Color matching in design is a critical aspect of creating visually appealing compositions. It involves understanding color theory, which includes the primary colors (red, blue, and yellow), secondary colors (orange, green, and purple), and tertiary colors (mix of primary and secondary colors). Designers use color harmony principles such as complementary, analogous, and triadic to create pleasing color schemes. Color psychology also plays a role, as different colors can evoke specific emotions and reactions.