Colour brightness & light intensity

About colour brightness & light intensity
  • The perception of colour depends on the wavelengths that reach an observer’s eyes. Red has a longer wavelength, while violet has a shorter wavelength.
  • Any colour (e.g. red, magenta, or violet) can be defined by its hue, saturation, and brightness.
  • Saturated colours are produced by a single wavelength of light or a narrow band of wavelengths.
  • The brightness of a colour depends on the intensity of the light emitted by a light source (e.g., a coloured light bulb) and the amount of light reflected from a coloured surface.
    • So, for example, the texture of a surface can affect brightness even when the intensity of the light source remains constant.
  • The intensity of light, along with factors such as phase and interference, are directly related to the amplitude of an electromagnetic wave.
  • Amplitude measures the height of light waves from the centre-line of a waveform to its crest or to a corresponding trough.
  • Colour brightness, light intensity, and the amplitude of a light wave can all be thought of in terms of the number of photons that strike the eye of an observer.
    • Therefore, increasing the amplitude of a wavelength of light will increase the number of photons falling on an object, making it appear brighter to an observer.