Analysis of the Materials and Painting Techniques Used in Medieval Mural Paintings in Slovenia up to 1380

9789610 508847 ISBN 978-961-05-0884-7 HTTP://ZALOZBA.ZRC-SAZU.SI 49 € Mija Oter Gorenčič: Medieval Murals. New Perspectives and Research Approaches. Preface Sara Salvadori: Reconsidering the Frescoes in the Church in Vieux Pouzauges (Bas-Poitou, France) Mateja Neža Sitar, Ajda Mladenović, Vlasta Čobal Sedmak, Martina Lesar Kikelj, Simona Menoni Muršič, Anita Klančar Kavčič: Overlooked Aspects of Wall Painting Evaluation and Treatment Anita Klančar Kavčič: The Wall Paintings in the Church of St Cantianus in Vrzdenec, Slovenia. Past Conservation-Restoration Interventions, Conservation Challenges, Interpretation and Evaluation Sara Turk Marolt: Mural Paintings from the 14th Century in the Church of Saint Maurus in Arcano Superiore (Friuli, Italy) Anabelle Križnar, Katja Kavkler, Sabina Dolenec: Analysis of the Materials and Painting Techniques Used in Medieval Mural Paintings in Slovenia up to 1380 Susanne Kaun, Elisabeth Andersen: Medieval Murals in Norwegian Stone Churches Gorazd Bence: The Hunt for the Miraculous Stag or St Giles’s Hind? On the Iconography of the Mural Painting in the Nave of the Old Parish Church in Turnišče, Slovenia Patrícia Monteiro: Portuguese Medieval Wall Paintings. Missing Pieces for a Long-Awaited Artistic Inventory Mija Oter Gorenčič: New Discoveries About the Murals in the Chapel of Turjak Castle, Slovenia Anna Kónya: Images, Liturgy and Illusionism. Late Gothic Wall Paintings Imitating Winged Altarpieces Katarina Richter: The Two Mediaeval Churches of Camporosso in Valcanale, Italy Katarina Mohar: Slovenian Frescoes at Yugoslav Medieval Art Exhibitions during the 1950s Opera Instituti Artis Historiae Medieval Murals New Perspectives and Research Approaches Edited by Mija Oter Gorenčič Expert and language editing: Blaž Resman English proofreading: Oliver Currie, Monika Fritz Slovene proofreading: Mija Oter Gorenčič Each contribution in the book was peer-reviewed by two of the following experts: Marjeta Ciglenečki, Monica Galeotti, Janez Höfler, Zsombor Jékely, Manfred Koller, Polona Vidmar. Design, layout and photo editing: Andrej Furlan Issued by ZRC SAZU, France Stele Institute of Art History Represented by Mija Oter Gorenčič Publisher: Založba ZRC Represented by Oto Luthar Založba ZRC general manager and editor-in-chief: Aleš Pogačnik Print: Present d. o. o., Ljubljana 400 copies First edition, first print run / First e-edition Ljubljana 2024 The book is aresult of the research programme Art in Slovenia at a Cultural Crossroads (P6-0061) and research project Transformations – From Material to Virtual. Digital Corpus of Mural Painting – New Dimensions of Medieval Art Research in Slovenia (J6-2587) funded by the Slovenian Research and Innovation Agency. The Open Access version has been made available under a Creative Commons Attribution-ShareAlike 4.0 International license (CC BY-SA), except for the material where there is indicated otherwise in the credit line. https://doi.org/10.3986/9789610508847 Kataložna zapisa o publikaciji (CIP) pripravili v Narodni in univerzitetni knjižnici v Ljubljani ISBN 978-961-05-0883-0 COBISS.SI-ID 204012803 ISBN 978-961-05-0884-7 (PDF) COBISS.SI-ID 203996163 Cover photo: Procession of the Magi, detail, church of St Cantianus in Vrzdenec, Slovenia (© ZRC SAZU, UIFS, photo: Andrej Furlan) Medieval Murals New Perspectives and Research Approaches Edited by Mija Oter Gorenčič Ljubljana 2024 123 Medieval Murals. New Perspectives and Research Approaches Analysis of the Materials and Painting Techniques Used in Medieval Mural Paintings in Slovenia up to 1380 Anabelle Križnar University of Ljubljana, Faculty of Arts, Department of Art History, Ljubljana, Slovenia, and University of Seville, Faculty of Fine Arts, Department of Sculpture and Art History, Seville, Spain, [email protected] Katja Kavkler Institute for the Protection of Cultural Heritage of Slovenia, Restoration Centre, Ljubljana, Slovenia, katja.kavk[email protected] Sabina Dolenec Slovenian National Building and Civil Engineering Institute, Ljubljana, Slovenia, sab[email protected] Introduction Scientific analytical methods are becoming increasingly more important for a truly comprehensive understanding and better-grounded interpretation of visual works of art. Until recently, the study of artworks had been narrowly focusing on stylistic classification, on resolving open questions of iconography and on establishing stylistic links between particular mural cycles using the traditional means of stylistic analysis, since these are the principal tasks of art history. But not all information can be gathered by this approach only, considering