We have studied the procedures to control the processing unit (Kodak RP X-OMAT Processor M6-N) by means of those procedures, i, e, pH Metry, Potentiometric titration in the direct control of the processing solution continuously, also the sensitometric procdure in the synthetic control. In this study, we have also checked the constancy of the mechanisms and the solutions of the processor. In addition, we made some experiments in order to study the propricty and the reliability of the various methods of control of the processing unit. The results are as follows : 1) We found satisfaction in the capacity of the 90 seconds unit. 2) It is desirable to control the solutions continuously for 6 or 12 months closely after the installation of the processing unit in order to decide the time of the renewal of the solutions and the quantity of the replenishment according to the exposure dose, sizd and number of the Roentgen films dealt with in each institution. 3) The continuons control of the solutions over 12 months is no more necessary because we can estimate the condition of the solution by the close observation of the daily X-ray film density. 4) The emphasis of the continuous control of the processing unit must be laid on the mechanical control and the cleaning of the apparatus so that we make use of the processor according to the rule based on the data of the control obtained right after the installation of the unit.
