Configure this setting when using separation output.
Cyan, magenta, yellow, and black are output for each plate, so you can check the printing area for each color.
Touch panel - [JOB LIST] - [Hold Job] - [Job Ticket] - [Job Ticket Edit] - [Separation Output]
Touch panel - [JOB LIST] - [Hold Job] - [Page Edit] - [Job Ticket Edit] - [Separation Output]