What is the main factor determining the complementary color of any given color?

The primary factor determining the complementary color of any given color is its position in the color spectrum. Complementary colors are located directly opposite each other on the color wheel. This relationship is rooted in the way colors combine and contrast in visual perception. For example, the complementary color of blue is orange, which can be explained by their positions in the spectrum: they are on opposite sides, meaning they create a sharp contrast when viewed together.

This principle is essential in color theory and is widely applied in various fields such as art, graphic design, and lighting. Color brightness, opacity, and temperature, while important in their own contexts, do not fundamentally dictate which colors are considered complementary, as this relationship is strictly based on the spectrum positioning. Understanding this positioning helps artists and designers create visually appealing compositions that utilize contrast effectively.