“Colours change our emotions. . . . Room colours alter moods and can be adjusted using projection: coloured glass or plastic, or coloured light bulbs or overhead transparencies or electronic software. Red stimulates blood and is good for activity areas. Violet is good for sleep, calms the body and balances the mind. Blue lowers blood pressure and reduces stress, whereas green balances the body and is a spirit colour.”

—Colin Beard & John P. Wilson, Experiential Learning: A Best Practice Handbook for Educators and Trainers, second edition, 2006.