Solid background

[GeorgeG]

I  have a project that I am printing to transparent adhesive stickers. My text and images are various solid opaque colors as desired. The rest of the image background has been transparent so the color of the surface that I am applying the stickers too shows through. Now I need a version where there is a solid off white background color in the bottom most layer so that the underlying object color is completely obscured. So far all I can produce is a translucent background color. 

I need some guidance.

Thanks,

George