platytera stillexists and the full height figures of Saint Basil the Great andSaint John Chrysostom. Above, the scene of the Annunciationis depicted on both sides of the wall.

The church of “St. Nikolaos” (Fig. 1b) in Shelcan isa single-aisle basilica with narthex and side porch. It hasa wall iconostasis with two doors. It is thought that the churchwas ruined and was rebuilt between 1547 and 1554 whenOnoufrios worked for its decoration. The whole church is dec-orated with wall paintings. Of the several inscriptions, twoof them are related with the names of the authors of the wallpaintings. The first inscription, as always in Greek, situated onthe wall on the left side of the apse, mentions Onoufrios as thepainter (Fig. 1d):

“When you raise your hands towards God, you Ministerof God, mention also me the sinner and ignorant painterOnoufrios”,

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PAVLIDOU et al. Onoufrios, the famous XVI’s century iconographer, creator of the “Berati School” 711

while the second situated on the western wall above theentrance explains that this part of the church was painted byan anonymous painter in 1625. So the eastern walls (apse),iconostasis and a small part of the northern and southernwalls close to the iconostasis were painted by Onoufrios,while the other wall paintings were painted by an anony-mous painter, who was less skilful than Onoufrios. Evenin the area of the apse one observes the hands of a third,less skilful painter in some places. It seems that Onoufriospainted the scenes in the upper part of the walls and let hisassistant finish some of the figures in the lower part of thewalls.

The church of “St. Paraskevi” (Fig. 1c) in the village ofValsh is a small single-aisle basilica with a wall iconostasisand a small porch supported by two columns on the west-ern side. The church was built in 1554, a time in which, as isdocumented by the inscriptions, the whole church was dec-orated with wall paintings by Onoufrios. The interior of thechurch is still decorated with wall paintings some of which aredamaged. There are also signs of wall paintings on the outerwestern wall.

2.1 Sampling

A total of 24 kinds of samples that include plas-ters and pigments of different colours were collected from thethree churches. In each of the sampling points, small piecesof pigment and plaster (about 5 mm2) were removed witha scalpel and placed in small plastic vials with hinged capsto avoid contamination, these being the samples for FTIR,SEM-EDS and optical microscopy, while a small amount ofmaterial was also rubbed off the same spot of painted area bymeans of a dry cotton bud (a Q-tip) that was next placed ina clean plastic bag, these being the samples for the TXRF. Dueto the destructive nature of sampling, the samples were care-

a/a Code number Colour Church

1 T9-G Green Saint Theodori2 T10-R Red Saint Theodori3 T11-B Black Saint Theodori4 T12-Bl Blue Saint Theodori5 T13-Y Yellow Saint Theodori6 T14-Br Yellow Saint Theodori7 T15-R Red Saint Theodori8 T16-W White Saint Theodori9 T17-R Brown Saint Theodori10 T18-Pl Plaster Saint Theodori11 N9-Pl Plaster Saint Nikolaos12 N10-B Black Saint Nikolaos13 N11-R Red Saint Nikolaos14 N12-Y Yellow Saint Nikolaos15 N13-W White Saint Nikolaos16 P1-Pl Plaster Saint Paraskevi17 P2-R Red Saint Paraskevi18 P3-B Black Saint Paraskevi19 P4-Y Yellow Saint Paraskevi20 P5-W White Saint Paraskevi21 P6-Br Brown Saint Paraskevi22 P7-G Green Saint Paraskevi23 P8-Gr Grey Saint Paraskevi24 P9-Gr Grey Saint Paraskevi

TABLE 1 Description of the samples

fully chosen from areas that had no aesthetic or iconographicvalue for future reconstruction.

Table 1 reports the sampling performed on the varioussites. In Fig. 2a–c is presented the exact provenance of eachsample.

A common characteristic of the wall paintings in thestudied churches is related with their state of the preservation.Apart from the damages, the remaining fragments of the wallpaintings seem to suffer – more or less – from a colour change.Looking carefully, one can can observe topically white areasas a thin layer. This phenomenon, related probably with theenvironmental pollution, is observed also in other churchesand is discussed in the continuation.

