We don't currently have the ability to print metallics, foils, or white inks on our boxes.
We use digital printing processes, so all of the color is created using CMYK (Cyan, Magenta, Yellow, and blacK) inks. We cannot print in white or metallic inks. If you have areas in your design that are "white," those are areas that will not be printed. So the color of the box material you've chosen (Kraft brown or white) will show through to create the design effect in those places.
However, it's something we are considering for the future, so stay tuned to our product offerings to be among the first to know when it's available! :D
November 1st - December 31st, 2018 we are offering White Ink on our Kraft material as a special option for no additional cost! Not sure how to set this up? Search "White Ink" in our support portal for a list of helpful solutions, or click on our Chat bubble in the lower right corner for immediate assistance :)