Stained Glass - Art at the Glass Surface
Cambridge - Monday 4th and
Tuesday 5th September 2017

Edyta Bernady
<[email protected]>

article posted 17 May 2017

Edyta Bernady is a PhD student in Jan Matejko Academy of Fine Arts in Cracow, Poland. She holds a Master’s Degree in Conservation and Restoration of Works of Art from Jan Matejko Academy of Fine Arts and Bachelor’s Degree in Biology from Jagiellonian University. In 2015, she was granted a “Diamond Grant” funded by the Ministry of Science and Higher Education. Her Master Thesis entitled: The study by modern analytical techniques and conservation of 15th century stained-glass window Throne of Grace from Dominican monastery in Cracow was awarded in contest organized by the General Conservator of Monuments and Association of Monument Conservators. During Ph.D. studies she focuses on research, documentation and conservation of the paint layers on medieval stained-glass panels.

Analysis of technology and state of preservation of medieval and modern paint layers on two stained-glass panels from the Dominican Monastery in Cracow, Poland
Edyta Bernady*, Marta Kamińska, Michał Płotek, Małgorzata Walczak

Jan Matejko Academy of Fine Arts in Kraków, Faculty of Conservation and Restoration of Works of Art

Two stained-glass panels from the Dominican Monastery in Cracow, depicting “the Throne of Grace” and Saint Mary from “the Annunciation” are subjects of analytical research and conservation treatment. The panels are dated back to the 1st half of the 15th century and are considered as made in local stained-glass workshops. They belong to a collection of 21 medieval stained-glass panels preserved in the monastery. Around 1895 Stanisław Wyspiański (a famous Polish Art Nouveau artist) designed the reconstructions and ornamental borders for all the panels, which were accomplished during the next couple of years.

The general aim of the research was to gain knowledge about the technology and condition of the panels. However, considering the different level of deterioration of medieval and modern paint layers, a much deeper analysis was necessary. The goal was to obtain information on the structure, the elemental composition and the morphology of the paint layers. The final objective was to determine whether the consolidation of the paint layers was required and what was the reason of the different condition between modern paint layers. For elemental analysis MA-XRF and SEM-EDS were conducted. SE and BSE images provided information about pigment grains, flux grains and inter-diffusion zone. The texture of paint layers was also shown by means of a digital microscope Hirox RH2000.

The obtained results allowed the comparison of the paint layers. The amount of flux (PbO) relative to the pigment was established. In the medieval paint it varied from 28% to 65% wherein in the samples from the panel depicting Saint Mary, the amount of flux was lower. In those samples, the layer was more granular and microcracks were visible.

The analysis shown that the modern panes were painted with several paints differing in elemental composition and the amount of flux.

In the case of the panel depicting Saint Mary, where the paint layer was granular, not well vitrified and microcracks were present, a local consolidation may be necessary. However, in “the Throne of Grace”, where the paint layer is better adhered and vitrified, optimal museum conditions should be sufficient to slow down the degradation. However, further investigation and experiments have to be made to determine the impact of the composition on the durability of modern paint layers. The research was funded by the Polish Ministry of Science and Higher Education, Diamond Grant (project no. 0164/DIA/20015/44).