2.2 Methodologies

Samples were examined by optical microscopyusing an Olympus BX60M optical microscope equipped withan Olympus DP10 digital camera.

FTIR spectra were obtained using a Perkin-Elmer FTIRspectrometer, model Spectrum1000 connected with a Perkin-Elmer FTIR microscope model i-series, equipped with a nitro-gen-cooled MCT detector. In order to collect the spectra ofeach colour layer, a small amount of each layer was removedby micro-scalpel and placed on the surface of a freshly pre-pared KBr pellet. The IR spectra, in transmittance mode, wereobtained from different areas of the specimens, using an aper-ture of 20–100 µm, in the spectral region 550 to 4000 cm−1.The resolution was 4 cm−1 and the number of co-added scanswas 64 for each spectrum. The spectrum of the KBr pellet wasused as background. The presented spectra are baseline cor-rected. A database of FTIR spectra of reference inorganic andorganic materials was used to characterize the unknown mate-rials (pigments) of the samples.

The same pellets, analyzed by FTIR, after being coatedwith carbon, were analyzed by SEM-EDS. Scanning elec-tron microscopy (SEM) was carried out using a JEOL JMS-840A scanning microscope equipped with an energy disper-sive X-ray (EDS) Oxford ISIS 300 micro-analytical system.Operating conditions were: accelerating voltage 20 kV, probecurrent 45 nA and counting time 60 s, with ZAF correctionbeing provided on-line.

The TXRF analysis system is composed of a total re-flection module (Vienna Atominstitute) attached to a tubeexcitation system (Philips PW 1729 X-ray generator andPW 2215/20 Mo anode X-ray tube), an X-ray spectrometer(Si(Li) detector) and spectrum acquisition system (CanberraMod 2024 fast spectroscopy amplifier, Mod 8076 ADC, Mod3105 high voltage power supply and Genie 2000 MCA.

3 Results and discussion3.1 Plaster

In the FTIR spectra of all plasters, a common char-acteristic is the strong presence of calcium carbonate witha small participation of gypsum and silicon compounds. Theexistence of calcite is identified from the bands at 1445, 866and 712 cm−1 (due to the CO2−

3 group of calcite), while thebands at 602, 668, 1146, 3406 and 3550 cm−1 are attributedto the bending and stretching modes of the SO4 group of gyp-sum. When silicates or alumino-silicates materials are added

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FIGURE 2 Saint Theodori (a), Saint Nikolaos (b) and Saint Paraskevi (c)

to the plaster, the FTIR spectrum (Fig. 3) reveals the mostcharacteristic bands of the SiO4 tetrahedra at the spectral re-gions 1200–900 cm−1 and 500–400 cm−1 [3, 4].

The SEM-EDS analysis of plaster samples from allchurches show that calcium is the element with the highestconcentration associated with smaller amounts of magne-sium, silicon and partially sulphur – attributed to gypsum(Table 2) [5, 6]. Therefore the FTIR and EDS results are ingood agreement. Similar results were obtained from TXRFmeasurements of the plaster samples.

The small participation of gypsum was not always de-tected to the FTIR spectra, obtained from different areas of thespecimens, this fact leading to the belief that a small amountof gypsum – after its grinding – was probably mixed withlime (CaO) and aggregates rather than being applied above thesmoothest plaster (the intonnaco) as a separate layer. Similarresults were obtained from the SEM-EDS analysis of plas-ter samples, as grains of gypsum were found scattered in the

layers of plaster, without showing any larger topical concen-tration beneath the pictorial layer. Careful observing at 2300×magnitude showed a differentiation in the size between thegrains with gypsum and grains of calcite, as the grains withgypsum range between 8–10 µm while the calcite ones aremuch smaller, about 2–3 µm in diameter (Fig. 4).

3.2 Deterioration

As mentioned above, the surface of the wall paint-ings was covered topically – more or less – by white areashaving a crystalline texture (Fig. 5). With the FTIR analy-sis of these affected surfaces, for Saint Theodori and SaintParaskevi churches, gypsum and calcium oxalate are identi-fied, while for Saint Nikolaos only gypsum.

