CellGuard is an automatic calibration system for HelioKlischographs. The calibration process gets independent from the operator! CellGuard operates precise and fast. Under stable conditions (constant copper quality, intact stylus, standard engraving tolerances) CellGuard requires only 2-3 testcut cycles to calibrate the engraver. CellGuard records target and actual values as well as the camera images. Closer engraving tolerances finally lead to a simplified color matching in the press. The fully automatic testcut sequence with CellGuard for K5 Smart and K500 is unique!