On the use of photobleaching to reduce fluorescence
background in Raman spectroscopy to improve the
reliability of pigment identification on painted textiles
On the use of photobleaching to reduce fluorescence
background in Raman spectroscopy to improve the
reliability of pigment identification on painted textiles
Subjecting a specimen of red lead watercolour paint on silk to photobleaching was demonstrated to be a simple means by which to engineer a reduction in the magnitude of the fluorescent background that was approximately exponential with time, with a corresponding improvement in the signal to noise ratio of the Raman spectrum, thus rendering the characteristic peaks more easily visible and allowing more confident identification of the pigment. However, relative heights of the Raman peaks obtained from the sample were seen to alter progressively as a result of irradiation, indicating that some component of the sample was undergoing degradation that may result in longer-term damage to a fragile historic artefact. It was also shown that crystals of the lead monoxide pigment massicot were present in the samples ofred lead on a painted silk artefact dating from 1750. It is concluded that this was either due to deliberate mixing of pigments by the artist, contrary to historic records, or as a result of the roasting techniques used to create red lead pigments at the time and not due to thermal degradation of the pigment during Raman analysis.
pigments, photobleaching, degradation, painted textiles
830-835
Macdonald, A.M.
9d55213c-ca93-44e1-a3ae-6e3eccf1e023
Wyeth, P.
cc2fbe44-9585-4f9e-b3f4-477d0a2a96cb
August 2006
Macdonald, A.M.
9d55213c-ca93-44e1-a3ae-6e3eccf1e023
Wyeth, P.
cc2fbe44-9585-4f9e-b3f4-477d0a2a96cb
Macdonald, A.M. and Wyeth, P.
(2006)
On the use of photobleaching to reduce fluorescence
background in Raman spectroscopy to improve the
reliability of pigment identification on painted textiles.
Journal of Raman Spectroscopy, 37 (8), .
(doi:10.1002/jrs.1510).
Abstract
Subjecting a specimen of red lead watercolour paint on silk to photobleaching was demonstrated to be a simple means by which to engineer a reduction in the magnitude of the fluorescent background that was approximately exponential with time, with a corresponding improvement in the signal to noise ratio of the Raman spectrum, thus rendering the characteristic peaks more easily visible and allowing more confident identification of the pigment. However, relative heights of the Raman peaks obtained from the sample were seen to alter progressively as a result of irradiation, indicating that some component of the sample was undergoing degradation that may result in longer-term damage to a fragile historic artefact. It was also shown that crystals of the lead monoxide pigment massicot were present in the samples ofred lead on a painted silk artefact dating from 1750. It is concluded that this was either due to deliberate mixing of pigments by the artist, contrary to historic records, or as a result of the roasting techniques used to create red lead pigments at the time and not due to thermal degradation of the pigment during Raman analysis.
Text
proofs_jrs1510.pdf
- Author's Original
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Published date: August 2006
Keywords:
pigments, photobleaching, degradation, painted textiles
Identifiers
Local EPrints ID: 41261
URI: http://eprints.soton.ac.uk/id/eprint/41261
ISSN: 0377-0486
PURE UUID: 88bf4f8c-3076-4138-b209-b9ac7a73a571
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Date deposited: 14 Aug 2006
Last modified: 15 Mar 2024 08:26
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Author:
A.M. Macdonald
Author:
P. Wyeth
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