Color theory begins with the color wheel, which shows primary colors of red, yellow and blue that can be mixed to create secondary colors of green, orange and violet. Tertiary colors are made by mixing primary and secondary colors. Understanding color combinations, tints and shades derived from the color wheel allows for effective use of color in design work. Warm colors like red, orange and yellow convey warmth while cool colors such as blue, purple and green imply calmness. Color meanings and their psychological impacts must also be considered when making design choices. Mastering color theory is essential for designers to skillfully use color.