VIS-NIR Reflectance Spectroscopy is a non-invasive technique that employs optical fibres to measure the reflectance of light from a surface. It is a valuable method for identifying pigments, colourants, and their changes. The technique works by shining light onto an object and analysing the light that is reflected back from the surface. The reflectance spectra display the intensity of radiation reflected from the surface under examination, plotted on the vertical axis as a function of the wavelength of the incident radiation. The intensity value, expressed as the percentage of light diffusely reflected by the surface, is compared to a reference white, assumed to reflect about 100% . The identification of the materials present is achieved by comparing the reflectance spectra obtained from the artwork with those derived from reference paint layers.

Uv-vis-nir reflectance spectroscopy

Analysis Method

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