Systems for providing dual resolution control of display panels are provided. The cathode sheet is provided, at its side edges which come into contact with the electrolyte and are vertically aligned in the electrolysis tank, with an edge protector, made of a ceramic material. The solid milling agent is solubilized in the liquid carrier which eliminates the need for separating the solid milling agent from the dispersion. The probe can also be used with a balloon catheter. The decoding and encoding methods and apparatus are extendable to the inclusion of any number of check symbols. The capillary cavity interconnecting the inlet and the holding chamber has, in one side face of the capillary cavity, cavities not generating capillary force and communicating with the atmosphere, and this prevents mixing of air bubbles into the capillary cavity.