The human eye can distinguish approx. 128 different hues, and about 130 different tints. It is most sensitive to green, then red, then blue.
Red tends to be more confrontational, since it is focused in front of the retina. Blue is focused behind the retina, having a more subdued effect.
This may explain why red is used more in retail, and why blue is often used by corporations.
Colors have varying symbolic meanings and psychological effects around the world. The following is a general guide for Western cultures:
Red: Happiness, impulsiveness, optimism, strength, passion, intensity
Gold: Wealth, enlightenment, warmth
Orange: Communication, ambition, richness, expansiveness, generosity
Yellow: Cheeriness, enlightenment, action, intelligence, youth
Green: fertility, life, hope, prosperty, stability, security
Blue: Spirituality, conservatism, rationality, passivism, tranquility
Violet: Royality, loyality, power, wealth, truth, religion
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Dust fills my eyes / Clouds roll by / and I roll with them / Centuries cry / Orders fly / and I fall again
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