Document Type : Research Paper
Authors
1 Associate professor, Faculty member of Research Institute of Cultural Heritage and Tourism (RICHT), Tehran, Iran
2 Assistant professor, Faculty of Cultural Materials Conservation, Tabriz Islamic Art University, Tabriz, Iran
3 Restoration expert, The Research Center of Cultural Artifacts Conservation and Restoration (RCCCR)
4 Department of Art and Architecture, Payam-e Noor University, Tehran, Iran
Abstract
Background and objectives: Painting on wood became popular in Iran during the Safavid period and reached its peak during the Zand and Qajar periods. The art of painting and writing inscriptions on wood as one of the unique arrays in Iran has been forgotten and their technical and pathological studies will greatly help to preserve and perpetuate such works. Preservation of wood in historical buildings, where color arrays are also applied, is a complex task. The challenge of this work is related to the multiple material characteristics of the work, the type of interventions and the selection of protective chemicals that should be considered in these works. In fact, by fully understanding the work, it is possible to provide a protection solution for it. The purpose of this article is to know the materials, structure and damage of the different layers of the historical headstones of the Taqvi House in Gorgan.
Methodology: The wooden lion heads of the Taqvi House in Gorgan, which have written inscriptions along with plant motifs and frames, are the study samples of the current research. The type and amount of the sample was chosen according to the existing uncertainties as well as the test method. In total, four wood samples and four paint samples were prepared. For the technical study of these works, transmission microscope, Dino-Lite plus digital microscope, scanning electron microscope (SEM) equipped with EDS detector were used. Also, under standard laboratory conditions, mushroom cultivation and wood acidity were measured.
Results: The black spots in the examination with a digital microscope indicate the presence and growth of biological factors on the surface of wood, which were sampled in a part of them to cultivate and identify the fungi. Initial observations with a digital microscope indicate the destruction of wood components caused by biological factors and the reduction of wood strength and cohesion. In the first investigation, according to the cross-sections of all the samples (three samples), it was found that the samples are broad-leaved woods. The vessels are evenly distributed. In the tangential section, single-celled and multi-celled wood rays can be seen, the width of which reaches about 25 cells. The size of the vessels is almost the same and of a homogeneous and scattered type of vessel. In this sample, two to four vessels are stuck together. The average size of the vessels was measured to be 59 micrometers. Also, the frequency of vessels per square millimeter was calculated to be 130 vessels per millimeter on average. In two samples 2021.G.T.3 and 2021.G.T.8, the vessels are heterogeneous, separated and their cross section is relatively round. Heterogeneous holes and part of the aperture can be seen and some of them are tiled. The diameter of the vessels is specific from spring and summer wood. In the tangential section, single-celled or multi-celled wood rays are observed. In the continuation of the studies, the study samples were examined with a scanning electron microscope with different magnifications. The cell wall in a sample is weakened and is collapsing. Also, the growth of fungi can be clearly seen among the wooden structure. In the other two samples, the cellulosic walls are severely damaged and we see dissociation and rupture between the cellulosic layers.
Conclusion:The results of this study showed that the wood used for historical lion heads is beech and mazo wood. Also, fungi such as Aspergillus terius, Alternaria, Aspergillus niger and Cladosporium were identified in the wood structure. In the following, the destruction of the cell wall and the decay of the wood structure were identified. Also, azure blue, syringe red, white flowers, as well as a mixture of carbon black and iron black colors have been used on historical wood as patterns and writings. This study can be very important for the proper preservation of historical wooden works of Gorgan region.
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