Optical Coherence Tomography (OCT) is a non-invasive and non-destructive technique which is very interesting for the study of works of art. Based on a Michelson interferometer, our device has been adapted for the recording of information in the visible range. This system allows three-dimensional imaging of painting with a micrometer resolution. 3D imaging of pictorial layers is presented where the pigments embedded in the binder are clearly visible. Further-more, an adapted signal processing gives access to the spectral information issued from pigments. Tests on pigments in powder are presented and show that their spectral responses are different.