Material characterisation of a painted beehive panel by advanced spectroscopic and chromatographic techniques in combination with hyperspectral imaging

Lea Legan,John Gilchrist,Irena Kralj Cigić,Matija Strlič,Polonca Ropret,Maša Kavčič,Klara Retko,Bojana Rogelj Škafar,Yingwang Gao

doi:10.1186/s40494-020-00468-y

Abstract

In this study, a painted beehive panel from the collection of the Slovene Ethnographic Museum was examined with respect to its material composition with the aim to reveal the painting technique. Due to the state of degradation due to outdoor weathering (UV irradiation, rainfall, extreme temperature and humidity fluctuations), as well as past conservation interventions, the object represented a complex analytical challenge. We aimed for non-invasive techniques (FTIR in reflection mode, Raman spectroscopy and hyperspectral imaging in the range of 400–2500 nm); however, in order to explore paint layers, cross-sections were also analysed using Raman spectroscopy. FTIR spectroscopy in transmission mode and gas chromatography coupled to mass spectrometry were also used on sample fragments. Various original materials were identified such as pigments and binders. The surface coating applied during conservation interventions was also characterised. Additionally, organic compounds were found (oxalate, carboxylate), representing transformation products. The potential use of Prussian blue as a background paint layer is discussed.

Highlights

Painted beehive panels are an original folk art form unique to certain Slovenian-speaking regions
The objects had to withstand outdoor weathering conditions including intensive UV irradiation, rainfall, extreme environmental fluctuations, as well as mechanical degradation, which resulted in extensive degradation of many beehive panels
For characterisation of drying oils gas chromatography coupled to mass spectrometry (GC–MS) is often used to determine the palmitic-stearic and azelaic-palmitic acid ratios, on the basis of which the most frequently used drying oils can be reliably identified in the case of undegraded materials [13, 14]

Summary

Introduction

Painted beehive panels are an original folk art form unique to certain Slovenian-speaking regions. 13 × 30 cm) decorated the fronts of wooden beehives stacked under a roof, forming an open-air apiary or “bee-house”. The objects had to withstand outdoor weathering conditions including intensive UV irradiation, rainfall, extreme environmental fluctuations, as well as mechanical degradation, which resulted in extensive degradation of many beehive panels. Beekeeping is meaningful connection between people and the structured world of the bee society. They build special housing for bees, take care of them and collect the products of their activities. Beehives, as bee houses with painted panels, became a reflection of people’s own views of themselves and the world in which they lived and struggled to survive.

Methods

Results

Conclusion