When we talk about colors like green, red, and yellow, it’s important to know what color model we’re using. In the additive color model, which is used for light, colors are created by mixing different wavelengths of light together.
Green and red are actually two primary colors in the additive model. When you mix green light and red light, they combine to create yellow light. This happens because of the way our eyes perceive light and color. The cones in our eyes respond to different wavelengths corresponding to different colors, and the combination of red and green wavelengths is interpreted by our brain as yellow.
On the other hand, in the subtractive color model, which is used for paints and pigments, mixing colors works differently. Here, mixing green (which is made from blue and yellow pigments) and red (which is made from red pigments) can give you a muddy brown rather than yellow. This is because with subtractive colors, you’re essentially removing wavelengths from the light reflected off the surface, not adding them.
So, the answer to how green and red make yellow is that it depends on whether you’re dealing with light or pigments. In the context of light (like in screens and stage lighting), mixing green and red gives you yellow.