Can an artist ever really ‘own’ a colour?

Anish Kapoor has the exclusive rights to paint using Vantablack, the blackest black that has ever existed – but other artists are keen to use itColour is precious. Colour can drive you mad – especially if you are an artist. The colours that artists use can be as expensive as gold – which installationist Richard Wright painted on to a wall in Tate Britain to win the Turner prize - or as lethal as arsenic, which in the Romantic age was used to make the beautiful but deadly Scheel