Cross Colouration

    Cross colouration is the presence of false colour in an image. This only affects video that has been processed in composite format rather than being processed in component format. For further details on how this artefact comes about, see my Video Connectors article. Areas of closely spaced lines in the image take on false colours between the lines, typically a purple discolouration. White shirts with fine dark stripes are particularly prone to showing this artefact. Black and white movies that have been processed at some stage in composite format are also prone to showing this artefact, as a purple discolouration around fine lines.
 

Eric Clapton: Unplugged 2:06

Close up of Eric Clapton's collar - note the finely spaced black lines on his shirt and collar and the resultant false colours on his collar in the image.