In literature there are mentioned two main processes thatlead to the deterioration of the wall paintings [7, 8]. The firstone is related with the formation of gypsum during sulphation,

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FIGURE 3 Representative FTIR transmittance spectra from studied plas-ters (o for gypsum and * for calcite)

Sample % Ca % S % Al % Si % Mg

T18-Pl 32–62 0.5–9.2 0–1 0.5–5.3 0.3–1.6N9-Pl 28.9–34 1.1–8.3 1.1–2.6 0.3–1.5 0.8–2.6P1-Pl 20–31 0.7–8.3 0.4–2.9 0.5–3.8 0.7–0.9

TABLE 2 EDS results from the plasters

which involves the dry deposition reaction between limestone(CaCO3) and sulphur dioxide (SO2) gas, in the presence ofhigh relative humidity, an oxidant and a catalyst (Fe2O3 orNO2). In that case gypsum is primarily detected on the sur-face. The second one is related with the presence of lichens,which by the excretion of oxalic acid convert calcite to cal-cium oxalate.

In the Fig. 6, typical FTIR spectra from these affectedsurfaces are presented. Beyond the identification of cal-cite and the pigment that is used, the presence of gypsumcould be identified from the characteristic peaks of gypsum(CaSO4 ·2H2O) at 602, 668, 1146, 3406 and 3550 cm−1,while the presence of calcium oxalate (CaC2O4 ·H2O) is evi-dent mainly from the band at 1320 cm−1. Based on the FTIRresults, it can be considered that an important deterioratingfactor of the churches is the salt efflorescence, gypsum andcalcium oxalate [9, 10].

The identification, by FTIR and EDS methods, of gypsumand calcium oxalate in the pigments analysis is attributed todeterioration and will not be discussed in the continuation.

FIGURE 4 Backscattered electronmicrograph (a) and dot mapping (b)of the sample P1-Pl

FIGURE 5 Sample P2-R of red colour, affected by deterioration

FIGURE 6 Typical FTIR spectra from affected surfaces of yellow samples(o for gypsum, + for calcium oxalate and * for calcite)

3.3 Colours

Fresco is an ancient technique of painting on walls.Originally, the colour was applied to damp plaster. The ma-terial used to paint frescos does not conform to our usualdefinition of a paint, which requires the presence of a binder.As the plaster dries, the particles of pigment are pulled intothe surface of the plaster and locked in place by particlesof Ca(OH)2 which react with CO2 and convert to CaCO3 ata very small rate as the plaster dries. The plaster acts as binder,ground and support and in the end, when the pigment becomesan integral part of the plaster, the plaster acts as the “paint”

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as well. Fresco is the one painting medium in which all of thecomponent parts merge to form a single unit [11]. The strongpresence of calcium carbonate in samples combined with theinexistence of any organic compound in all collected paintedsamples proves the use of the technique of fresco for the con-struction of the studied wall-paintings.Blue pigments. The presence of copper in great amounts fromthe TXRF (Fig. 7b) and EDS results (Table 3) of the blue spe-cimen (Fig. 7a) gives us a strong indication that the pigmentis azurite. The comparison of the obtained FTIR spectrum(Fig. 7c) of the sample, with the spectrum of azurite from thespectral library, confirms that the used blue pigment is azurite.

Green pigments. Green Earth could be recognized from thecomparison of the results of EDS and FTIR methods. The

Colour Blue Green Red Yellow Brown Black White GreyT12-Bl P7-G N11-R N15-R P4-Y P6-Br N10-B T16-W P8-Gr

% Ca 0.8–46.4 24.8–35.3 5.0–79.7 1.9–12.1 4.3–21.2 16.4–46.5 4.0–44.4 9.7–53.6 57–59% Cu 43.6–63.9 – – – – – – – –% Hg – – – 40.2–86.2 – – – – –% Fe 0–2.8 2.0–19.4 2.7–17.8 – 5.1–19.2 2.4–18.3 – – –% Al 1.4–3.3 2.5–10.4 1.9–6.2 0–1 3.9–7.9 6–7 0.1–5.5 1.3–4.4 1–2% Si 0.5–5.3 3.7–17.9 5.2–17.5 0–1 7.4–15.2 4.9–14.1 1–32.6 0.6–5.8 0.9–2.6% Mg 0.5–1.5 1.6–9.8 4.8–14.0 – 1.8–4.1 2.0–14.9 0.7–12.4 2–3 0.6–1.4% S 0–13.1 0–12.4 0–3.2 5–10 0–5.8 3.1–8.9 0.2–23.9 0–12.8 37–40

