The visual feedback of the system is created by a Canon EOS 5D Mark II SLR with a 21MPixel sensor and a fixed 50 mm lens. This provides us with a resolution of about 1 mm on the canvas. Two specialized fluorescent tubes with polarization filters are used to illuminate the canvas, also the SLR is equipped with a polarization filter. Selecting the polarization direction perpendicular to the canvas avoids specular highlights of the paint color.