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Research - Conservation Research
Introduction | Projects | Glossary
Glossary
Conservation
Conservation is an umbrella term for the profession that is responsible for the physical care and technical analysis of cultural material and its environment. Conservation activities include restoration, preservation, examination, research, advice, treatment, preventive conservation and training.
Restoration
Restoration is defined as treatment that aims to return an art work to a known earlier state. Establishing the authenticity of a known state is a key part of this activity and often involves technical and other research.
Preservation and preventive conservation
Preservation and preventive conservation involve activities that aim to protect or maintain an art work in its current condition — that is, to minimise chemical and physical deterioration or loss of information. This can include individual treatment on an art work such as rehousing photographs, as well as activities such as establishing a stable environment and determining procedures for handling, packing and transport.
Visible light photography
Visible light is the part of the electromagnetic spectrum which is visible to the human eye — colours from red to violet make up ‘white’ light. Works can be photographed in normal, raking (oblique) or transmitted (lit from behind) light to show up different characteristics.
Infra-red reflectography
Infra-red energy is heat, and it occurs at wavelengths longer than 760 nanometres — just beyond red in the electromagnetic spectrum. Infra-red imaging relies on the selective absorption of heat by pigments and is most useful for detecting underdrawing. Many earth-based pigments (for example, charcoal in drawing layers) are visible using an infra-red detector. At the Queensland Art Gallery we use a Hammamatsu Vidicon™ system.
Infra-red reflectography of the Master of Frankfurt,
Virgin and Child with Saint James the Pilgrim,
Saint Catherine and the Donor with Saint Peter,
in process by Mandy Smith, Conservation Technician, QAG
Photograph: Matthew Kassay
X-radiography
X-rays are the part of the electromagnetic spectrum invisible to the eye and useful for mapping materials of different atomic weight. The larger the atoms from which a material is made, the whiter that material appears on an X-ray film. X-rays are particularly useful for imaging lead white design areas in paintings, and metal armature inside sculpture. There are conservators licensed to undertake radiography of art works at the Queensland Art Gallery.
Ultra-violet photography
Ultra-violet light is short wavelength energy, just beyond violet in the electromagnetic spectrum and invisible to our eyes. Many materials show autofluorescence when exposed to ultra-violet light. Aged natural resin varnishes characteristically fluoresce a greenish colour, and new oil paint remains dark under ultra-violet light, so the placement of new additions on top of old varnish can often be detected using ultra-violet inspection.
Paint cross-section analysis
Sometimes it is possible to remove a small chip of paint from the edge of a painting using a microscalpel. This chip of paint (usually less than ½ mm in diameter) can be embedded in polyester resin and cut through as a cross-section to reveal important information about paint layers, the artist’s technique, and the age of pigments used. These samples can be analysed using optical microscopy in normal light and ultra-violet illumination and imaged up to 100 000x using a scanning electron microscope (SEM). Inorganic pigment analysis can be undertaken using energy dispersive X-ray microanalysis (EDX) through the scanning electron microscope (SEM). Various organic analysis methods including fourier transform infra-red spectroscopy (FTIR) are also available.
Text by Anne Carter, Acting Head of Conservation, Queensland Art Gallery, 2002
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