Project: Complexion and Significance - The Human Image in Panel Painting from 200 to 1250 in the Mediterranean
Project term: 1st April, 2014 – 30th June 2017
Funded by the „Federal Ministry of Education and Research“ according to the directive „Die Sprache der Objekte – Materielle Kultur im Kontext gesellschaftlicher Entwicklungen“
funding code: 01UO1401
Technical University of Munich – Chair of Restoration, Art Technology and Conservation Science
Zentralinstitut für Kunstgeschichte – Forschungsstelle Realienkunde, Munich
Bayerische Staatsgemäldessammlungen – Doerner Institute, Munich
Other participating institutions:
Opificio delle Pietre Dure (Ministero dei Beni e delle Attività Culturali), Florence
Galleria degli Uffizi, Florence
Museo Nazionale di Villa Guinigi, Lucca
Museo Nazionale di San Matteo, Pisa
Musei Vaticani, Cittá del Vaticano
Monastery Santa Maria del Rosario, Monte Mario, Rome
L'Istituto Superiore per la Conservazione ed il Restauro, Rome
Staatliche Museen Preußischer Kulturbesitz, Antikensammlung und Rathgen-Forschungslabor, Berlin
Akademisches Kunstmuseum, Bonn
Liebieghaus, Skulpturensammlung, Frankfurt a. M.
Staatliche Antikensammlungen und Glyptothek, München
Martin von Wagner Museum, Würzburg
Holy Monastery of Saint Catherine at Mount Sinai
All the panel paintings were documented in high resolution using various photographic methods - VIS photography, raking light photography, UV fluorescence photography and infrared photography. The example of the icon with the Crucifixion of Christ (Holy Monastery of Saint Catherine at Mount Sinai, 47 x 25 x 1 cm) shows how different kinds of information were revealed and documented.
The use of the pigment Egyptian Blue was detected on mummy portraits by means of an infrared filter (VIL photography). Egyptian blue is one of the oldest, artificially produced colorants.
The pigment luminesces in the VIL image: the green of the wreath is a mixture of Egyptian blue and yellow colorant. The whites of the eyes were shaded with Egyptian Blue. The garment also contains Egyptian Blue.
A portable stereomicroscope was used on site to examine the complex paint layers of the panel paintings in microscale.
To clarify the layer sequence, a tiny piece of paint is taken, embedded in resin, cut and polished transversely across the layers. In cross-sections one sees the layer sequence of the painting. The layers are optically differentiated by means of various light microscopic examination methods. The elements of the colorants can be analyzed by a scanning electron microscope (SEM).
Mummy Portraits from Egypt
During the 19th century, travelers, dealers, and early Egyptologists brought a large number of so-called portrait mummies to the attention of European collectors. They were interested mainly in the painted portraits rather than in the bulky embalmed bodies. Consequently, in today’s museums one mostly finds only the cut-out portraits of the deceased. The portrait mummy trend arose in the oases of Egypt during the Imperial Roman era, from the 1st century to the 3rd century, under Greek influences.
Based on visual characteristics, the examined antique panel paintings could be attributed to three painting techniques: the Antique Tempera Technique, the Encaustic and the Antique Cold Wax Painting.
Water based binders such as egg, glue or gums were used in the Tempera Technique. These colors were usually applied thinly. In addition to the Tempera Technique, beeswax was also used as a binder.
The so-called Severan Tondo is the only known panel painting from Antiquity that depicts an imperial family. The Tondo came – like the mummy portraits – from Egypt and shows the emperor Septimius Severus (193–211) with his wife Julia Domna and their sons Geta and Caracalla. The face of Geta was scratched out by order of his brother. Painted portraits like this existed in high numbers in Antiquity and hung in offices, shops and also sanctuaries.
The so-called Severan Tondo, painted in Antique Tempera Technique, shows a vibrant, fast and experienced approach to painting. Bright shades were used over dark ones and reversed. The modeling of the flesh tones was achieved by overlapping and juxtaposing numerous layers of translucent paint. Thin glazes were added on top of impasto brushstrokes late in the painting process - they let the earlier layers shine through, so that the superimposition creates additional shades and at the same time induces volume and plasticity.
Schematic representation of the paint layers of an eye in Antique Tempera Technique, using the example of: Mummy portrait of a man (2nd half of the 2nd century – around 200), Würzburg, Martin von Wagner-Museum, Inv. H 2196.
 base Color
 light yellow-ocher outline (first modeling of the shades)
 orange-brown (second modeling of the shades)
 cool, light pink Highlights
 pink (lower eyelid, eyelid crease]
 light, red-brown contouring
 dark, red-brown Elaboration
 dark brown (iris, eyelid crease)
– gray in three nuances (modeling of the eyeball)
 bright red-brown (iris)
 white light-point
Schematic Diagram for the Purification and Pretreatment of Beeswax
Recipes in ancient sources, e.g. by Pliny the Elder (Naturalis historia, 1st century) or Dioscorides (De materia medica, 1st century), served as the basis for the reconstructions.