that artists also expressed themselves through their selection of materials and the mastering of painting techniques, which in turn affects the modelling (which is softer or rougher as a result), as well as the subsequent conservation of the artwork in later centuries. Therefore, art historians need to collaborate with natural scientists, principally chemists, physicists, geologists, biologists as well as with conservators and restorers in order to fully understand a given monument not only in terms of its artistic form but also in terms of its material structure and execution technique. Such an interdisciplinary approach can inform intervention procedures and enable a perdurable conservation of monuments. https://doi.org/10.3986/9789610508847_005 124 Anabelle Križnar, Katja Kavkler, Sabina Dolenec The present project focuses on mediaeval mural paintings in Slovenia to 1380. Over 60 mural cycles have been systematically studied including from a material and technical perspective and in close collaboration with art historians and restorers. The murals included in this study can be found throughout the territory of present-day Slovenia. During the late Middle Ages, this geographical area was – along with the neighbouring territories – criss-crossed by busy supraregional trade routes and became as a result a paradigm example for studying cultural exchange between the continental European North and the Mediterranean South. This exchange is also reflected in painting style and in painting techniques. Most of the murals have been previously studied by Slovene and foreign art historians,1 but there are several new discoveries that have not been investigated yet. All mural paintings up to 1380 (old and new discoveries alike) have been now reevaluated and had material analysis carried out on them. Before this, only a few material studies had been made in Slovenia to date,2 which makes this research even more pertinent. Objectives The present research project, which is still ongoing, has two primary objectives. First, it aims to significantly supplement the results of earlier art-historical research and, secondly and more importantly, it seeks to identify by scientific methods the painting materials and techniques used by individual late mediaeval mural painters and their workshops. The material analyses focus primarily on: (a) the characterization of supports (plasters), including their composition (binders and aggregates), impurity, consistency, varieties of sand (colour, granulation), the number of layers and the application of giornatas; (b) the use of lime-wash; (c) the identification of selected pigments and their possible degradation; (d) the identification of binders; (e) the sequence of colour layers; (f) the colour modelling; (g) the painting process from the preparatory work (under-drawings, incisions, pouncing, under-paintings) to the final colour modelling (shades, highlights); and the painting technique (a fresco, a secco, lime technique or combined). A comparison of obtained results enable us to recognize an artistic process or technique, a characteristic brushstroke, helping to identify an artist or a link to a workshop, and thus supporting or rejecting specific art-historical hypotheses. 1 STELE 1935; STELE 1969; RADOCSAY 1977; PROKOPP 1983; HÖFLER 1985; ŽELEZNIK 1993; HÖFLER 1996; ZIMMERMANN 1996; HÖFLER 1997; VODNIK 1998; HÖFLER 2001; HÖFLER 2004; BALAŽIC 2008. 2 POHL 1966; PIRNAT 1972; MOLE 1984–1987; BOGOVČIČ 1995; NEMEC 1995; KRIŽNAR 2006. 125 Analysis of the Materials and Painting Techniques Used in Medieval Mural Paintings in Slovenia up to 1380 Analytical Methods and Techniques After a precise visual examination of the paintings in situ, non-invasive techniques are applied where possible, such as digital microscopy (DM), ultraviolet fluorescence (UVF), VIS spectrophotometry and portable X-ray fluorescence (XRF). However, in many cases the paintings are too high and thus inaccessible with the equipment, and the interior of the churches is generally too bright for UVF. Therefore, small samples of ca. 2–4 mm3 must be extracted from several areas of interest (as few as possible), including support, pigments or colour layers. Different laboratory techniques can be used, among which the most common ones are optical microscopy (OM), scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDX), stationary X-Ray Fluorescence Spectroscopy (XRF), X-ray powder diffraction (XRD), Fourier Transform Infrared spectroscopy (FTIR) and Raman Spectroscopy. Samples are therefore prepared according to the analytical procedure implemented; raw samples can be studied by OM, SEM-EDX, XRF or Raman, but they are mostly embedded in resin to elaborate cross-sections (analysed by OM, SEMEDX or Raman) or prepared as KBr pellets (FTIR), while plasters are crushed into powder (XRD). UVF reveals later interventions, based on the characteristic fluorescence of specific materials under UV light that can distinguish between older and newer materials.3 VIS spectrophotometry, applied in reflectance mode for the study of mural painting, helps us to identify and classify colours using surface measurements that can quantify visible effects depending on the colouring materials used, i.e. pigments.4 XRF offers an elemental analysis of the irradiated point, characterizing the chemical elements and in turn the materials applied (pigments, support). The results are, however, limited, since it detects only elements with a higher atomic number such as those above 14 (Z>14), which means that only inorganic materials can be identified using this method. Further, different materials characterised by the same chemical element such as copper greens or lead pigments, cannot be distinguished.5 OM is the basic technique for the analysis of paint layers. Through different magnification under reflected light it enables us to recognise the composition of the support (plaster), the sequence of colour layers and thus the painting procedure, and also to identify certain pigments according to their characteristic granulometry as well as possible pigment changes; it can even discern the painting techniques used.6 SEM offers much higher magnification of the sample studied compared to OM, and is generally used in combination with EDX for elemental analysis. Black-and-white SEM images enable us to visualize the morphology 3 DE LA RIE 1982; MATTEINI, MOLES 1984, pp. 171–177; ALDROVANDI, PICCOLO 2003, pp. 67–84; STUART 2007; CONSENTINO 2015. 4 BACCI 1995; OLTROGGE 2008; ARTIOLI 2010, pp. 46–47; Spectroscopy 2021, pp. 103–131. 5 MATTEINI, MOLES 1984, pp. 133–139; APPOLONIA, VOLPIN 1999, pp. 30–33; SECCARONI, MOIOLI 2004; ARTIOLI 2010, pp. 34–37; Analytical Chemistry 2017, pp. 77–128. 6 MATTEINI, MOLES 1984, pp. 37–55; APPOLONIA, VOLPIN 1999, pp. 20–27; ARTIOLI 2010, pp. 64–66. 126 Anabelle Križnar, Katja Kavkler, Sabina Dolenec of the sample and distinguish between light and heavy elements present in the material. The high magnification helps at selecting specific areas or individual particles for chemical analysis, offering very precise results.7 The XRD technique is generally used for plaster characterization in the study of mural paintings. It identifies compounds (minerals, phases) and can give us a good insight into a plaster composition (binder, aggregate types) and weathering products.8 FTIR and Raman are two of the most frequently used molecular techniques in art that are also suitable for the identification of organic materials such as colorants or binders. Both methods use different physical processes such as absorption, emission and vibration for identification of molecular structure of the analysed material.9 Recently, the emphasis has been on non-invasive techniques which do not require sample extraction. Therefore, most of the equipment required for the above techniques, including XRF, XRD, FTIR and Raman among others, have been developed as mobile units in order to be to use them in situ.10 Nevertheless, high quality results, especially for FTIR and Raman, are difficult to obtain outside the laboratory due to various non-controllable factors. No portable equipment was available for this research. For extracted samples prepared according to the analytical technique, OM, XRD and Raman were primarily used. FTIR and SEM-EDX were applied only on certain selected samples. Other techniques will be added if necessary. The optical microscopy of cross-sections was performed in visible (VIS) and ultraviolet (UV) light to obtain information on the stratigraphy of the selected samples. Cross-sections were examined with an Olympus BX-60 microscope and SC50 (Olympus) digital camera in reflected light at 50x to 200x magnification. XRD was selected for plaster characterization. Cross-sections and raw samples were analysed using a Raman spectrometer LabRAM HR800 (Horiba Jobin-Yvon) connected to an Olympus BXFM microscope, with a 785 nm wavelength laser and CCD detector in the range between 80 cm-1and 1800 cm-1at a spectral resolution of 1 cm-1. Calibration was performed using Si crystal. The time and filter were adapted to each sample. The phase composition of the raw plaster samples was determined using a PANalytical Empyrean X-ray diffractometer (Malvern Panalytical, Malvern, UK) equipped with CuKaradiation and a PIXcel 1D detector. The samples were ground to a particle size of less than 63µm. They were put in zero diffraction plate. The samples were measured at 45 kV at a current of 40 mA, in the range of 4 to 70°2q, at a step size of 0.013°2qwith a scan step time of 68s. The analysis of X-ray diffraction patterns was performed with the X’Pert High Score Plus diffraction software v. 4.9 from PANalytical using PAN IICSD v. 3.4 powder diffraction files. Some selected 7 MATTEINI, MOLES 1984, pp. 75–86; APPOLONIA, VOLPIN 1999, pp. 38–41; ARTIOLI 2010, pp. 66–68; Spectroscopy 2021, pp. 71–102. 