Complementary colors are pairs of colors that, when combined, cancel each other out, producing a grayscale color like white or black. They are located opposite each other on the color wheel. For example, red is complementary to green, and blue is complementary to orange. When used together in art or design, these colors create a vibrant contrast that can make each color appear more intense. In practical applications, complementary colors are often used in painting, graphic design, and interior decorating to create visual interest. By pairing complementary colors, artists and designers can draw attention to specific elements and create a balanced composition that is pleasing to the eye.