Spectrophotometric Scanner for Imaging of Paintings and Other Works of Art

Abstract

A spectrophotometric scanner has been assembled for applications concerning the conservation of paintings and of other works of art with plane surface. Its optical components, that are a lens, a spectrometer and a monochrome matrix CCD digital camera, are arranged in axial configuration.A frame of the camera allows the image acquisition of a strip of the scene collecting the reflectance spectra of its pixels. The full image is saved as ordered collection of the reflectance spectra of subsequent strips.The scanner needs only optical geometrical alignment and the usual wavelength calibration. Evaluation of the fidelity of the color reproduction gives very good results. Measurements of the scanner contrast transfer function (CTF) has been carried out for the estimation of its spatial resolution.