CMYK stands for Cyan, Magenta, Yellow, and Key (Black) and is a subtractive color model used in printing. Colors are created by subtracting light absorbed by inks on paper. RGB (Red, Green, Blue) is an additive model used for digital screens where colors are created by adding light. Because of this fundamental difference, colors can shift dramatically between screen and print.

Screens emit light directly, producing vibrant, bright colors (typically in RGB). Print uses physical inks on paper that absorb light, resulting in a narrower color gamut. Additionally, paper type, ink density and printing technology affect final output. This tool helps preview the approximate printed result by simulating typical CMYK output.

The simulation applies a standard color profile adjustment and a paper‑white reflectance factor to approximate typical coated paper output. It is intended for conceptual preview purposes only. For professional color-critical work, use a calibrated monitor and hard-copy proofs from your printer.

You can use the standard formula: R = 255 × (1 - C/100) × (1 - K/100), G = 255 × (1 - M/100) × (1 - K/100), B = 255 × (1 - Y/100) × (1 - K/100). This tool automatically calculates and displays the sRGB equivalent in the Screen panel. Keep in mind that many real-world workflows require soft‑proofing with ICC profiles for accurate conversion.

Each channel ranges from 0% (no ink) to 100% (full ink). Common process color combinations include rich black (C:60, M:40, Y:40, K:100) and vibrant blue (C:100, M:80, Y:0, K:0). Always check your printer's specifications because some combinations may exceed the total ink coverage limit (e.g., 300%).

Calibrate your monitor regularly, work in a well-lit environment, use CMYK proofing profiles in software like Photoshop, and always request a printed test proof from your print provider. This tool gives an early approximation, but final matching requires controlled physical samples.