The Basics

RGB

RGB is defined as red, green, and blue. These three basic colors make up the visible spectrum of light. Devices that capture and display color use the RGB color model. Computers, televisions, phone screens, all display in RGB color. Cameras and scanners read RGB color.

The RGB color model is what is called an additive color model in which red, green, and blue light are added together in various amounts to create the visible spectrum of color. When all three colors are added together at full strength or intensity, the result is white light. When their intensity of strength is zero, and they are added together, the resulting color is black.

CMYK

CMYK stands for cyan, magenta, yellow, and key (black), however, in virtually all cases “key” is referenced black. CMYK are the colors defined by the printing process. CMYK printing is also known as 4-color process (4CP) or full color. Inks and toner are made up of CMYK.

CMYK printing is more limited in color reproduction because converting RGB color into color that can be printed using CMYK cannot reproduce the entire visible spectrum of light.

Process Colors Versus Spot Colors

Spot colors are premixed colors that are not made up of CMYK. Think of spot colors as a single crayon, pencil, or tube of paint; you don’t have to combine C, M, Y, and K together to get that single spot color. Spot colors can also be metallics and pastels, which cannot be printed using any combination of CMYK colors. Spot colors cannot be printed on a color printer or color copier since the color of the spot ink is a premixed, single ink. They usually are printed at a print shop or with a professional printer using an offset press that specifies that spot color ink.

There are several companies that produce spot color: Pantone (the most popular spot color printing system in the U.S. and Europe), Toyo, DIC ANPA, GCMI, HKS, and RAL. The Pantone Matching System, usually shortened to PMS, is how spot colors are sometimes referred to. PMS 356 refers to the Pantone system and color 356. In the printing world, the term PMS color and spot color is used interchangeably. In order to correctly see the representation of a spot color, you need to have access to a printed color guide. A spot color guide is a printed book or fan deck accurately representing the color on paper, metal, or vinyl.

Since spot colors cannot be printed using the traditional 4-color process, using a spot color in many cases is not feasible. When printing images, CMYK is used because it can most closely represent the visible range of colors.

Why use spot colors?

Spot colors can give a more vibrant color since it is a single ink instead of an ink color created using percentages of CMYK. Single-color printing is less expensive than 4-color printing. If you want to have a business card printed, printing in one or two spot colors is less expensive than printing in 4-color. Some colors are not possible with any CMYK combination of colors. Florescent colors for instance, can only be made as a spot color. Common uses for spot colors are screen printing, business cards, and packaging.