Subtractive Color Mixer (CMY, Hex Output)

School taught you that blue and yellow make green. In a printer the blue became cyan, the red became magenta, and the arithmetic changed shape. Ink and pigment do not add light, they remove it: each layer absorbs part of the spectrum and returns whatever survives. This page applies that reasoning to two colors you pick and shows the hex value of what would be left.

The calculation takes the lowest value of each RGB channel, which is the same as keeping the highest value of each CMY component, since cyan is red's complement. Yellow ffff00 with cyan 00ffff yields 00ff00, green, exactly as on paper. The catch shows up with screen primaries: yellow ffff00 with blue 0000ff returns 000000, black, because RGB blue has no red or green left to survive. A real tube of blue paint would give you green.

Feed it colors near cyan, magenta and yellow and it behaves the way paint intuition expects. Feed it two saturated monitor primaries and the result collapses to black, faithful to the model but not to watercolor. Predicting an actual printed color would take an ICC profile and a scattering model such as Kubelka-Munk, neither of which lives here. Inputs are native color pickers, with no ratio control and no swatch of the result, and the math runs in your browser.