The color temperature of your lighting will affect a room's appearance.
Cool and warm refer to color temperature in light bulbs. Lighting is measured on the Kelvin scale, which is used to rate lighting for photography and in other sciences as well. This scale rates lighting based on the hues of color emitted.
Definition of "Cool"
A cool color rates 4000K or higher and gives off a low-range blue light, like ice.
Definition of "Warm"
Warm colors score around 3000K, emitting an orange or red-toned light.
Effects
The color range of light bulbs will alter the appearance of colors on furnishings and walls.
Guidelines
The lighting industry has developed a guideline to help consumers achieve truer color from their interior lighting. Light bulbs are rated on a scale of 1 to 100, with 100 being closest to "true" (and, therefore, having the least effect on the colors of your furnishings).
Considerations
Depending on the color scheme in your home, you can choose a warmer or cooler light to enhance the decor, rather than a "truer" light to neutralize the effect.
Tags: color temperature, light bulbs