Laser cleaning of parchment: structural, thermal and biochemical studies into the effect of wavelength and fluence

• Published in: Applied surface science Vol. 227; no. 1-4; pp. 151 - 163
• Main Authors: Kennedy, Craig J., Vest, Marie, Cooper, Martin, Wess, Tim J.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.04.2004; Elsevier Science
• Subjects: Collagen; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Laser cleaning; Parchment; Physics; SDS-PAGE; Shrinkage temperature; X-ray diffraction; SDS-PAGE; Parchment; 42.62.-b; Collagen; X-ray diffraction; 61.80.Ba; Shrinkage temperature; 79.20.Ds; Laser cleaning; Diffraction pattern; XRD; Electronic density of states; Small angle X ray scattering; Electrophoresis; 79.20.Ds Parchment; Damage; Non contact measurement
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2003.11.057

Laser cleaning of parchment is a novel technique that has the potential to provide contactless, chemical-free cleaning of historically important documents. However, the effect of laser cleaning on the collagenous structure of parchment is still poorly understood, as is the effect of the wavelength or the energy density (fluence level) used to clean parchment. In this study, small angle X-ray scattering (SAXS), shrinkage temperature (Ts) measurements by the micro hot table technique and SDS-polyacrylamide gel electrophoresis (SDS-PAGE) of parchment samples after laser cleaning reveal the effect of cleaning to the structural, thermal and molecular characteristics of parchment, respectively. The effect of cleaning at infrared (1064nm), green (532nm) and ultraviolet (266nm) wavelengths at a range of fluence levels is investigated. SAXS is used to investigate the removal of dirt from parchment. Laser cleaning at IR or green wavelengths appears not to alter the collagen diffraction pattern from SAXS, the shrinkage activity or shrinkage temperature from Ts measurements or the molecular integrity of parchment as shown by SDS-PAGE. However, parchments cleaned at the ultraviolet wavelength display structural damage and a reduction in hydrothermal stability and molecular integrity.