A tone is where an artist adds grey to a colour. Green Apples, Paul Cezanne, c.1872-73, oil on canvas, The Art Archive / Alamy Stock Photo Still Life with Green Apples (Paul Cezanne, 1873 ...

The colour red has many different meanings ... Antiques & Collectables / Alamy Stock Photo In this crime prevention poster (Central Office of Information, 1960s), the bright red suggests danger.