A few years ago, I started to print separate layers of colors for decals. This is for a couple of reasons. Foremost, it allows for much crisper graphics. And from an artwork standpoint, layering does not require the tedious task of trapping lighter colors under the next darker. Commercial screen printed graphics, are constrained to .004, or four one thousands of an inch. If the outline of your lettering or graphic is below that, it just wont print. However, if you make the outline a solid object, and then the next color over it, you can obtain those very fine outlines. By layering, I can get graphics that are otherwise not possible to print as one. There are a few drawbacks. One being, you have to let each layer dry completely. And layering is more time consuming. However, I am never in a hurry, and prefer the results of layering, especially on a model I just took weeks to build. Layering is probably not for the beginner, but you can get the hang of it pretty quickly. Another thing that layering requires, is careful study of the vehicle, and how the graphics are actually done. I will provide to very different examples below.