The descriptions in the sources leave much room for interpretation; for example, when boiling wax with seawater and lye different end products can result. It is still unclear which product(s) was (were) used for painting.
Although the mummy portraits still look beautiful today, the beeswax in their paints has altered significantly after nearly 2000 years of ageing in the Egyptian climate. Gas chromatograms of fresh beeswax and beeswax from a mummy portrait reveal that the components with low boiling points have evaporated. In the gas chromatograms the individual compounds are separated by boiling point: the more volatile components appear on the left, while compounds with lower volatility appear on the right.
Because the alterations caused by ageing are superimposed over alterations induced by the Treatment described on the last slide, it is not possible today to determine with certainty which product (a, b or c) was initially used.
The Greek-Orthodox Monastery of Saint Catherine at Mount Sinai in Egypt was founded in the 6th century and conserves one of the world’s oldest and largest collections of icons. Two research campaigns were carried out in 2016 and 2017 for the ISIMAT project.
For the ISIMAT project, eleven panel paintings were examined. They may be dated to between the 7th and the 10th centuries. Stylistically they belong to either the Byzantine or the local tradition. The painting technique was classified as the medieval tempera technique on the basis of optical criteria.
The panel shows the oldest known painted depiction of the dead Christ on the cross. The painter didn’t differentiate the flesh tones of the dead from the living or the male from the female figures. Obviously, his goal was to portray Christ at the moment when he overcame death more than it was to characterize the transience of his human body.
The composition of this preserved fragment representing the crucifixion is reduced to the main figures which are shown isolated in front of a golden ground. The painterly conception of the faces has the same quality as works attributed to the masters employed at the imperial court in Constantinople.
Composition of Mary’s Face
 red glaze (lips and nose)
 white highlights
 black lines
 red-brown lines
 green-brown lines
 dark pink accents
 pink accents
 white areas of light (in several layers)
 ocher shadow (eyelids, nose)
 dark green shadows
 yellowish green underpainting
 white ground layer
 wooden support
The panel, which was probably the left wing of a triptych, is one of the oldest icons preserved in the Holy Monastery of St. Catherine at Mount Sinai. The paintings show St. Athanasius the Great (died 373), the Archbishop of Alexandria, who is considered to be one of the most influential church teachers, as well as St. Basil the Great (died 378), Bishop of Caesarea and Metropolitan of Cappadocia, who was one of three Cappadocian church fathers. St. Basil’s rules are considered to be the basis for monastic life especially in the Eastern World. Both Church teachers embody the ascetic type of a saint, characterized by elongated features and the expressive description of their physiognomy.
This icon is also painted without a white ground layer: The bright colors were applied directly onto the wooden support. For the haloes yellow paint containing ocher and large orpiment particles was used. The flesh tones were modeled using only a few colors (white, red, black a little pink) over a layer of ocher underpainting.
Reconstruction of the Process of Painting the Face of St. Athanasius
 blue background
 yellow color of the halo
 brown underpainting of the figure
 first highlights of the flesh tones in two layers
 brown underpainting of the hair
 black lines
 gray shading of the eyeballs
 bright red accents
 final white accents
 yellow lines and decoration of the halo
 shading of the blue background
 final state
Since 1613, the so-called Salus Populi Romani, has been kept in the baroque retable of the Cappella Paolina in Santa Maria Maggiore. It has been known as the Salus Populi Romani since the 19th century. The figures are rendered in front of gilded background. Furthermore, the now red halos were originally gilded. The painting was executed in Tempera Technique.
Over a green base color, the flesh is modelled with many thin paint applications by single brushstrokes. The flesh tones were omitted in sections to allow the green base layer to form the shadows, which were deepened with transparent brown paint layers. Brown, vermilion red, and white brushstrokes complete the painting.
Procession with the icon Salus Populi Romani in Rome, 1954
This cross-section of Christ’s flesh in an Italian crucifix reveals a complicated build-up of many layers. The ocher to white flesh tones were laid in (underpainted) with green. On top there is a varnish, which can be discerned by its bright fluorescence in UV light.
This particular stratification of colors is not representative of all flesh tones. In medieval Tuscany at least three different traditions for painting flesh tones can be observed.
Traditions for Painting Flesh Tones in Medieval Tuscany
In Tuscany different painting traditions can be ascertained. The methods of painting share the fact that the modeling of the flesh tones occurs over a colored base layer. This painting layer, referred to as the 'base color', is executed in different shades: from bright orange and yellow-pink to pink and green.
