Light bulb colour is represented by the temperature. This is measured in a unit called a “Kelvin” or “K.” Kelvin itself starts at the lowest temperature possible: absolute zero and proceeds up for there. For example 72° F or 22° C is 295° K. The freezing temperature of water is 273° K.
Bulbs climb in temperature from a yellow glow at 2700K up to warm halogens at 3000K and upwards to bright white fluorescence at 5000K.
Picking The Right Bulb For the Room and The Role
The hue of a bulb closely matches the role it is intended for. An intimate dining room may have the cool yellow colour an Edison bulb. A commercial setting where light is needed for procedures may use a 4000K or 5000K bulb. Lighting does so much to set the mood. On the cool end of the spectrum, it can remind us dusk and campfires. On the high end, it can convey efficiency and order. While the spectrum is broad, our lighting choice stay in the 2400K to 5000K range.
Temperatures and Rooms They Fit
Less than 2000K: gives off a dim glow of light, similar to candlelight; best for low-light areas where ambient illumination is welcomed. Translation: dining room and hang space.
2000K-3000K: gives off a soft white glow, often yellow in appearance: living rooms, dining rooms, bedrooms and outdoor spaces. Translation: a relaxing space.
3100K-4500K: gives off a bright amount of white light: kitchens, offices, work spaces and vanities where task lighting is needed for working with cosmetics and clean spaces.
4600K-6500K: gives off a bright amount of blue-white light, similar to that of daylight; best for display areas and work environments where very bright illumination is needed. Translation: settings where you want to simulate daylight, as well as industrial and factory settings.