Analogous colors are groups of colors that are adjacent to each other on the color wheel, with one being the dominant color, which tends to be a primary or secondary color, and two on either side complementing, which tend to be tertiary.
The term analogous refers to the having analogy, or corresponding to something in particular. An analogous color scheme creates a rich, monochromatic look. It’s best used with either warm or cool colors, creating a look that has a certain temperature as well as proper color harmony. While this is true, the scheme also lacks contrast and is less vibrant than complementary schemes.
Red yellow and orange are examples of analogous colors.
These color schemes are most often seen in nature. For example, during the fall, you will often see the changing leaves form an analogous sort of color scheme, progressively moving through the color wheel to create a gradient in its natural pattern.
High-key color schemes have a lighter value, having white added to them or water in the case of watercolors. These have a more pastel-like look to them. Having a high-key analogous color scheme can give your piece a stimulating shimmer that pleases the eye, making everything seem the same color at first until approach. The colors are pure and aren’t affected by their complements which grab attention. This was commonly used in impressionism by artists such as Monet, Pissarro, and Degas. Pierre Bonnard has also been noted for using it.