Light is visible (electromagnetic) radiation capable of producing directly in humans and animals visual sensations, from which vision results. Artificial light sources are mostly electric sources, like industrial floodlights or linear lighting, while the light they produce is basically a non-electric quantity, expressed in terms of photometric quantities and laws.
Visible radiation is assumed to contain electromagnetic waves in the spectrum in a very narrow range, from 380 to 780 nm. This is the range that our eye perceives, but animals can register radiation of different lengths. Understanding the light wavelength spectrum is crucial in comprehending how different organisms perceive their surroundings.
Light radiation is a small part of the electromagnetic spectrum, which includes electromagnetic waves that cause a reaction in the human eye. The quantity indicating which electromagnetic radiation falls within the range of visible light is the wavelength of light. What is meant by this term? The wavelength of light means the distance between the closest points in which the electric or magnetic field is in the same phase of the cycle. The unit in which the wavelength of visible light is expressed is the nanometer [nm].
The wavelength of visible light determines, among other things, how we perceive the color of a given radiation. All colors of visible light have specific wavelength ranges for themselves. The shorter the wavelength, the more the light is concentrated in colder colors, such as blue, while longer wavelengths are responsible for warm colors, such as red and orange. Knowledge of the wavelength of visible light is of great importance in many areas of our everyday lives - from science, through medicine, to technology.
The visible light spectrum is the distribution of wavelengths of light radiation, or those that we are able to recognize with our eyesight. The range of visible light is assumed to be from 380 to 780 nm. This range is received by our eyes, but animals can register radiation of other lengths.
In the spectrum of visible light there are ranges with different wavelengths that the human eye perceives as different colors, e.g .:
- range with a wavelength from 380 nm to 436 nm - violet
- the range with a wavelength from 436 nm to 495 nm - blue
- the range with a wavelength from 495 nm to 566 nm - green
- the range with a wavelength from 566 nm to 589 nm - yellow
- range with a wavelength from 589 nm to 627 nm - orange
- wavelength range from 627 nm to 780 nm - red.
We see best in the middle of the visible spectrum and worst at the ends of the range.