by Jaan Lehtaru
St. John’s Church in Tartu is most famous for its terracotta figures that inhabit the interior and exterior of the church, remnants of approximately 2,000 it is thought to have had in the Middle Ages. There is no other building in the entire European Gothic tradition that could in any significant way compete with this church in the number, variety, and artistic quality of the terracotta sculptures. For more see http://www.estinst.ee/Ea/heritage/alttoa.html.
The National Archives of Estonia holds a collection of the paint samples of the figures.
In the 1950s and 1960s, art historian Olev Prints (1915–1996) explored and documented in great detail the condition of figures. Besides drawing and describing them he took ca 200 paint samples from them. The collection of Olev Prints, given over to the archives in 2006, is a source of information of extraordinary value since it allows the researchers today and in the future, by applying different methods, to discover the medieval colours and decorating techniques.
A vivid example of the research done on this subject is the master thesis by Johanna Lamp: “Olev Prints and the lost colours of Tartu St. John’s church. About the polychromy of medieval architectural sculpture” (2013). It was supervised by Hilkka Hiiop and Anneli Randla at the Estonian Academy of Arts. The paint samples were analysed by using infrared spectroscopy (FT-IR spectrometer) and Scanning Electron Microscopy with X-ray microanalysis (SEM-EDS). The analysis of pigments and binders was conducted in collaboration with the UT Institute of Chemistry.
Recently the search for lost colours was continued at the archives. The new efforts of the researchers focus on mapping all the pigments used on the terracotta figures as well as the painting techniques. In addition to the equipment of the chemistry lab of the university also X-ray fluorescence portable spectrometer (XRF) owned by the Estonian Environmental Research Centre was involved. This allows you to take the analyser to the sample instead of bringing the sample into the lab and so the records are not damaged.
In the future, the research will allow us to view the digital images of the terracotta figures in the whole range of their original colours and beauty.
The church was re-opened in 2005. The story of its renovation is presented at http://www.icomos.org/quebec2008/cd/toindex/77_pdf/77-NSdk-292.pdf.