Luminance noise manifests itself in a video picture as light white noise. It may be the result of electronic failure, recording in low-light, worn or poorly coated tape stock, transmission of a video signal over cables that are too long, over-enhancement of the video signal, or dirty record or playback heads. Color video or black and white video can both contain luminance noise.
Can it be fixed?
If the video output has been properly adjusted for playback and there is no cabling or media issues, then the noise is inherent to the source and is not remediable.