8 MATTEINI, MOLES 1984, pp. 125–132; APPOLONIA, VOLPIN 1999, pp. 33–38; ARTIOLI 2010, pp. 50–52; Analytical Chemistry 2017, pp. 77–128; Spectroscopy 2021, pp. 161–207. 9 MATTEINI, MOLES 1984, pp. 107–110; Analytical Chemistry 2017, pp. 129–211; Spectroscopy 2021, pp. 45–69. 10 Analytical Chemistry 2017, pp. 41–75. 127 Analysis of the Materials and Painting Techniques Used in Medieval Mural Paintings in Slovenia up to 1380 raw samples were analysed by FTIR with a Spectrum 100 spectrometer connected to a Spectrum Spotlight 200 (PerkinElmer) microscope. Layers were separated with a scalpel and in some cases solvents of different polarity were used to extract materials form the mixtures. All samples were analysed in transmission mode, compressed in a diamond anvil cell. Spectra were scanned using a MCT detector in the range between 4000 cm-1and 600 cm-1with a spectral resolution of 4 cm-1, averaging 32 scans for each spectrum. For SEM-EDX analysis, the stratigraphic sections had been previously metallized with a thin layer of gold (Au) and then studied with a JEOL JSM 5400 SEM instrument coupled to an Oxford Link EDX analyser with a Si(Li) detector, Be window, at 20 kV. The combination of all these techniques provides more reliable (and fully verifiable) data concerning the composition of plasters, their impurity and consistency, the possible use of limewash, the selection of pigments and binders, as well as offering other important insights into the painting techniques used by a number of late-mediaeval artists – in particular with respect to painting on fresh mortar (a fresco), lime-technique (painting on a fresh layer of lime-white), painting a secco, or (the most common practice) a combination of these. Such scientific results combined with the stylistic characterization of artworks enables a deeper understanding of an artist/workshop and can even establish authorship or workshop connections between mural cycles. This project represents ongoing research and not all analyses have been carried out yet (such as SEM-EDX), while FTIR has been used only in a few selected samples so far. Painting Materials and Techniques 1. Plaster Plaster is generally made as a mixture of lime as a binder and of sand as aggregate. Images made by optical microscope (OM) reveal different aggregate granulation and colour, which varies from light, almost transparent, to intense red and almost black, indicating different mineralogicalpetrographic and chemical compositions (Fig. 1). Mostly, the aggregate grains have an angular form, however in some cases they can be rounded. They can also vary in their sphericity, for instance being elongated or isometric. Rounded grains can indicate a river or lake provenance of the aggregate, since the water smooths the angular forms. For a good painting surface, the sand must be thoroughly cleaned; if it is not, its impurities can cause damage over time, affecting also the painting surface. As for the binder, a slaked lime (Ca(OH)2) is used, which should be properly cleaned and rested before its use, if not, white lime lumps can form, which can be observed under an optical microscope. Depending on the sand and binder type or possible mineral additives, the plaster can have whiter or darker tonality. Mineralogical composition was determined mainly using an XRD that identified the principal materials in a plasters, such as calcite, dolomite and quartz, while in some plasters also feldspars, illite/muscovite or plagioclases were detected. Their 128 Anabelle Križnar, Katja Kavkler, Sabina Dolenec 2. XRD patterns reveal different plaster compositions, as observed on two samples: (a) plaster made of lime and sand with mineral additives, the church of Our Lady on the Rock in Vuzenica; (b) plaster made of lime and crushed calcite, St Nicholas’s church in Žužemberk (© Slovenian National Building and Civil Engineering Institute, Ljubljana, Materials Department, Laboratory for cements, mortars and ceramics). 1. Microphotographs of plaster samples and colour layers using optical microscopy in reflected light from the following locations: (a) St Peter’s church in Ribičje, (b) St Thomas’s church in Štomaž pod Štjakom, (c) St James’s church above Potoče, and (d) the church of Our Lady on the Rock in Vuzenica. All plasters consist of lime and sand. The samples (c) and (d) reveal a thin layer of limewash under the colour layer (© Institute for the Protection of Cultural Heritage of Slovenia, Restoration Centre, Ljubljana (IPCHS, RC), Scientific department). 