Each page has an associated color state, and also a spot color associated. The color state can be on or off. By default, all the pages are considered as b/w pages.

The only important difference between the b/w page and a color page, is that only the page marked as a color page, can be printed in separation from Fred4.

Since many newspapers have RIPs capable to separate composite pages, this function makes sense only if you print color separations from Fred4, and you want to prevent users to send b/w pages to separation.

All colors marked as spot such, qualify.

Moreover, you can assign to a page one the three basic process colors (C, M, or Y).

Before you print such page, you may want to test if elements on page (not the black ones) are of the right spot color (use the flag '16384' of the PageTest command).