There are many emitted colors because of the colors in the environment ... example in water, there are many emitted colors because the color of the environment is reflected by the use of light, like rainbow... you can see the different colors through the use of prism. also the molecules----> like for example the sky, it is blue at day time because blue scatter more than red, opposite to that is when sunset, and sunrise,

----> there are only three main colors that we can see the blue, red and green but the cones in are eyes is respond rather broadly by the light comes in, so that red will stimulate to the green, the red to the blue, like mixing, so we see, many colors...