135 Analysis of the Materials and Painting Techniques Used in Medieval Mural Paintings in Slovenia up to 1380 Painting Procedures Painting procedures reveal an artist’s way of working and can characterize them, thus helping in the authentication of a painting. These procedures include preparatory drawings, incisions, pouncing, underpaintings, modelling, and final details. Preparatory drawing carried out on the lower plaster layer (arriccio) is known as sinopia, and that on the upper plaster layer (intonaco) as underpainting.22 Sinopia, generally traced in red colour, can be only seen where the upper plaster layer has fallen off, therefore only in rare cases. We must bear in mind, though, that many painters did not use it, especially if they were working only on one layer of plaster; it is a painting procedure more common in Italian art. In our research, we have found sinopia, for example, in the church of St Francis of Assisi in Koper, on the oldest 14th century scene representing the Madonna and child, where the lower part of the mural is damaged. A thin red line is visible, as shown in Fig. 9. An underdrawing can be distinguished more easily, especially where the colour layers have fallen off or where the final contour does not cover it completely. Artists could use different colours: yellow, pink, red, black, though only rarely green.23 On murals up to 1380, yellow, red, and black have been found (Fig. 10). A ruler could have been used to trace auxiliary straight lines (scene bordures, architectural elements), though in most cases 22 Reclams Handbuch 1990, pp. 79–84; KRIŽNAR 2006, pp. 26–27; BROECKE 2015, pp. 97–98, 100–101. 23 Reclams Handbuch 1990, pp. 83–84. 9. A red line of sinopia, drawn on arriccio in a red ellipse. St Francis of Assisi church in Koper (Photo: Anabelle Križnar). 136 Anabelle Križnar, Katja Kavkler, Sabina Dolenec artists chose to use a rope, impregnated in red colour and pressed on the wall.24 A characteristic point-like line marked by the rope can be clearly distinguished in several murals, as we can see on the paintings in the main nave of the church of St James in Ormož (Fig. 10b). Sometimes, the underdrawing can also be discovered by means of cross-sections, revealing a thin colour layer 24 Reclams Handbuch 1990, pp. 76–78. 10. (a) A red underdrawing and (b) straight red lines traced with a wet rope, both from St James’s church in Ormož (the central nave). (c) Yellow underdrawing observed on figures and swords, also revealed on the (d) sample microphotograph (reflected light), St Nicholas’s church in Pangrč Grm (the younger layer) (Photos: Anabelle Križnar). 137 Analysis of the Materials and Painting Techniques Used in Medieval Mural Paintings in Slovenia up to 1380 in yellow (Fig. 10d), red or black under the principal colour layer, especially if the sample was extracted from the area of a contour, where such underdrawing can be expected. Sinopia and underdrawing are generally well preserved since they are done on fresh plaster. Incisions and pouncing are made into a fresh mortar as well, leaving thin or wide, shallow, or deep lines or forms. They are very common in Slovene medieval murals and used principally for saints’ heads and halos (Fig. 11a), but also for other, mostly decorative elements such as crowns, belts, swords, or even entire figures, especially when transferred from a pattern, or for straight lines when rope was not used (Fig. 11b). Underpaintings are uniform colour layers applied under another colour to give it a desired, generally more intense or darker tonality.25 For the most part, expensive pigments such as blue azurite or green malachite were underlaid in order to use less pigment and still obtain a deep colour hue. The underpainting could be grey, known as veneda,26 or dark red, known as morello.27 The first one was generally common in the painting North of the Alps and the second in Italian Trecento 25 Reclams Handbuch 1990, pp. 89–96. 26 The terminology was first employed already by Theophilus in his treatise for a mixture of black pigment and lime, suggesting that a painter underlays malachite or azurite with it (I, 6, 15, 16): THEOPHILUS PRESBYTER 1979, pp. 18, 23, 25. 27 Cennini in his treatise (III, 83) writes about a reddish underlayer, made as a mixture of black pigment with red ochre and suggest using it under blue azurite: BROECKE 2015, pp. 119–121. 