Color temperature

Color temperature is a property of light. Color temperature is expressed in Kelvin (K). The higher the Kelvin, the whiter the light. Higher color temperatures appear warmer in color, and lower color temperatures appear cooler in color.

Color temperature should be considered for both aesthetic and practical reasons. In the context of eye care, color temperature should be considered as a means of preventing eye strain.

Preventing eye strain

The color temperature of screens such as television screens or smartphone screens should, if possible, be close to the color temperature of the environment.

If outside, the screen should be changed to match the color temperature of sunlight or other outdoor light sources. If indoors, the home's residents have control over the color temperature of indoor lighting; residents can purchase light bulbs or other lighting equipment with the desired color temperature, and they can change the color temperature of television screens and other screens to match the color temperature of the room.

Color temperatures that are too warm may make it difficult to focus on tasks. So, a neutral or cool color temperature is preferred for working on tasks that require vision.

It may be preferable to choose a warmer color temperature (near 3000K and lower) in rooms that should promote rest, cooler color temperatures in rooms that should promote wakefulness (near 4000K and higher), and neutral color temperatures in rooms that should not influence wakefulness (near 3500K and lower). For simplicity, residents may choose to have the same color temperature in all rooms.

Some screens will need to be manually set to the color temperature that matches the indoor or outdoor environment. Smartphones and personal computers have features that allow them to automatically set to the correct color temperature using sensors that detect the color temperature of the current environment. In that case, simply ensure that the feature is enabled. For assistance finding the appropriate color temperature settings, search the Internet or consult the owner's manual.

Common color temperatures

The color temperature of sunlight changes depending on its position in the sky. At sunrise and sunset, the color temperature of sunlight is 2000K. An hour after sunrise, the color temperature is 3500K. By noon, in the summertime, the color temperature can reach 5500K.

The color temperature of light bulbs does not change significantly unless it is designed to.

Color temperatures commonly found in light bulbs are listed below:

• 2700K – Warm white
• 3000K – Soft white
• 3500K – Neutral white
• 4100K – Cool white
• 5000K – Bright white
• 6500K – Daylight