Colour gamut refers to the range of colours which can be managed within a content processing chain. It is limited by prevailing technology, for example, camera sensors or display characteristics. Wide Colour Gamut is a term used to describe an extension of the HD colour gamut (BT.709) to include a much wider range of colours that current technology enables, and is defined in BT.2020.
Using WCG with HDR offers content producers a massive array of artistic options to support their storytelling. As long as the end viewer has a suitably enabled display, pictures can now move closer to realism with a richness and depth not previously available outside the cinema. However, such benefits are lost if the content is badly converted. For example, if the content was produced with WCG but an intervening standards converter treated the video as BT.709, viewing on a BT.2020 compliant monitor will be disappointing, as the colours will appear desaturated.