A system for controlling the operation of a printing press used to apply an aqueous printable electrically conductive ink onto a substrate to create electrically conductive traces of such ink includes a probe for contacting the electrical traces and for obtaining a resistance measurement therefrom. A computer receives the resistance measurement, compares such measurement with pre-selected data correlating resistance with acceptable performance criteria for such traces, determines whether such resistance measurement signifies acceptable performance, and signals an appropriate mechanism for identifying those electrical traces which do not meet the acceptable performance criteria. Unacceptable traces are removed from the press prior to further processing. The computer can also signal an ink replenishment or conditioning system, contained in a replaceable cartridge, to correct any abnormalities in the ink properties.