LIF uses UV photons for material excitation in order to get spontaneous fluorescence emission informing on its structural composition and assessing on modifications by degradation or cleaning. These materials can be organic (binding media, glues, wood, paper, textiles, varnishes) or inorganic (ceramic (clay/mud brick/terracotta/earthenware/stoneware/porcelain), glass, stone, metal and metallurgical By-Products, pigment).

Laser-induced fluorescence (LIF) or laser-stimulated fluorescence (LSF) is a spectroscopic method in which an atom or molecule is excited to a higher energy level by the absorption of laser light followed by spontaneous emission of light.