For producing paintings, a number of practical constraints have to be taken into account. Colors react differently to overdrawing when they are still wet. To let them dry we avoid painting on the same place within a given time interval. Colors such as inks are filled into specialized brush pens that allow the robot to draw continuously without dipping the brush into an ink container. For others, such as oil color, only short strokes can be realized after dipping. These characteristics are stored by the robot server in brush and paint color profiles.