CMYK vs RGB: Screen and Print Color Explained

RGB is built for emitted light

RGB describes color with red, green and blue light components. In common 8-bit sRGB workflows, each channel runs from 0 to 255. When all three are 0 the result is black; when all three are at full intensity the result is white.

HEX color notation is another way to encode RGB channel values, so HEX and RGB can represent the same digital screen color.

CMYK is built around process inks

CMYK uses cyan, magenta, yellow and black ink percentages. White usually comes from the paper rather than from a white process ink, so 0% of all four components represents the unprinted substrate in a simplified model.

Real CMYK is device- and profile-dependent. Adobe notes that the exact range of CMYK colors varies with press and printing conditions.

Why colors can shift during conversion

An RGB screen can display colors that a given CMYK print condition cannot reproduce. Color-managed conversion maps those values into the destination print space, which can change saturation or appearance.

That is why Colormapped’s RGB/CMYK calculators are labeled mathematical approximations. They are useful for understanding channel relationships, not for replacing an ICC-profile workflow or printer proof.

Which model should you use?

For web, app and most screen-first work, use an RGB/sRGB workflow. For professional print, follow the printer or publisher’s requested CMYK profile and proofing workflow.

If the same design will appear in both media, keep a controlled source workflow and expect to review the print conversion rather than assuming identical numeric values will produce identical appearance.

Useful tools

Sources and method

• Adobe Photoshop — Understanding color modes — RGB and CMYK color-mode behavior and print/screen workflow context.
• MDN — CSS color values — CSS color models and syntax, including HEX, RGB and HSL.