Pastel colors are a softer and lighter version of the primary and secondary more vibrant colors. Pastel colors have both a low saturation and a high value or amount of light (luminance).
During the 18th century in France, what is known as the Rococo style or Late Baroque style was made popular. This included using a pastel color palette.
Since pastel colors are softer, they tend to be soothing to the eye and evoke a sense of calm and peacefulness. However, pastel colors can also be playful and romantic.
Solid pastel colors are timeless and can help to bring about a sense of fun, calm, and freshness to any design. Pastel colors have become popular throughout the design industry.