Neutralizing paintings with a projector

A painting needs illumination to be visible. If the illumination is provided by, an LCD data projector, different regions of the painting can be illuminated separately Modern projectors have large color gamuts and can provide a wide range of illumination effects. One possible effect is to project a captured digital image of the painting onto the painting; the resulting superposition of like colors intensifies the contrast and saturation of the image. The opposite effect is to project the complement of the image onto the painting to "neutralize" it. When carefully done, with correct registration, the painting fades into a nearly uniform gray. Although a simple idea, in practice it is not trivial to accurately find the complementary color for each part of the painting, even when it is captured by a calibrated digital camera. This research examines the problems of accurately capturing the image, combining the projector gamut with typical paint reflectances, and determining the available range of complementary projector colors and the final lightness of the neutral image. The work was initially inspired by a student's fine art project, wherein computer animation was superimposed on a painting, bringing it to life.