Blue is a primary color and cannot be created by combining other colors. Adding white to blue creates a lighter blue, and adding black to blue creates a darker blue.
Blue, red and yellow are the three primary colors. Primary colors are colors that cannot be created by mixing any other colors together, but primary colors can be mixed together to create other colors, called secondary colors. For instance, mixing yellow and blue together makes green, while mixing red and blue together creates purple. Orange is created by mixing yellow and red. Both primary and secondary colors can be lightened or darkened by adding white or black respectively.