We see yellow light when red and green light enter the eye from the same source. This is known as additive color mixing.
Understanding Additive Color Mixing
Additive color mixing is a process where different colored lights combine to create new colors. Unlike subtractive color mixing (like mixing paints), where combining colors results in darker shades, additive mixing results in brighter colors. When red and green light are combined, they stimulate specific receptors in our eyes, resulting in the perception of yellow.
- Red light: Stimulates a specific set of cone cells in the retina.
- Green light: Stimulates a different set of cone cells.
- Red + Green light: Stimulates both sets of cone cells simultaneously, leading to the perception of yellow. The brain interprets this dual stimulation as the color yellow.
The provided text explicitly states: "For example: red light looks red and green light looks green, but when red and green light come into your eye from the same source — well, then it looks like yellow light. (This is called additive color.)"
Beyond Red and Green
While red and green light combining is a common example, it's important to note that yellow light can also be perceived through other means:
- Monochromatic yellow light: A single wavelength of light can also appear yellow to the human eye. This is a pure yellow, different from the one created by additive mixing.
- Other combinations: Though less common, other light combinations might also appear yellow depending on the intensity and wavelengths involved.
This explanation focuses on the physiological aspect of how the human eye and brain interpret light to perceive the color yellow. The other references provided relate to various other uses of the term "yellow light," and are not relevant to the question of how we visually perceive the color yellow.
