Understanding the RGB Color Model

RGB stands for "red, green, blue"

Red green blue RGB in paint buckets

Daniele Carotenuto Photography / Getty Images

Graphic designers use various models to measure and describe color, depending on the medium. Those who design for viewing on screens such as computers and televisions rely on RGB (red, green, blue).

RGB Color Model Basics

The RGB color model is based on the theory that all visible colors can be created using red, green, and blue. These colors are known as primary additives because, when combined in equal amounts, they produce white. When two or three of them are combined in different amounts, other colors are produced.

For example, combining red and green in equal amounts creates yellow; green and blue create cyan; and red and blue create magenta. These particular formulae create the CMYK (cyan, magenta, yellow, black) colors used in printing.

Changing the amount of red, green, and blue, you can produce a nearly endless array of colors. When one of these primary additive colors is not present, you get black.

Hexadecimal Triplets for RGB Colors
Jacci Howard Bear

An RGB color is expressed as a series of three numbers known as a hexadecimal triplet; each number corresponds to a red, green, or blue value in that order, ranging from 0 to 255. For example, rgb(255,255,255) produces white.

RGB Color in Graphic Design

The screen you're reading this very article on is using additive colors to display images and text designed in the RGB model. That's why your monitor allows you to adjust only the red, green, and blue colors, and your monitor's color calibrator measures screens of these three colors as well.

If, however, you are designing for print, you will use the CMYK color model. When designing a project that will be viewed both on screen and in print, you will need to convert the print copy to CMYK.

As a designer, you likely produce many files for various media, so staying organized is important. To that end, add indicators like "-CMYK" and "-RBG" to your filenames and keep folders tidy. This will make your job much easier when you need to find a specific file for your client.

Types of RGB Color Working Spaces

Within the RGB model are different color spaces known as working spaces. The two most commonly used are sRGB and Adobe RGB. When working in a graphics software program such as Adobe Photoshop or Illustrator, you can choose which setting to work in.

Adobe Photoshop working space selection
  • sRGB: Best when designing websites, apps, and other digital media.
  • Adobe RGB: Contains a larger selection of colors that are not available in the sRGB space, so it's better for print and for photos taken with high-end cameras.

Adobe RGB images can be problematic on a website. The image might look amazing in your software but dull on a web page. Quite often, this affects the oranges and reds the most. To fix this issue, simply convert the image to sRGB in Photoshop and save a copy that is designated for web use.

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