Colors mean different things to different people and this may be why in some professions color choices are not random. They are deliberately chosen because for some services and some professions the color means as much as what the sign says on the door or on the clothing.
- Yellow
Yellow evokes sunshine and warmth and hope, light and energy. It is also, the color most often associated with amusement and also with envy and avarice, wisdom and connection, happiness, glory, harmony and wisdom. (Depending what part of the globe you are from).
Yellow is common on signage; as black lettering on that hue is easiest to see in the semi-darkness of early morning. Think road, door and airport signage. Choosing yellow is deliberate as it attracts attention and is noticed quickly in peripheral vision, faster than any other color. 
- Orange
Orange being vibrant and warm is used to set objects apart from their surroundings. It is also used to draw attention. It is commonly used on construction sites where a safety orange is used to ensure safety of others on the site.
Orange as a high visibility color is a favorite in outdoor advertising.
- Red
Red is one of the most used for an attention-getting color. It evokes great emotion and represents fire. Red also symbolizes the heart and love.
Red used in many fire brigades means that trucks are more conspicuous on the road; day, night or in bad weather.
- Blue
Blue is one of the three primary colors (the other two are red and yellow and can be used to mix “all” other colors). Blue is one of the most calming colors and is associated with the sky and the sea. It is considered to be a “safe” color and signifies intelligence, reassurance, and trust.
Blue has been an important color in art and decoration since ancient times; for jewelry and ornaments, for fine blue and white porcelain, for the adornment of Cathedral windows and African tribal clothing.
- White
It is the color of milk and is a symbol of purity. Neutral, none attention drawing and familiar white represents cleanliness, purity, and spirituality. White in days long gone used symbolize exclusivity (the Romans wore a white toga as a symbol of citizenship). Most associated with perfection white also symbolized chastity, sacrifice and purity.
White is the color many groups around the world often associate with the good. In many religions it is the preferred color for religious garments. In everyday life white is the most common color for wedding dresses, (symbolizing purity and virginity).
- Green
Green is the traditional color of safety and permission; a green light means go ahead. It symbolizes renewal, and fertility. As green is the color most commonly associated with nature, life, health, youth, spring and hope its associations are very positive; commonly associated with health and growth (vegetation) and wealth (money).
Green is the color of environmental movements and many groups in favor of and promoting environmental protection describe themselves as part of the Green movement.
- Brown
Brown represents credibility and stability and is seen widely in nature ( in wood or soil). In everyday life it represents ruggedness and the rustic. And words for the color brown around the world often come from foods; chocolate, tea, coffee etc.
Brown is the most popular color for military uniforms for its low visibility and can symbolize security, maturity and reliability.
- Black
Black is the darkest color and the most common color used for printing books, newspapers and documents, because it has the highest contrast with white paper and is the easiest to read. For the same reason, black text on a white screen is the most common format used on computer screens.
Black can represent power, elegance, and sophistication and black has been the symbolic color of solemnity and authority, and for this reason is still commonly worn by judges and magistrates.
