White Ink print jobs require media profiles with a particular ink configuration and spot colors defined.
Arizona Quality-Layered print mode is used to print white ink applications such as under-printing for non-white media, over-printing for backlit applications viewed second surface or as middle layer for a day-night application.
Print modes other than Quality-Layered mode can also be used to print only white ink, or areas of white ink in an image, as long as the ONYX media profile (media model) has been made with a CMYKSS ink configuration with spot colors defined.
NOTE
When printing white ink using print modes other than Quality-Layered, it is not recommended to print white ink in the same area of an image as CMYK inks. The white ink does not mix well with the other ink colors.