Quantitative multispectral imaging for the detection of parchment ageing caused by light: A comparison with atr-ftir, gc-ms and tga analyses

In this paper a non-invasive quantitative multispectral imaging technique was used for monitoring the degradation of parchment caused by light exposure. The parchment samples were aged for 24, 48, 72 and 120 hours in a weather-ometer ageing chamber to simulate a long term sunlight exposure. The effect of light exposure when a ultra violet (UV) filter is used was investigated. The degradation was monitored by using Light Emitting Diode (LED) multispectral imaging coupled to multivariate statistical methods and infrared spectroscopy, gas chromatography-mass spectrometry (GC-MS) and thermo-gravimetric analysis (TGA) techniques in order to elucidate the mechanism of the parchment ageing and to correlate chemical and imaging data. A description of the effect of light exposure is given: the degradation of collagenous phase and thermo-oxidative phenomena are not involved in the photo-oxidation process and, as expected, the UV radiation accelerates the ageing effects. Moreover the non-invasive imaging methods used for the detection of ageing and the monitoring of the conservation state of the parchment surface were able to identify the nonvisible degradation long before possible detection by other common analytical techniques.