Highlights as Anchor Points in Jan van Eyck’s Inverse Optics

The art of Jan van Eyck is renowned for its capacity to reveal with extreme accuracy the materiality of object surfaces. The interaction of light with the surface of materials results in reflected light that carries to the viewer the information on the quality of the surface material. Apparently Jan van Eyck understands that seeing a visual object has more to do with tracing perceptually what kind of light is falling on the object and where it comes from than with any conceptual identification of the object. Tracing the light back to its source is in vision studies known as inverse optics. In a visual display, the light source is particularly revealed by the highlights which are mirroring that source. In his pictures Jan van Eyck uses these highlights as anchor points to indicate where in the visual scene the highest lightness is to be found. With further understanding of the physics involved, he carefully observes the specific fall off of the intensity of reflected light around highlights to characterize particular materials. His special sensibility for highlights might have originated in his involvement with the production of miniatures in illuminated books where, depending on the locations of light source and viewer and orientation of the illuminated page, gilded segments can drastically change in brightness. We will compare color and luminance distribution properties around highlights in some Eyckian pictures with comparable pictures of contemporaries (Campin, Van der Weyden) with special attention to metals and gold brocade.