New users of InDesign are sometimes confused by the [Paper] swatch— “Is it white? What color is it?”
I explain it as “No ink prints here,” because “knock out” often doesn’t make sense to newbies who know nothing about printing.
But there’s something you might not know about [Paper]— you can change its appearance. Even though the protective brackets around the name imply it’s ineditable (try saying that quickly, and it always comes out as “inedible”), double-click it and you’ll discover that you can concoct a new CMYK, RGB, or Lab color (you can’t shop in Pantone, Toyo, etc.). Festive, huh?
Why is this allowed? If you’re printing on colored stock, you can mimic the outcome on screen, which is kind of cool. Even cooler, when you print to your desktop printer or export to PDF, that color disappears—as it should, since it’s just intended for onscreen preview.
What About White?
You’ll only see White in your swatches if (a) the file was converted from QuarkXPress or (b) someone didn’t understand [Paper] and felt compelled to create a swatch that would knock out or (c) White is a spot color used when printing on colored or foil stock (for example, on a metallic decal).
If the answer is a or b, just delete the White swatch and replace it with [Paper]. If the answer is c, make sure the swatch is defined as a spot color. It would also be helpful to change the name to something like “Spot White” for clarity.
Note: In Illustrator, “white” means the same as InDesign’s [Paper]—”no ink prints here.”