The RGB and CMYK color models are each used for different purposes. The RGB model is an additive model primarily used for digital design, while CMYK is subtractive and used for printing purposes. When comparing these color models, it’s important to realize that these color models weren’t meant to function in the same spaces or for the same uses. What you’re really comparing is colored light versus colored ink, and color display abilities across mediums.
RGB is a color model for digital color systems. RGB stands for red, green, and blue respectively, because different levels of these colors are all we need to create any color on the visible color spectrum.
While many printing systems can now use RGB to achieve fairly accurate printed results, RGB is best used digitally because computer monitors are capable of displaying far more colors than a printing press.
CMYK is a color model most often used in printing. Also known as the “four-color process”, it stands for Cyan, Magenta, Yellow, and Key (or black) and is a subtractive color model, as opposed to an additive color model like RGB. In printing, CMYK reduces the brightness, or reflected light, from a white background. It subtracts the amount of white showing through by working in levels of cyan, magenta, yellow, and key to achieve the desired color.
It’s possible to convert RGB to CMYK using Adobe Creative Suite. However, if you already know whether your design will be digital or printed, go ahead and build it in the most suitable color model. Digital projects (web graphics, emails, online ads) should always be built-in RGB. Print projects (business cards, banners, t-shirts) should be built in CMYK.
If you own a Color Muse, you’ve likely noticed that it puts out RGB–not CMYK–color values for scans and matches. Color Muse doesn’t support CMYK because this color space varies between available standards, and RGB can quickly be converted in Adobe Photoshop.
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