This command is listed in the Experiment menu and is used to subtract a voltammogram stored on the hard disk from the active voltammogram (e.g., for background subtraction). The voltammogram to be subtracted is selected from a standard Windows dialog box. The x axis should be the same for both files. For time base experiments such as CPE, files of different length can be subtracted. The data in common will be subtracted and the extra points in the longer file will be truncated.