Multi-spectral fluorescence imaging for cultural heritage

A portable fluorescence multi-spectral imaging system was developed and applied to the analysis of artistic Surfaces. The imaging apparatus exploits UV lamps for excitation and a liquid crystal tunable filter coupled to a low-noise CCD as the image detector. A sequence of images is acquired by sweeping the transmission band of the filter in order to slice the fluorescence emission in many narrow bands within the visible region of the e.m. spectrum. In this way, the fluorescence spectrum is recorded in each point of the analyzed area. The main features of the system will be discussed, together with its application to the analysis of the fluorescence proper-ties of binders and pigment typically used in mural paintings. Finally, the study of the conservation of Renaissance frescoes recently restored will be presented.