11. (a) Deep incisions and pouncings for the halos and head contours, St Trinity church in Knežja Njiva. (b) Straight, thin and shallow incisions, traced with a sharp object and a ruler; many mistakes can be observed, St Ulrich’s church in Tolmin (Photos: Anabelle Križnar). 138 Anabelle Križnar, Katja Kavkler, Sabina Dolenec painting. We find both in Slovene territory, thus confirming the area as a meeting point of northern and southern painting techniques as well as place of collaboration of artists of various provenances. Sometimes, these underpaintings can be discerned even with the naked eye through the upper painting layer, if it is very thin, or on areas where the colour has fallen off. Mostly, though, it can be revealed through cross sections by observing a thicker grey (Fig. 12a) or reddish colour layer between the plaster and the upper colour layer. Veneda and morello used to be applied a fresco, malachite and azurite a secco. Both pigments could have also been applied directly on the plaster (Fig. 5e), which is often the case in pre-1380 murals. Other pigments could have been applied as underpaintings as well, such as yellow earth under green or minium under cinnabar (Fig. 12b), however, it is rarely found. Colour modelling reveals the dexterity of a painter through his brushstroke and colour transitions. The brushstroke can be wide and coarse or thin and precise, resulting in rough or smooth transitions between shades and highlights, creating plane surfaces or round volumes. The oldest paintings are rather flat with predominant line (Fig. 13a), while the more recent ones already show soft modelling and a combination of wide and thin brushes (Fig. 13 b, c). In mural painting up to 1380, the line takes precedence over the colour, observed as strong contours that delimitate an object or figure. We can study in this way the form of the head and hair, eyes, nose, lips, hands and fingers, feet, if the figures are barefoot, and drapery folds. The accuracy of the final contour with the underdrawing, when visible, can also be compared. Such study allows us in many cases to determine if several scenes were carried out by the same painter or not. Such are the cases in Vuzenica and Žužemberk, where the specific form of the faces as well as the very characteristic shading (for example, eyelids in Žužemberk) allow us to attribute it to the same hand or close circle. Therefore, the figures on 12. Sample microphotographs of plasters and colour layers using optical microscopy in reflective light reveal underpaintings: (a) grey under green malachite, cloister, Stična monastery (Votive scene), (b) orange minium under red cinnabar, St George’s church in Ptuj ((a) © IPCHS, RC, Scientific department; (b) photo: Anabelle Križnar). 139 Analysis of the Materials and Painting Techniques Used in Medieval Mural Paintings in Slovenia up to 1380 13. Colour modelling: (a) flat, with a predominant contour, St Oswald’s church in Leskovec nad Višnjo Goro; (b, c) creating volumes with a soft transition between light and dark tones, St Thomas’s church in Štomaž pod Štjakom (© Research Centre of the Slovenian Academy of Sciences and Arts, France Stele Institute of Art History, Ljubljana (ZRC SAZU, UIFS), photos: Andrej Furlan). 14. Colour modelling can contribute to the characterisation and authentication of an artist, comparing the manner of face forms and shading: (a, b) faces of the donor on the chancel triumphal wall and the saint on the triumphal arch, the church of Our Lady on the Rock in Vuzenica. (c, d) Faces of the saint on the Storm scene on the exterior western wall and St Erasmus on the interior nave triumphal wall, St Nicholas’s church in Žužemberk ((a, b) © ZRC SAZU, UIFS, photos: Andrej Furlan; (c, d) photos: Anabelle Križnar). 140 Anabelle Križnar, Katja Kavkler, Sabina Dolenec the upper layer on the triumphal arch and interior presbytery wall in Vuzenica (Fig. 14a, b) must have been painted by the same master or a very close disciple. Similarly, the figure of St Erasmus on the interior wall and the figures in the Storm scene on the western outside wall of Žužemberk church (Fig. 13c, d) are the work of the same workshop, though probably not by the same painter, portraying St Erasmus with a much better and softer modelling and showing his flesh-tone with brighter colour palette. Conclusions This still ongoing research involves the analysis of plasters, pigments, painting techniques and painting procedures of Slovene murals up to 1380. Paintings were first studied in situ, then small samples of support and colour layers were analysed using different analytical techniques (OM, SEM-EDX, XRF, XRD, Raman spectroscopy and FTIR). We still do not have all the results, but those obtained so far enable us to characterize plasters as a mixture of lime and aggregate: the latter is composed mostly