Over the base color, modeling is built up in different ocher-colored to white skin colored mixtures, light and shadow colors. The base color is left visible in places under the modeling and is thus part of the painting.
Flesh Tones with a Bright Yellow-Orange Base Color
The face of Christ from the Croce di Berlinghiero, Lucca, is painted on top of a thin, bright yellowish base layer. Over this, the cheeks, forehead and chin are modeled with very fine, translucent strokes of cinnabar. Broader, opaque white brush marks form the highlights.
The delicate modeling of the face was created by layers of yellow transparent paint (glazes). The painting seems to shine as if it were executed over gilded ground.
Flesh Tones with a Yellow-Ocher to Warm-Pink Base Color
The modeling of the flesh tones of the face of Christ on the Croce di San Sepolcro results from the double application of shadow- and light colors, as well as from the red of the cheeks over the yellow-ocher to pink base color.
This technique is based on the painting tradition described in the 'Schedula diversarum Artium'.
Flesh Tones with a Cold-Green Base Color
Giunta Pisano modeled the face of Christ on a cold-green colored base layer. The bright, almost white skin color was painted with fine brushstrokes and applied gradually more densely from the darker to the brighter parts. Various transparent, warm-green to red-brown shadow colors create the soft and painterly transitions.
The painting technique with the cold-green base color may have been of eastern origin. It is described in the “Liber colorum secundum Magistrum Bernardum” as “incarnatura greca”. This manner of painting is first named by Cennini (early 14th century) as the modern or Italian style for painting flesh tones.
Different Base Colors on the Same Panel Painting
While Berlinghieri built the flesh tones of the Christ vivens of his “croce dipinta” on an orange-colored base layer, he modeled the accompanying figures over a green base color.
This green tone should not be associated with the painting tradition of Giunta Pisano, but with the painting instructions provided in the “Schedula diversarum”. There it is described how the faces of pale and suffering people are to be painted on a green base color.
Flesh Tones with a Brown-Green Base Color
Cross-sections of the original painting of the St. Luke Icon from Freising (today overpainted) show a brown-green base color in the areas of flesh tones.
Flesh tones with a brown-green base color were not yet present in panel paintings in Rome and Tuscany.
This finding supports the thesis that this style of painting is rooted in a Byzantine tradition. A brown-green base color is described in the “Painter's Book of Mount Athos” (also “Hermeneia”) by the Greek painter Dionysius of Phourna.
The painting techniques for the presentation of the flesh tones were compared to passages and instructions from selected medieval sources.
The temporal location and the spatial dissemination of painting practices, such as through the migration of the artists, are reflected not only in the works but also in the written traditions:
“Schedula diversarum Artium”, an encyclopedic art technical collection in three books from various sources, from the first half of the 12th century
“painter's book from Mount Athos” (also “Hermeneia”) of the Greek painter Dionysius of Phourna (died after 1740), as a late summary of medieval Byzantine techniques of icon painting
“Liber colorum secundum Magistrum Bernardum quomodo debent distemperari et temperari et confici”, the painting treatise of the master Bernardo from Morimondo (Milan) from the 13th century
“Il libro dell'arte”, the famous painter's book of Cennino Cennini, Padova, early 14th century
The results of the examinations have already been presented in a scientific publication
Lehrstuhl für Restaurierung, Kunsttechnologie und Konservierungswissenschaft, Technische Universität Munich
Forschungsstelle Realienkunde, Zentralinstitut für Kunstgeschichte, Munich
Doerner Institut, Bayerische Staatsgemäldesammlungen
Opificio delle Pietre Dure, Florence
Title: Inkarnat und Signifikanz – Das menschliche Abbild in der Tafelmalerei von 200 bis 1250 im Mittelmeerraum
Studien aus dem Lehrstuhl für Restaurierung, Kunsttechnologie und Konservierungswissenschaft, Technische Universität München, Fakultät für Architektur
Veröffentlichungen des Zentralinstituts für Kunstgeschichte in München, vol. 42
Schriften der Forschungsstelle Realienkunde, vol. 3
Authors of the texts:
Catharina Blaensdorf (Technical University of Munich – Chair of Restoration, Art Technology and Conservation Science)
Patrick Dietemann (Bayerische Staatsgemäldessammlungen, Munich – Doerner Institute)
Luise Sand (Technical University of Munich – Chair of Restoration, Art Technology and Conservation Science)
Yvonne Schmuhl (Zentralinstitut für Kunstgeschichte, Munich – Forschungsstelle Realienkunde)
Cristina Thieme (Technical University of Munich – Chair of Restoration, Art Technology and Conservation Science)
Esther Wipfler (Zentralinstitut für Kunstgeschichte, Munich – Forschungsstelle Realienkunde)