This paper proposes a new way to achieve robotic tasks by 2D visual servoing. Indeed, instead of using classical geometric features such as points, straight lines, pose or a homography, as is usually done, the luminance of all pixels in the image is here considered. The main advantage of this new approach is that it does not require any tracking or matching process. The key point of our approach relies on the analytic computation of the interaction matrix. This computation is based either on a temporal luminance constancy hypothesis or on a reflection model so that complex illumination changes can be considered. Experimental results on positioning and tracking tasks validate the proposed approach and show its robustness to approximated depths, low textured objects, partial occlusions and specular scenes. They also showed that luminance leads to lower positioning errors than a classical visual servoing based on 2D geometric visual features.