TABLE 3 EDS analysis from pigments

FIGURE 7 Optical photograph ofblue colour (sample T12-Bl) (a),TXRF of T12-Bl (b) and FTIR trans-mittance spectra from blue pigment(o for gypsum, + for calcium oxalateand * for calcite) (c)

presence of Fe, Si and Mg from EDS analysis (Table 3) ofgreen samples, leads to the conclusion that the pigment can beattributed to Green Earth. Siliceous minerals of greyish greencolour known generally as Green Earth are found widelythroughout the world and have long appealed to the artists.There is a number of closely related green earth mineralssuch as celadonite, glauconite etc. Because of the similaritiesin these clay minerals, precise identification is difficult [12].From a detailed examination of FTIR spectra (Fig. 8), the fournarrow bands OH stretching in the 3610–3530 cm−1 regionand the area 1100–900 cm−1 of Si−O stretching lead us tocharacterize the green earth as celadonite.

Red pigments. Elemental analysis on the red coloured layers(Fig. 9a) from St. Nikolaos and St. Paraskevi churches

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PAVLIDOU et al. Onoufrios, the famous XVI’s century iconographer, creator of the “Berati School” 715

FIGURE 8 Representative FTIR transmittance spectra from green pigment(o for gypsum, + for calcium oxalate and * for calcite)

(Table 3, sample N11-R) identified Fe along with Al and Si,indicating the existence of iron oxide as the possible mate-rial producing the red colour. Moreover the coexistence of thealumino-silicate materials guide to the consideration that thepigment is red ochre. This result is supported with the FTIRspectra of the above samples that are almost identical with thespectrum of the red ochre from the spectral library (Fig. 9b).

FIGURE 9 Optical photograph ofred pigment (sample P2-R) (a), Rep-resentative FTIR transmittance spec-tra from red pigment (o for gypsum,+ for calcium oxalate and * for cal-cite) (b) and TXRF of T15-R (c)

The red samples from St. Theodori church present a dif-ference referring to the use not only red ochre but alsocinnabar, especially for the light red areas. The identificationof cinnabar is based on the presence of Hg and S as majorelements in the EDS results (Table 3, sample T15-R). Hg wasalso detected by TXRF (Fig. 9c). The FTIR spectra do not giveany information about the cinnabar as the characteristic peaksof HgS appear in FIR region at about 345 and 285 cm−1, andit is impossible to reveal with the MCT detector of the FTIRmicroscope, where the lower wavenumber is ∼ 550 cm−1.

Yellow pigments. Yellow ochre is a natural earth pigment,which consists of silica and clay – most likely in aluminosil-icate form as kaolinite – and owes its colour to various hy-drated forms of iron oxide ,in particular the mineral goethite,FeOOH. Yellow ochre has been universally used as a pigmentfrom the earliest history [13] and is one of the basic yellowpigments in Byzantine iconography.

The main elements that are present in EDS results(Table 3) of all yellow samples – beyond Ca – are Fe, Si, Al.Moreover the similarities of the FTIR spectra of the yellowsamples (Fig. 10) with the spectrum of the yellow ochre of thedata base (peaks of kaolinite at 3697, 3669, 3652, 3620 cm−1)lead to be characterized the yellow pigment as yellow ochre.

Brown pigments. The EDS analysis of the samples (Table 3)confirms the presence of Fe, Al, Si in great amounts that

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indicate the iron oxides as the main component of the pig-ment [14]. In Byzantine painting the brown pigment tradition-ally used was raw or burnt umber, which is a ferric inorganicmaterial naturally containing large amounts of aluminium sil-icate compounds. Its brown hue comes from the MnO2 con-tained (6–15% by weight), which is black in colour [13]. Sinceno Mn was detected in the layer examined, the presence ofumber was excluded. The characteristic bands of aluminiumsilicate compounds at 1030 cm−1 and the double at 790 and779 cm−1 that can be observed in the FTIR spectrum (Fig. 11)of this layer, confirmed the use of ochres possibly mixed withcarbon black [15].

