Convert between CMYK (print) and RGB/Hex (screen) color values with visual swatch comparison.
CMYK Color Converter translates cyan, magenta, yellow, and black percentages into RGB channel values and Hex notation, or converts an RGB or Hex color back to CMYK percentages. It also provides swatches for comparing the entered and converted colors on screen. The important surprise is that this is a numerical conversion, not a print proof. Actual CMYK appearance depends on the color profile, inks, press, and paper, while a browser can display only an RGB approximation.
A concrete input and expected output from the current implementation.
Input
CMYK: 0%, 100%, 100%, 0%
Expected output
RGB: 255, 0, 0; Hex: #FF0000
With no cyan or black, the red channel remains at 255. Full magenta and yellow reduce the green and blue channels to 0, producing pure RGB red.
CMYK channels are percentages: cyan, magenta, yellow, and key (black). For CMYK to RGB, convert each percentage to a fraction, then calculate R = 255 * (1 - C) * (1 - K), G = 255 * (1 - M) * (1 - K), and B = 255 * (1 - Y) * (1 - K). The 8-bit results are rounded.
Hex does not define a separate color model here; it writes the red, green, and blue bytes as two hexadecimal digits each. In the reverse direction, RGB is normalized, K is derived from the largest channel, and C, M, and Y are calculated relative to the remaining range. Pure black is represented with K at 100% and C, M, and Y at 0%.
No. Hex describes an RGB screen color, while printed CMYK depends on a particular output condition. The converted value is useful as a numerical approximation and coordination aid, but reliable matching requires color-managed applications, suitable ICC profiles, a calibrated display, and usually a physical proof from the intended printing process.
CMYK has four channels while RGB has three, so the relationship is not one-to-one. Black ink can replace combinations of cyan, magenta, and yellow without preserving a unique original recipe. Rounding can collapse additional nearby values. Converting back therefore produces a valid calculated CMYK representation, not necessarily the CMYK numbers initially entered.
The example and behavioral notes were checked against the browser implementation. Standards and primary references below define the relevant format, formula, or platform behavior.
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