Imaging techniques such as UV-Vis, IR, multi-spectral cameras or X-rays allow to look below the surface of the artwork in order to look at traces related to the manufacturing process or to some important milestones in the conservation history of the object.
They allow to look at high details in the signatures, inventory marks and other inscriptions. Imaging can also help to reveal modeling processes, cast and molding technologies. Finally, imaging may help identify the stages of creation of the painting: under-drawings, repentance, etc.
Optical observation is the first examination to be made. It is the fundamental mean in expertise and the most obvious of visual examinations. Macroscopic examinations (using naked eye) are distinguished from microscopic examinations (using a microscope). Depending on the angle of illumination (microscopically or macroscopically), direct or raking light, can give different types of information.…