this can provide illusion of fast movement it is often used in videos to censor information for security or density​

Blurring can provide the optical illusion of a fast movement. It is often used in videos to hide sensitive or age-inappropriate information, the protection of identities (hence security) or just to provide decency.

Explanation:

Mostly used during animated videos where unlike (real videos) the blur does not occur naturally, the blur is used to make speed believable. Speed invigorates, and highlights intensity. Blurring still images can help to make more realistics motions of speed. An example where lots of blurring is used as prostproduction effects is in Flash.

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