wavelength:: 620-750 nm
emotion:: anger
the longest visible wavelength. highest energy in the warm spectrum
evolutionary signal: fire, blood, thermal injury, dominance display
properties
highest arousal of any color — accelerates heart rate, increases blood pressure
most visible at distance in natural environments
the color of iron oxide — rust, soil, Mars
in nature
warning coloration (aposematism): toxic frogs, venomous snakes, poisonous berries
ripeness signal: fruits shift from green to red when ready for dispersal
blood: the universal marker of injury and vitality
fire: the oldest human tool and oldest human threat
in prysm
danger, critical failure, system overload, resource depletion
the stop signal — immediate attention required