Color depends on light because it is made of light.
There must be light for us to see color.
A red shirt will not look red in the dark, where there is no light.
The whiter the light, the more true the colors will be.
A yellow light on a full-color painting will change the appearance of all the colors.
Color in Fine Art
Renoir painted this painting to emphasize the color and richness of the vegetables and fruits of France. It is basically a cool color with warm accents. Renoir was an Impressionist painter who used color to show depth and volume in his paintings.
Source: Elements and Principles of Design: Student Guide with Activities, published by Crystal Productions
Color in Graphic Design
Black Cat Menu
This menu is designed using all warm tones. Warm tones consist of any color on the warm side of the spectrum: yellows, reds, oranges and purples. The effect is great for a menu because it communicates a comfortable feeling and a compatibility with food. Could you imagine this same menu done in cool tones: blues and greens? The effect would be completely different. It is no coincidence that most fast-food restaurants use yellows and reds for their identities. These colors have been shown to be among the most appetizing.
Source: Design Basics for Creative Results by Bryan L. Peterson
You'll find out a whole lot more about color when we get to Color Theory.