Black pigments. For the black coloured samples the EDS andFTIR methods did not succeed in giving any information. Themost common black pigments in that period time were carbonblack and bone black. The absence of P from the EDS results(Table 3) along with the absence of PO4 group in FTIR spectraguide us to estimate that the used black pigment was carbonblack (amorphous carbon).

FIGURE 10 Representative FTIR transmittance spectra from yellow pig-ment (o for gypsum, + for calcium oxalate and * for calcite)

FIGURE 11 Representative FTIR transmittance spectra from brown pigment(o for gypsum, + for calcium oxalate and * for calcite)

White pigments. From the presented EDS results (Table 3),the white samples show Ca in great quantities while in theFTIR spectra the characteristics peaks of calcite are identified(Fig. 12). These results indicate that CaCO3 was used mainlyas white pigment.

Grey pigments. The findings from the EDS (Table 3) andFTIR analyses combined with the results for white and blackpigments, lead to the consideration of grey pigment as a mix-ture of CaCO3 and carbon black.

Summarizing the above results, we present the used pig-ments from the painter Onoufrios in Table 4.

4 Conclusions

Concluding from the technical point of view, itcan be said that the chosen analytical methods permitted theidentification of plasters and pigments of the three monu-ments. The plaster of all the wall paintings, made with thefresco technique, was generally characterized by the strongpresence of calcite with a small participation of gypsumand silicon compounds. Plaster samples from the churchesof “St. Theodori” and “St. Nikolaos”, taken from the wall-paintings of anonymous painters, as mentioned in the intro-duction, showed more or less no participation of gypsum,

FIGURE 12 Representative FTIR transmittance spectra from white pigment(o for gypsum, + for calcium oxalate and * for calcite)

Saint Theodori Saint Nikolaos Saint Paraskevi

Green Green earth – Green earthBlue Azurite – –Yellow Yellow ochre Yellow ochre Yellow ochreRed Red ochre Red ochre Red ochre

+/or Cinnabar

Brown Red ochre – Red ochreWhite Calcite Calcite CalciteBlack Carbon black Carbon black Carbon blackGrey – – Calcite

+ Carbon black

TABLE 4 The pigments used in the three studied churches

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PAVLIDOU et al. Onoufrios, the famous XVI’s century iconographer, creator of the “Berati School” 717

thus leading to the conclusion that gypsum is a character-istic of Onoufrios’ wall painting technique. FTIR and EDSanalyses showed that a small amount of gypsum was prob-ably mixed with lime (CaO) and aggregates rather thanbeing applied above the smoothest plaster as a separatelayer.

Having studied enough representative wall painting worksof the iconographer Onoufrios, we can characterize his tech-nique and the materials used.

For the wall paintings, he used the fresco technique, andthe inclusion of gypsum in the plaster is a characteristic of hisway of painting.

As is testified from the Table 4, Onoufrios used the sametype of pigments for the same colour shades in all threechurches (azurite, green earth, red ochre, cinnabar, yellowochre, carbon black, calcite) with the exception of cinnabar,for the rendering of red colour, detected only at the church of“St. Theodori”.

Regarding the present state of the wall paintings in thestudied monuments we commented that the painted samplessuffered from deterioration, identified even visually. Furtheranalysis of the effected areas identified the presence of gyp-sum in all churches and oxalate, except “St. Nikolaos”. Theseresults indicate the presence of two types of deterioration:(i) The alteration of calcite (CaCO3) – which is in high amountin wall paintings – to gypsum (CaSO4 ·2H2O) due probablyto acid air pollution (sulphur oxides), (ii) Biodeterioration bylichens which cause – except of mechanical damages – andchemical damages by excretion of oxalic acid.

ACKNOWLEDGEMENTS This work was supported by theHellenic General Secretariat of Research and Technology, Ministry of Devel-opment under the Joint Greek – Albanian Research and Technology Program

entitled “Identification of late-Byzantine and post-Byzantine wall paintings’materials and technology in Albania: the mutual influence between Albanianand Greek iconographers”.

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