of silicates, but in some cases crushed calcite was also used. The pigments are mostly natural inorganic: lime white, yellow, red and green earths, rarely malachite and azurite, while the blacks are organic, mostly carbon or lamp one. In several cases, lead pigments were also applied, but due to their degradation, they have turned black. Black areas can be found also in some areas of azurite or malachite, while we often find degradation from blue azurite to green (para)tacamite. The principal painting technique is a fresco combined with a secco. The proportion of the dry-painted parts varies, depending on the mural cycle and the dexterity of the artist. Lime technique was sometimes applied as auxiliary technique under colour layers. Only in Pangrč Grm was it used as the principal painting technique. The study of painting procedures has revealed sinopia only on one mural, while underdrawings have been easier to discern and were traced with yellow, red or black colour. Incisions and pouncing are very common but can vary in the depth and width of the line/form. For straight lines, mostly a rope soaked in red colour was pressed against the wall. Underpaintings were rarely found under malachite, azurite and, in just one case (Ptuj) they were found under cinnabar. In modelling, the line takes precedence over the colour, therefore we find mostly flat figures and objects. However, in later murals, greater volume and a softer modelling can be appreciated. This is, of course, also dependent on the quality of the artist. The material and technical study of mural paintings can thus make an important contribution to our understanding of an artwork or an artist, as well as informing conservation-restoration work. 141 Analysis of the Materials and Painting Techniques Used in Medieval Mural Paintings in Slovenia up to 1380 Literature ALDROVANDI, PICOLO 2003 Alfredo ALDROVANDI, Marcello PICOLO, Metodi di documentazione e indagini non invasive sui dipinti, Padova 2003. Analytical Chemistry 2017 Analytical Chemistry for Cultural Heritage (ed. Rocco Mazzeo), Berlin 2017. APPOLONIA, VOLPIN 1999 Lorenzo APPOLONIA, Stefano VOLPIN, Le analisi di laboratorio applicate ai beni artistici policromi, Padova 1999. ARTIOLI 2010 Gilberto ARTIOLI, Scientific Methods and Cultural Heritage. An Introduction to the Application of Materials Science to Archaeometry and Conservation Science, Oxford-New York 2010. Artists’ Pigments 2012 Artists’ Pigments. A Handbook of Their History and Characteristics, 1–4 (eds. Robert L. Feller, Ashok Roy, Elisabeth West FitzHugh, Barbara Hepburn Berrie), Washington 20122. BACCI 1995 Mauro BACCI, Fibre Optics Applications to Works of Art, Sensors and Actuators. B: Chemical, 29/1–3, 1995, pp. 190–196. BALAŽIC 2008 Janez BALAŽIC, Stensko slikarstvo v dobi Luksemburžanov v zahodnem panonskem prostoru, Ljubljana 2008 (unpublished doctoral dissertation). BOGOVČIČ 1995 Ivan BOGOVČIČ, Gotsko stensko slikarstvo. O nastanku, ogroženosti, restavriranju/Gothic Mural Painting. The Development, Endangerment, Restoration, Gotika v Sloveniji. Nastanek, ogroženost, reševanje likovne dediščine/The Origin, Endangerment, and Preservation of Art (ed. Ivan Bogovčič), Ljubljana 1995, pp. 14–21. BROECKE 2015 Lara BROECKE, Cennino Cennini’s Il libro dell’arte. A New English Translation and Commentary with Italian Transcription, London 2015. COCCATO, MOENS, VANDENABEELE 2017 Alessia COCCATO, Luc MOENS, Peter VANDENABEELE, On the Stability of Mediaeval Inorganic Pigments. A Literature Review of the Effect of Climate, Material Selection, Biological Activity, Analysis and Conservation Treatments, Heritage Science, 5/1, 2017, pp. 1–25. CONSENTINO 2015 Antonio CONSENTINO, Practical Notes on Ultraviolet Technical Photography for Art Examination, Conservar Património, 21/6, 2015, pp. 53-62. DE LA RIE 1982 Etienne René DE LA RIE, Fluorescence of Paint and Varnish Layers, 1–3,Studies in Conservation,27, 1982, 142 Anabelle Križnar, Katja Kavkler, Sabina Dolenec pp. 1–7, 65–69, 102–108. HÖFLER 1985 Janez HÖFLER, Stensko slikarstvo na Slovenskem med Janezom Ljubljanskim in Mojstrom sv. Andreja iz Krašc, Ljubljana 1985. HÖFLER 1996 Janez HÖFLER, Srednjeveške freske v Sloveniji. 1: Gorenjska, Ljubljana 1996. HÖFLER 1997 Janez HÖFLER, Srednjeveške freske v Sloveniji. 2: Primorska, Ljubljana 1997. HÖFLER 2001 Janez HÖFLER, Srednjeveške freske v Sloveniji. 3: Okolica Ljubljane z Notranjsko, Dolenjsko in Belo krajino, Ljubljana 2001. HÖFLER 2004 Janez HÖFLER, Srednjeveške freske v Sloveniji. 