Colors are created by a mixture of Cyan, Magenta, Yellow, and Black so this is often called the CMYK process. Printing presses use this system so your campaign images should be in this color scheme. One-color printing should be grayscale or black bitmap.
This is a more expensive method because each color is printed with its own ink, rather than mixtures of colors like the CMYK process. Spot color can be useful for single-color printing or all black, but additional colors can raise costs quickly.
Pantone Matching System (PMS):
This is a popular system used by printers to provide spot colors. Each color has a corresponding PMS number, and it ensures you get the right color on your finished mailing even if it does not appear correct on your computer monitor. PMS is best used for spot color orders.