People naturally gravitate to either warm or cool colors. Reds and yellows are generally thought of as warm colors and blues and greens are thought of as cool colors. However, you can have a cool red and a warm green depending on the undertone of the color.What in the world am I talking about? We all know that color is made up of a combination of primary colors (red, yellow, blue) or a combination of the combinations of color. Take the color red, generally thought of as a warm color. If you have a warm red the undertone will be yellow. If you have a cool red the undertone will be blue. The same is true when you are talking about greens (generally thought of as a cool color). If you have a cool green the undertone will be blue and if you have a warm green the undertone will be yellow.