The tools we use to describe color are different when the color is printed than from when it is projected.
Projected color is additive.
Printed color is subtractive. In 1666 Sir Isaac Newton used a glass prism to refract white light at different angles according to wave length. He saw a rainbow of colors, which he passed through a second prism to re-form white light. He concluded that white light is a mixture of all the colors of the visible spectrum. Sir Newton was playing with additive color.