You might know that the phrase “cool light” doesn't mean that it's safe to touch the light bulb. But what, exactly, does it mean, and what does it have to do with your home lighting plan? Simply put, lighting has a color temperature, which refers to the amount of white/blue or yellow/red contained in the light.

This temperature is measured in degrees of Kelvin. Unlike Fahrenheit or Celsius, which both go from cold to hot on an ascending scale, Kelvin ascends from warm to cool. This isn't the only thing about it that seems counter-intuitive. The sun, for instance, is the hottest source of light that there is, and yet daylight – sunlight mixed with the color of the sky – registers as cool on the Kelvin scale.

It's important to know the color temperature of your lighting, because it affects how you see your environment. Cool, blue-white lighting, such as daylight or full-spectrum fluorescent, shows the truest colors. It's the best light for displaying artwork, flowers and plants, and for making sure you don't accidentally pair navy blue socks with black trousers. It's terrible for displaying people, however, due to its tendency to sallow out skin tone and highlight flaws. Warmer lights containing more yellows and ambers, such as incandescents, are far more flattering, which makes them ideal for rooms that will be used for entertaining.

So what happens if you want to entertain in the same room as your art collection? Fortunately, there is a spectrum in between cool white and warm yellow, somewhere along which lies a compromise that will cast both your guests and your paintings in a good light. Below is a list of common light sources and their place on the Kelvin scale. Remember, the higher the degrees of Kelvin, or “K”, the cooler and whiter the light.

• Candlelight – 1,000 K
• Standard household light bulbs – 2,800 K
• Halogen – 3,000 K
• Color-corrected fluorescent – 3,500 – 4,100 K
• Full-spectrum fluorescent – 5,000 K
• Daylight – 6,250 KWhat about the alternative light bulbs such as CFL, LED and Xenon that we've discussed here? Thanks to color-correcting filters, they come in both warm and cool colors. When selecting them, check the package for the number of Kelvins and compare that to the list above to see what type of light it will produce. If the Kelvins aren't listed, then a good rule of thumb is to remember that “warm white” on the label generally refers to the type of light a standard household light bulb produces, while “cool white” will produce something closer to natural daylight.