Norwegian University of Science and Technology
Department of Chemistry
 

Chemical investigation of cultural heritage artifacts and monuments

Participants

Lise Kvittingen (Professor). E-mail: lise.kvittingen@chem.ntnu.no
Florinel-Gabriel Banica (Associate Professor). E-mail: florinel.g.banica@ntnu.no. Retired in 2016.
Kidane Fanta Gebremariam, PhD.  E-mail: kidane.fanta@ntnu.no. After graduating in 2016, Kidane moved to the  University of Stavanger, Archaeology Museum (link).
Emilio Catelli, PhD. E-mail: emilio.catelli@ntnu.no. After graduating in 2016, Emilio earned a postdoctoral position at the University of Bologna, Italy.
 

Objectives

• What are the variations in the painting techniques used in the different paintings?
• What materials have been used and what technologies were utilized in their preparations? What can be suggested about the origin of the materials used?
• What kind of degradation processes have happened\are going on in some of the paintings?
• What are the current conservation states of the various paintings considering the chemical composition of the painting materials?
• In what way is the environment affecting the paintings?

Current interests

Mural paintings in medieval Ethiopian churches (Paper 1; Paper 2)
Investigation of rock art at Honnhammer (more)
Investigation of illuminated manuscripts (more) by various methods including hyperspectral analysis.
Degradation of bronze archaeological and fine art artifacts (more)
Salt efflorescence in ancient timber houses at the Sverresborg Musem in Trondheim (Published paper)

Methods

The non-destructive investigations are the most preferred ones as keeping the integrity of the cultural heritage is given the utmost priority all the time. Analysis of pigments, surface treatment materials like varnish, etc. is carried out in situ on the paintings using a portable XRF analyser, digital microscopes and other appropriate handheld and non-destructive instruments. Following the survey of the elemental composition of the different colours in selected paintings, micro-samples are collected to study their micro stratigraphy, the composition of pigments, plaster layers, surface treatments, etc. Embedded in acrylate resin and polished, the resulting cross-section samples are subjected to examinations by Polarized Light Microscopy (PLM), Fluorescence Microscopy and Scanning Electron Microscopy-Energy Dispersive X- ray Spectroscopy (SEM-EDS). The unambiguous identification of painting materials needed not only elemental analysis but also molecular, mineralogical and structural information as can be obtained from X-ray diffraction (XRD) and micro-IR spectrophotometry and Raman Spectroscopy. Considering the multilayer and complex mixtures of compounds in micro-samples that can be made available, reasonable spatial resolution is highly demanded. To this end, attempts will be made to use advanced instrumental methods of analysis for morphological and chemical composition investigations.

Chromatographic techniques like Gas-Chromatography- Mass-Spectrometry (GC-MS), High performance liquid chromatography (HPLC) will be used for identification of binding media, varnishes and dye stuffs used in different parts of the paintings.

Results expected and their significance in the respective field of research

From these investigations, we expect reliable identification of the different pigments, plasters, extenders, and degradation products in the painting samples. By employing a combination of analytical techniques, adequate identification of the compounds can be achieved even when found in relatively low concentrations. Attempts are also made to identify the physical and chemical alteration processes in the disfigured portions of the painting layers.

The documentation of the materials and paintings techniques of these paintings contributes to comparative art historical studies. The technical characterization of the painting materials and the study of deterioration processes plays  a great role in the efforts to be exerted in their conservation and restoration.

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Last update: 2017.01.05