Scientifically speaking, green is primarily defined by its physical properties as light and its perception by the human eye.
Green in Physics
In the realm of physics, green is defined by a specific range of light wavelengths. This light falls within the visible spectrum, which is the portion of the electromagnetic spectrum that is visible to the human eye.
- Wavelength Range: Green light occupies the wavelength range of 495–570 nanometres.
- Position in Spectrum: This range is located in the middle of the visible spectrum, between blue (shorter wavelengths) and yellow/red (longer wavelengths).
This physical property is why we perceive objects as green when they reflect or emit light predominantly within this wavelength range.
Green in Art and Colour Theory
While physics defines green by wavelength, in art and conventional colour theory, green is understood in terms of how colours mix.
- Colour Wheel Position: On the conventional colour wheel, green is positioned between yellow and blue. It can be created by mixing yellow and blue pigments.
- Complementary Colour: Green's complementary colour on the traditional colour wheel is red. Complementary colours are opposite each other on the wheel and, when combined, can create a neutral colour like gray or brown, or when placed next to each other, they create strong contrast.
Understanding green involves appreciating both its physical nature as light with a specific wavelength and its perceptual and theoretical roles in how we categorize and mix colours.
