Additional Resource Links:

• Color Models
• Gamut
• Color Space
• Color Space and Color Gamut
• Pantone (company)
• Pantone Color System
• Kuler Color
• Color Abstraction (color as Data)

Both CMYK and RGB are color mixing modes in graphic design. In short, RGB is best for digital design, the ones you see on your screen and CMYK for commercially printed designwork

In color theory, the gamut of a device or process is that portion of the color space that can be represented, or reproduced. Color gamut is a measure of how large the color range is according to a specific color model (RGB, CMYK, etc.). Generally, the color gamut is specified in the hue–saturation plane, as a system can usually produce colors over a wide intensity range within its color gamut; for a subtractive color system (such as used in printing), the range of intensity available in the system is for the most part meaningless without considering system-specific properties (such as the illumination of the ink). In general, gamut is the range of something compared to its reference range. For example, the RGB color gamut is a smaller subset of the larger spectrum of all visible color and light.

When certain colors cannot be expressed within a particular color model, those colors are said to be out of gamut. For example, while pure red can be expressed in the RGB color space, it cannot be expressed in the CMYK color space; pure red is out of gamut in the CMYK color space.

Adding a certain mapping function between the color model and a certain reference color space results in a definite “footprint” within the reference color space. This “footprint” is known as a gamut, and, in combination with the color model, defines a new color space. For example, Adobe RGB and sRGB are two different absolute color spaces, both based on the RGB model.

A color space is the type and number of colors which originate from the combinations of color components of a color model. We speak of a color space because a color model defines a—mostly three-dimensional —coordinate system by its components, and in its space one point corresponds to one specific color.

In the most generic sense of the definition above, color spaces can be defined without the use of a color model. These spaces, such as Pantone, are in effect a given set of names or numbers which are defined by the existence of a corresponding set of physical color swatches.

So, if you are designing a project to be printed on an Epson printer and want to get the best color possible, do the following:

First, create your design and choose your colors in RGB color space. (RGB can create and display the largest possible gamut.

Second, once you have a final design, change the color mode to CMYK. Pay particular attention to any colors which may have shifted. If the shift is acceptable, then no problem. However, if one or more of your colors has shifted and you are not happy with that shift, simply choose a different color while in CMYK. (Epson prefers that the incoming file be in RGB. The printer will then convert that RGB image to CMYK for printing.)

Finally, after color correcting in CMYK, change back to RGB for the final version that you send to print. Remember these 3 steps are only for digital printing on an Epson printer. If you are designing to print commercially, then your file should stay in CMYK.