Print white on colored paper

"Printing" is a wide subject. You didn't state what printing method is being used. In order to actually print white, you have to be printing with a method which uses opaque ink. So you have to build your file to suit the printing method you are targeting.

You also need to show or clarify the nature of the artwork. Whether it is line-art or continuous-tone has a large bearing.

Normally, offset lithography prints inks which are translucent. Even inks with some opacity (some spot inks, such as metallics) are printed so thinly that they are still translucent when printed onto colored stock. That's why offset lithography by far usually assumes white paper. When dark "backgrounds" are required, the background itself is printed and the "white" elements are voids, revealing the white paper.

Offset lithography shops often use a separate press run on a letterpress machine for opaque elements on dark substrates. That process supports the use of truly opaque "inks" such as foils.

Screen printing is entirely different. The "norm" for screen printing is opaque inks and translucent inks (for example, for four-color CMYK process) is usually the exception to the rule, and comes with its own set of trade-offs because screen printing is generally lower-resolution than offset lithography.

Flexography can print opaque inks, but is kind of a compromise between offset lithography and screen printing. It can, for example, print opaque inks which are somewhat "thicker" than offset lithography onto dark substrates like plastic bags, but its resolution is still limited for anything that has to be halftone screened.

Some digital composite printers (e.g., large-format plotters as used in the sign trade) support optional opaque ribbons or inks. But those methods are not generally intended for high-volume printing.

So the answer to your question depends highly upon the nature of the project and the target printing method.

JET

The only way that I know to print white from Illustrator onto colored paper is to:

1) Create a 0%K swatch in Illustrator and create elements with it (easier to see against a contrasting color background from your art).

2) When you finish doing the job, be sure to delete the contrasting color background element(s).

3) Make sure you tell your printer you want to print a white color plate, whereupon ...

4) Your printer creates a "white" color separation, loads the press with white ink and applies it.

It can be done, but not without extra effort and expense.

You can print with white using process like silkscreen or an special printer like this: 711WT Digital White Toner Printer

Otherwise is impossible!