Dynamic range is the difference between the maximum and minimum values at which light, sound, and so on can be perceived (or reproduced). That difference is expressed as a ratio.
For example, in the case of the dynamic range of light, it is expressed as the difference between the brightest part and the darkest part of an image. The dynamic range of the natural world is said to be 1:10,000,000,000 (one to ten billion), and that of the human eye is 1:100 (one to a hundred). These numbers express how many layers the range (namely, the difference between the maximum and minimum values) can be divided into and perceived (or reproduced); accordingly, it is referred to as "resolution."
