Color is dynamic. We all see it a little differently, because color is the physical response of the eye to light + the mental interpretation of those responses. This makes printing color accurately a bit tricky until one has a basic understanding of color space.
First, all color starts with light. The color of a physical object is the result of projected light reflecting off the object. Your eyes + brain interpret what gets reflected, and the result is the color you see. A red apple, for example, reflects red wavelengths of light and absorbs all others. You see the reflected red wavelengths. As ambient light decreases, colors appear to fade because there is less light and, therefore, less color.