Abstract:
The introduction of LV-SEM as a tool in conservation science
has greatly improved the possibilities of analysing a wide variety of unique
specimens in a non destructive manner. The poster presents a number of
examples of how LV-SEM can give valuable information to conservators, archaeologists
and curators with minimum damage to the artefact.
Easel paintings:
In order to choose the proper method of conservation of a painting
it is important for the conservator to investigate the layered structure.
Analysis of the paint layers can give results that are helpful in dating
the painting and revealing fraud. Normally you are only allowed to
take very small samples from pieces of art. Therefore microscopic methods
are preferred for the analysis.
Cross-sections of paint samples can be examined in reflected light
and with SEM/EDS the different elements in the layers can be detected.
With this method many inorganic colours can be identified. After you have
examined the sample with LV-SEM you can immediately microscope it
in reflected light, as you do not have the opaque layer of carbon coating
on the surface, which is necessary for conventional SEM.
We give examples from paintings recently analysed at the Department
of Conservation at the National Museum of Denmark.
Wall paintings:
Many wall paintings are found in churches with big fluctuations in
temperature and humidity. Some of the main problems in conservation of
wall paintings are deterioration of pigments, efflorescence of salt on
the surface and flaking of paint layers. LV-SEM is a powerful tool in studying
the identity of deteriorating pigments and salts from wall paintings.
Lime water consolidation of a wall painting in Avnsø church, Denmark was examined. During the experiment the painting had been treated with lime water continuously until the wall was saturated. The effect of consolidation was revealed with backscattered electron images showing growth of calcite crystals in the paint layer.
The LV-SEM technique has a wide range of other applications in conservation science ranging from the study of corrosion products in situ on the surface on small artefacts to fibre analysis of untreated archaeological textiles. The primary advantage of this technique is the possibility of working with uncoated samples which can be preserved for further use.
The presented experiments were performed on a JEOL 5310 LV SEM with a Link EDS system using a Si(Li) ATW detector. The instrument is located at the School of Conservation, Copenhagen, Denmark.
If you have comments on this home page, or any kind of professional interest in our work please feel free to contact me at ulrich@alfhiem.dk or phone me at +45 33 47 35 28.