RGB to CMYK

The primary reason is the different color models: screens use additive RGB light while printers use subtractive CMYK inks. Additionally, RGB can reproduce a wider range of colors (gamut) than CMYK, especially bright, saturated hues. Environmental factors like screen calibration, paper type, and printing conditions also contribute to differences.

"Out of gamut" refers to colors that can be displayed in one color model but cannot be accurately reproduced in another. Many bright RGB colors (especially vibrant blues and greens) fall outside the CMYK gamut because printer inks cannot reflect light with the same intensity as a backlit screen. These colors will be converted to the closest possible CMYK equivalent.

Combining full cyan, magenta, and yellow inks produces a muddy brown rather than a true black. Adding a dedicated black ink (K) creates deeper, richer blacks while reducing ink consumption and drying time. The "K" stands for "Key" because black is often the key color in printing plates that aligns the other colors.

This tool provides a good general conversion, but professional printing requires more sophisticated color management. Factors like specific ink formulations, paper types, and printer characteristics affect final color. For critical projects, work with your printer to create custom color profiles or use professional prepress software that accounts for your specific printing conditions.

Total ink coverage (sum of all CMYK values) should generally stay below 300-350% depending on the paper stock. Excessive ink coverage can cause printing issues like slow drying, color bleeding, and paper wrinkling. This is particularly important for dark colors and shadows, where adding more black (K) rather than increasing all colors helps maintain print quality.