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Understanding Color Spaces: RGB vs CMYK vs HEX
A designer's guide to the major color models, when to use each one, and how to convert between them without losing fidelity.
Utilzy TeamApril 18, 20267 min read
RGB: The Language of Screens
RGB stands for Red, Green, and Blue. It is an additive color model where light is emitted from a screen and colors are created by mixing different intensities of these three primary colors. Add full red, green, and blue together and you get white. Remove all light and you get black.
Every digital display — from smartphones to cinema projectors — uses RGB. When you design for the web, mobile apps, or video, RGB is your native color space. Values range from 0 to 255 for each channel, giving approximately 16.7 million possible colors.
CMYK: The World of Print
CMYK stands for Cyan, Magenta, Yellow, and Key (black). It is a subtractive color model used in physical printing. Instead of emitting light, CMYK inks absorb specific wavelengths and reflect others. Mix all four inks at full density and you approach black.
The critical difference is gamut. RGB can produce colors that CMYK inks simply cannot replicate — particularly bright oranges, vivid greens, and deep blues. This means a stunning RGB design may look dull and muddy when printed. Always convert to CMYK and review a proof before sending designs to press.
HEX and Web Design
HEX codes are shorthand for RGB values, written as a six-digit hexadecimal number preceded by a hash. #FF0000 represents full red, #00FF00 full green, and #0000FF full blue.
HEX is the standard for web design because it is compact, copy-paste friendly, and universally supported by browsers and CSS. Modern workflows also increasingly use HSL (Hue, Saturation, Lightness) because it is more intuitive for creating color variations and themes.
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