Psychology of Colors
Colors on their own create a feeling for each viewer as each color has it's own personality. Of course, when personal preference, cultural backgrounds and experiences come to play, the colors on their own may not have the specific meaning intended. However, even if each color may not affect the feelings of another person as intended to doesn't mean that colors don't have their own personality that describe themselves.

Here are some popular words that describe each colors personality.
Purple - Creative, wise
Green - Growth, health
Blue - Boldness, intelligence
Yellow - Optimism, warmth.
Red - Excitement, youthfulness
Gray - Balance, calm
Orange - Friendliness, fun
These personality words change with each context that the color is placed in. Colors are mainly used to enhance the feeling of the art you're trying to create... they are on their own do not accurate tell the whole story. So let yourself play with different colors and see how they play into the picture you end up drawing. Think outside the box, and let each color on paper be a building block to your whole piece of art.