In telecommunication, the term noisy white has the following meanings:

1. In facsimile or display systems, such as television, a nonuniformity in the white area of the image, i.e., document or picture, caused by the presence of noise in the received signal.
2. A signal or signal level that is supposed to represent a white area on the object, but has a noise content sufficient to cause the creation of noticeable black spots on the display surface or record medium.

See also: Noisy black

Source: from Federal Standard 1037C