basic color theory

color theory
What is color theory?
Color Theory is a set of principles used to create harmonious color combinations. Color relationships can be visually represented with a color wheel — the color spectrum wrapped onto a circle.The color wheel is a visual representation of color theory:According to color theory, harmonious color combinations use any two colors opposite each other on the color wheel, any three colors equally spaced around the color wheel forming a triangle, or any four colors forming a rectangle (actually, two pairs of colors opposite each other). The harmonious color combinations are called color schemes – sometimes the term 'color harmonies' is also used. Color schemes remain harmonious regardless of the rotation angle.

Monochromatic Color SchemeThe monochromatic color scheme uses variations in lightness and saturation of a single color. This scheme looks clean and elegant. Monochromatic colors go well together, producing a soothing effect. The monochromatic scheme is very easy on the eyes, especially with blue or green hues.

Analogous Color SchemeThe analogous color scheme uses colors that are adjacent to each other on the color wheel. One color is used as a dominant color while others are used to enrich the scheme. The analogous scheme is similar to the monochromatic, but offers more nuances.
Complementary Color SchemeThe complementary color scheme consists of two colors that are opposite each other on the color wheel. This scheme looks best when you place a warm color against a cool color, for example, red versus green-blue. This scheme is intrinsically high-contrast.

Split Complementary Color SchemeThe split complementary scheme is a variation of the standard complementary scheme. It uses a color and the two colors adjacent to its complementary. This provides high contrast without the strong tension of the complementary scheme.

Triadic Color SchemeThe triadic color scheme uses three colors equally spaced around the color wheel. This scheme is popular among artists because it offers strong visual contrast while retaining harmony and color richness. The triadic scheme is not as contrasting as the complementary scheme, but it looks more balanced and harmonious.

Tetradic (Double Complementary) Color SchemeThe tetradic (double complementary) scheme is the most varied because it uses two complementary color pairs. This scheme is hard to harmonize; if all four hues are used in equal amounts, the scheme may look unbalanced, so you should choose a color to be dominant or subdue the colors.

Chroma, intensity, saturation and luminance/value are inter-related terms and have to do with the description of a color.

Chroma: How pure a hue is in relation to gray

Saturation: The degree of purity of a hue.

Intensity: The brightness or dullness of a hue. One may lower the intensity by adding white or black.

Luminance / Value: A measure of the amount of light reflected from a hue. Those hues with a high content of white have a higher luminance or value.

Shade and tint are terms that refer to a variation of a hue.
Shade: A hue produced by the addition of black.
Tint: A hue produced by the addition of white.

Proportion & Intensity
When colors are juxtaposed, our eyes perceive a visual mix. This mix will differ depending on the proportions of allocated areas.
The color with the largest proportional area is the dominant color (the ground).Smaller areas are subdominant colors.

Accent colors are those with a small relative area, but offer a contrast because of a variation in hue, intensity, or saturation (the figure).
Placing small areas of light color on a dark background, or a small area of dark on a light background will create an accent.
If large areas of a light hue are used, the whole area will appear light; conversely, if large areas of dark values are used, the whole area appears dark.Alternating color by intensity rather than proportion will also change the perceived visual mix of color.