Color theories have abounded since the time of the Greek philosophers.  Whether through the use of adjectives (cool, warm, soothing, exciting),  metaphor (green with envy) or similes  (green as grass) different parts of the spectrum have been awarded a range of emotional and descriptive attributes.

Red stimulates the appetites and inspires confidence.  Yellow, another warm color, is optimistic and encouraging–think sunny dispositions…  I, myself am partial to greens, but blues have a universally accepted appeal as the face of calm. After watching this incredible time lapse project, I have to agree.