Some results of the photometry of plates which were digitized with the Microtek ScanMaker 9800XL TMA scanner are presented. Data processing was performed with MIDAS/ROMAFOT. For plates with two expositions, the method of the characteristic curve linearization, for each exposition individually, was proposed and realized. The steps of the processing of digitized plates with automatic exception of the photometric equation of field are shown. It is considered how the precision of astrometric and photometric measurements of plates depends on the stellar magnitude.