4: Vzhodna Slovenija, Ljubljana 2004. KRIŽNAR 2006 Anabelle KRIŽNAR, Slog in tehnika srednjeveškega stenskega slikarstva na Slovenskem, Ljubljana 2006. MATTEINI, MOLES 1984 Mauro MATTEINI, Archangelo MOLES, Scienza e restauro. Metodi di indagine, Firenze 1984. Microscopic Analysis 2018 Microscopic Analysis of Wall Painting Techniques. Laboratory Replicas and Romanesque Case Studies in Southern Switzerland, Studies in Conservation, 63/6, 2018, pp. 326–341. MOLE 1984–1987 Izidor MOLE, Poskus analize tehnologije gotskih fresk (I–IV), Varstvo spomenikov, 26, 1984, pp. 89–99; 27, 1985, pp. 121–135; 28, 1986, pp. 189–208; 29, 1987, pp. 123–136. MORA, MORA, PHILIPPOT 2001 Paolo MORA, Laura MORA, Paul PHILIPPOT, La conservazione delle pitture murali, Bologna 20012. NEMEC 1995 Ivo NEMEC, Gotika v Sloveniji. O materialih/Slovene Gothic Materials, Gotika v Sloveniji. Nastanek, ogroženost, reševanje likovne dediščine/The Origin, Endangerment, and Preservation of Art (ed. Ivan Bogovčič), Ljubljana 1995, pp. 35–41. OLTROGGE 2008 Doris OLTROGGE, The Use of VIS Spectroscopy in Non Destructive Paint Analysis. Potential and Limits of the Method for 19th and Early-20th-Century Paintings, Köln 2008. PECCHIONI, FRATINI, CANTISANI 2008 Elena PECCHIONI, Fabio FRATINI, Emma CANTISANI, Le malte antiche e moderne tra tradizione ed innovazione, Bologna 2008. PIRNAT 1972 Miha PIRNAT, Tehnike stenskega slikarstva na Slovenskem, Varstvo spomenikov, 16, 1972, pp. 51–56. POHL 1966 Emil POHL, Raziskava slikarske tehnike na stenskih slikah v Pangrč Grmu, Varstvo spomenikov, 10, 1966, pp. 103–109. 143 Analysis of the Materials and Painting Techniques Used in Medieval Mural Paintings in Slovenia up to 1380 PROKOPP 1983 Maria PROKOPP, Italian Trecento Influence on Murals in East Central Europe, Particularly Hungary, Budapest 1983. RADOCSAY 1977 Dénes RADOCSAY, Wandgemälde im mittelalterlichen Ungarn, Budapest 1977. Reclams Handbuch 1990 Reclams Handbuch der künstlerichen Techniken. 2: Wandmalerei, Mosaik, Stuttgart 1990. SECCARONI, MOIOLI 2004 Claudio SECCARONI, Pietro MOIOLI, Fluorescenza X. Prontuario per l’analisi XRF portatile applicata a superfici policrome, Firenze 2004. Spectroscopy 2021 Spectroscopy, Diffraction and Tomography in Art and Heritage Science (eds. Mieke Adriaens, Mark Dowsett), Amsterdam 2021. STELE 1935 France STELE, Monumenta Artis Slovenicae. 1: Srednjeveško stensko slikarstvo, Ljubljana 1935. STELE 1969 France STELE, Slikarstvo v Sloveniji od 12. do 16. stoletja, Ljubljana 1969. STUART 2007 Barbara H. STUART, Analytical Techniques in Materials Conservation, Chichester 2007. THEOPHILUS PRESBYTER 1979 THEOPHILUS PRESBYTER, On Divers Arts. The Foremost Medieval Treatise on Painting, Glassmaking and Metalwork (eds. John Greenfield Hawthorne, Cyril Stanley Smith), New York 1979. VODNIK 1998 Alenka VODNIK, Tekstilni vzorci v srednjeveškem stenskem slikarstvu na Slovenskem, Ljubljana 1998 (Razprave Filozofske fakultete). ZIMMERMANN 1996 Tanja ZIMMERMANN, Stensko slikarstvo poznega 13. in 14. stoletja na Slovenskem, Ljubljana 1996 (unpublished doctoral dissertation). ŽELEZNIK 1993 Adela ŽELEZNIK, La pittura postvitalesca in Friuli, Carinzia e Slovenia, Trieste 1993 (unpublished typescript). 144 Anabelle Križnar, Katja Kavkler, Sabina Dolenec Analiza materialov in slikarskih tehnik srednjeveškega stenskega slikarstva v Sloveniji do leta 1380 Povzetek Sodoben pristop k preučevanju umetniških del zahteva tudi raziskovanje materialov in postopkov, ki so jih uporab ljali umetniki pri njihovem ustvarjanju. Na področju stenskega slikarstva to vključuje znanje o uporabljenih pigmentih, razlikovanje med slikanjem na svež in na suh omet, apneno ali mešano tehniko in študij slikarskega postopka od pripravljalne risbe do končnega modeliranja. Te informacije skupaj z umetnostnozgodovinsko študijo omogočajo popoln vpogled v umetniško delo in umetnikov način ustvarjanja, kar omogoča boljšo primerjavo med različnimi deli, umetniki ali delavnicami. Osnovni pristop je analiza materiala, ki je lahko neinvazivna ali invazivna; slednja temelji na odvzemu majhnih vzorcev, ki se nato analizirajo z različnimi laboratorijskimi tehnikami, kot so optična mikroskopija (OM), skenirna elektronska mikroskopija z energijsko disperzno rentgensko spektroskopijo (SEM-EDX), rentgenska fluorescenca (XRF), rentgenska difrakcija (XRD) ali ramanska spektroskopija, ki so najpogostejše. Doslej je bilo raziskanih več kot 40 izbranih srednjeveških fresk po vsej Sloveniji, ki so potrdile ozko, praviloma naravno paleto anorganskih pigmentov, primernih za fresko posli kavo, v redkih primerih so bili najdeni tudi svinčevi pigmenti, ki pa so večinoma potemneli. Glavna slikarska tehnika je freska, večinoma v kombinaciji s secco ali apneno tehniko, slednja je v nekaterih primerih tudi glavna. Postopek slikanja se od poslikave do poslikave razlikuje in razkriva umetnike različnih slikarskih in tehničnih spretnosti. Delo še vedno poteka.