Painting Degradation from Inside Wooden Churches Achieved in the Period 1750–1850 ^†

1. Introduction

The wooden churches made between 1750 and 1850 have as decorative elements paintings made on wood or wooden panels. The materials used to make them are generally pigments that existed on the market at that time [1,2]. At present, many of these need restoration and conservation work. For this aim, the type of degradation must be established.

2. Materials and Methods

On the wood-painted surfaces, the biological degradation was established applying a non-destructive methodology, based on sampling with a cotton swab, and followed by application on specific culture media and microscopic identification of microorganisms.

3. Results and Discussion

Visual analysis of painted wood reveals the wood panels degradation due to insect activities. The species involved in this process can be Anobium punctatum; Stegobium paniceum; Xestobium rufovillosum; Dinoderus minutes; Euophryum confine; Lyctus brunneus and Nacerdes melanura [3,4]. The main microorganisms identified on painted surfaces belong to the Dematiaceae Family and, respectively, to the Phylum Basidiomycetes. In the microbiology lab, only spores of Epicoccum nigricum and possibly of Phanerochaete chrysosporium were identified, without the mycelium presence. No visible infection was observed on the painted wood structure, and for this reason, we concluded that the wood panels painted do not exhibit microbiological infections. That is the reason for which we recommend that treatment against insects occurs before painted wood restoration. The treatments must be made using a non-destructive method to keep the painted images from the wood panels. From this point of view, the literature indicates that the treatments with carbon dioxide in concentrations of 50–80% in the air are able to destroy the insects from the wood in a maximum 96 h. In this way, the eggs, larvae, pupa, and the adults of species such as Stegobium paniceum are destroyed [5]. Other scientists recommend inhibiting the development of the microfungi and insects by using gamma radiation at a dose of 10 kg [6]. In this case, all species responsible for wood degradation are destroyed. It is important to mention that these treatments do not offer protection in long term; for this reason, the treatments must be repeated at different time lengths.

4. Conclusions

The pictures painted on the wood from wooden churches built in the period 1750–1850 exhibit degradation due to biologic agents, mainly due to insects, and sometimes due to the presence of microorganisms. Physical and/or chemical treatment can be applied to destroy or inhibit these species, but this must be repeated from time to time.