The main purpose of this preliminary work is an attempt to measure the diffuse reflectance of pigment samples into the visible and near infrared region (380-2200 nm) using a non destructive methodology, which is based on grey level measurements through image processing techniques. Diffuse reflectance coefficient values Rsp are also measured on the same pigment samples using a spectrophotometer equiped with an integration sphere and the transfer functions which correlate Rsp with the measured grey level values after suitable correction are determined. Two different digitizing systems are alternatively used in order to test the reliability of the obtained results : a PC-EYE-1100, 64 grey level system and a MATROX-SAMBA, 256 grey level system as well.