Space, distance, atmosphere, volume, and curved or rounded forms are some of the visual effects created with gradation.
[1] Artists use a variety of methods to create gradation, depending upon the art medium, and the precise desired effect.
The early decades of the development of photography involved much effort and experimentation aimed at improving gradation detail in photographs.
The invention of halftone photography was an important milestone, allowing photographs to be reproduced for mass publication in newspapers and magazines.
These constraints are eliminated in digital photography, where software can be used to manipulate photograph images to create gradation.