The Effect of Preservative Interventions on the Chemical-
Physical and Structural Characteristics of Panel Painting
Creators: name: Hayashi, Mikiko <1976>
Publisher: name: Alma Mater Studiorum - Università di Bologna
Year: 2009
Subjects: CHIM/12 Chimica dell'ambiente e dei beni culturali

description: This work studies the impact of two traditional Romanian treatments, Red Petroleum and Propolis, in
terms of real efficiency and consequence on the wooden artifacts. The application of these solutions is still a
widely adopted and popular technique in preservative conservation but the impact of these solutions is not well
known. It is important to know the effect of treatments on chemical-physical and structural characteristics of the
artifacts, not only for understanding the influence on present conditions but also for foreseeing the future
behavior. These treatments with Romanian traditional products are compared with a commercial antifungal
product, Biotin R, which is utilized as reference to control the effectiveness of Red Petroleum and Propolis.
Red Petroleum and Propolis are not active against mould while Biotin R is very active. Mould attack is
mostly concentrated in the painted layer, where the tempera, containing glue and egg, enhance nutrition
availability for moulds. Biotin R, even if is not a real insecticide but a fungicide, was the most active product
against insect attack of the three products, followed by Red Petroleum, Propolis and untreated reference.
As for colour, it did not change so much after the application of Red Petroleum and Biotin R and the
colour difference was almost not perceptible. On the contrary, Propolis affected the colour a lot. During the
exposure at different RH, the colour changes significantly at 100% RH at equilibrium and this is mainly due to
the mould attack.
Red Petroleum penetrates deeply into wood, while Propolis does not penetrate and remains only on the
surface. However, Red Petroleum does not interact chemically with wood substance and it is easy volatilized in
oven-dry condition. On the contrary Propolis interacts chemically with wood substance and hardly volatilized,
even in oven-dry condition and consequently Propolis remains where it penetrated, mostly on the surface.
Treatment by immersion has impact on wood physical parameters while treatment by brushing does not
have significant impact. Especially Red Petroleum has an apparent impact on moisture content (MC) due to the
penetration of solution, while Propolis does not penetrate so much and remains only on surface therefore
Propolis does not have so much impact as Red Petroleum. However, if the weight of the solution penetrated in
wood is eliminated, there is not significant difference in MC between treated and untreated samples. Considering
physical parameters, dimensional stability is an important parameter. The variation of wood moisture content
causes shrinkages/swelling of the wood that polychrome layer can only partially follow. The dimension of
wooden supports varied under different moisture conditioning; the painted layer cannot completely follow this deformation, and consequently a degradation and deterioration caused by detachment, occurs. That detachment
affects the polychrome stratification of the panel painting and eventually the connections between the different
layer compositions of the panel painting.