HISTORICAL PLASTER COMPOSITION DETECTION USING REFLECTANCE SPECTROSCOPY

Abstract

Reflectance spectroscopy is a non-invasive method that is based on the fact that a specific object/material provides various reflectances in different wavelengths across the spectral range. It can provide unique information regarding the material composition of the object of interest and has been used in many fields in recent years. Determining composition of historical plaster is very important when defining its individual components and possibly place of origin or even its age. This information can be a key issue for its future repairs that are desired to be done as similar to the original method as possible. For a precise reflectance spectroscopy material detection, a fine spectral library is needed. Special mathematical methods are used for comparison of measured spectral curve with individual spectral curves stored in the used spectral library. The spectral analysis then shows similarity of the measured curve with the reference ones. This paper introduces results of the new plaster composition spectral library created by Department of Geomatics, Faculty of Civil Engineering, Czech Technical University in Prague within the Czech Ministry of Culture Project (DF13P01OVV002). This spectral library has been tested on two historical plaster samples.

Keywords

• Reflectance spectroscopy
• plaster
• composition detection
• spectral library
• QSdata software