Inexpensive, Near-Infrared Imaging of Artwork Using a Night-Vision Webcam for Chemistry-of-Art Courses.

Imaging of artwork is an important aspect of art conservation, technical art history, and art authentication. Many forms of near-infrared (NIR) imaging are used by conservators, archaeologists, forensic scientists, and technical art historians to examine the underdrawings of paintings, to detect damages and restorations, to enhance faded or overpainted inscriptions, to study artists' techniques, to examine questioned documents, and as a nondestructive analytical tool for identifying certain pigments. The spectroscopic principles underlying the NIR imaging of artwork offer a powerful and engaging teaching opportunity for educators offering a chemistry-of-art course. This article introduces an inexpensive imaging system based on a night-vision webcam. The low cost of the total system (less than $20) could allow every student in a science course to use a NIR imaging camera. Examples are given to show the many techniques of NIR imaging that are important in the fields of art conservation and technical art history. Furthermore, additional spectroscopic experiments exploring the diffuse reflection spectra of traditional pigments in the visible and NIR regions are recommended to help explain the numerous interaction phenomena responsible for the NIR images of artwork and other objects and the occasionally bewildering images acquired outside the familiar visible spectrum.