Sometimes a video camera recording may not have captured the correct colours of the scene, and can sometimes be caused by having an incorrect 'white balance' setting for the lighting conditions of the situation being filmed. The answer to this problem is mainly 'colour correction' and is achieved with software usually built into the digital editing system being used for the post-poroduction of the video/film. Essentially the colour balance between red, green, and blue (the primary colours of digital imagery) is adjusted a bit like an audio frequency equaliser fornd on hi-fis. The amounts of the colours present are adjusted to match the colours seen by eye on the day (it is a bit of guesswork sometimes). The hue of the general colour balance can also be adjusted, along with the brightness and contrast, and other more subtle changes. Sometimes the video pictures require 'grading' which is essentially using colour correction and other techniques to deliberately give the video/film a distinctive 'look', often used in music videos and films.