Scientists, artists and some of the world’s biggest companies are carving up the visual spectrum, and claiming certain colours as their own, so who does have a right to use the colours of the rainbow? We explore the ongoing rift over the worlds “blackest black” Vantablack, which was created by engineering firm Surrey Nanosystems, and can only be used by the artist Anish Kapoor. Contemporary British artist Stuart Semple argues that creativity should not be limited by commercial agreements, while Surrey Nanosystems executive Ben Jensen explains that the material is not suitable for general use. Author Kassia St Clair explores the meaning and history of colour, and we hear how interpretations of colour have changed from Julie Irish, an assistant professor specialising in colour, at the College of Design in Iowa. Note: Surrey NanoSystems has clarified their material Vantablack isn’t toxic, as described by one speaker in this programme, but can be an irritant.(Picture of a colour splash via Getty Images).