Like direct light photography, low-angled light is a technique widely used by conservators and restorers. It allows to detect and document the nature of the surface of a work.
It reveals the surface texture and deformations of the canvas. It exposes alterations in the paint layer (lifting, flaking, cracking…) and reveals the artist’s technique (brush strokes, impasto…).
A light is placed at an oblique angle to the surface of the work between 5° and 30°. Only one side is illuminated, which creates very strong shadows on all the raised elements. The advantage of this type of light is that it reveals details that are hardly visible in direct light. It can highlight the artist’s technique as well as the alterations of the canvas and the paint layer. Deformations of the support (warping, lack of tension, dents, etc.) are all exposed. Examination under oblique light is therefore a non-invasive technique necessary to understand the nature of the artwork.