The system includes a high definition reading device positioned near the paint booth. When the door or window passes through the booth, the reading device generates a digital picture of the workpiece hanging on the frame. The picture is entered in a computer which writes a specific painting programme for the workpiece. This programme is sent to the robot which then paints the workpiece accordingly. By means of its six axes, the robot can carry out any kind of movement. Even movements required in very complicated painting processes are possible. The workpieces to be painted may have different shapes and sizes, as required or desired by the customer. The following maximum sizes apply to the standard versions: 3.000 mm high and 4.000 mm wide. But even bigger pieces can be processed. For this purpose, the reading device is changed and the robot fixed to a sliding device. The supply of paint is projected in a customized way. The robot system can be equipped by either a manual or an automatic paint changing unit.