There are two aspects of color that can help you in creating your center of interest: intensity and temperature. The closer a color is to the primary colors of red, yellow and blue, the more intense it is. The more intense or pure a color is, the more it will draw and hold the viewers attention. This principle holds true for both cool and warm colors. Think about an intense, cool blue, like cobalt. It will draw the eye if played against a field of grayed warm colors. Note that the impact of the blue will be lessened if the warm colors arent as gray.
As far as temperature is concerned, warm colors (reds and yellows) attract the eye and project forward, and cool colors (blues and greens) recede in a landscape under the laws of aerial perspective. In a painting in which all the colors have the same intensity, the warmer colors will attract the eye to a higher degree than the surrounding cool colors. How do you make use of this concept? What about placing a red-jacketed figure in a landscape surrounded by large tree masses? The figure will be dominant because of the warm, intense color thats balanced by the grays of the foliage. A rule of thumb is to reserve less intense colors and cooler colors for areas outside the center of interest.