What?
From V6.4.7 a revised interface is available in the RIP allowing greater control over the loaded media for each media source (e.g. Roll 1, Roll 2, Sheet, Tray):

Why?
The changes are part of an improvement which gives the user more control over informing the RIP which media is currently loaded if the printer in question is unable to automatically report that information to the RIP itself. In practical terms this means that printers with multiple roll & auto switch* can have two rolls ‘loaded’ at the same time in the RIP.
In an automated workflow jobs are delivered to the RIP with minimal user intervention. Jobs may be delivered to the RIP that need to be printed on a media that is not currently loaded. These jobs will be held until the user changes the loaded media type:

The above scenario shows jobs with 3 different media types delivered to the RIP. The printer has an auto switch* function allowing for two active medias loaded at the same time. The jobs with the Banner & White Vinyl will be printed, and the PVC will be held until the user changes the loaded roll on the printer and RIP.
How?
By default the media type will stay on ‘Any’, this means all jobs will be sent to the printer. To change this you first need to switch OFF the setting ‘Ignore printer media changes’. You will find this in Output Device settings:

After you have turned this off, the media type selection becomes available:

Now you can edit the media type for each media source
* Auto switch = A printer with more than one roll actively loaded, the printer can automatically switch between the rolls depending on the job it receives.