We're all familiar with temperature and degrees in terms of Celsius (C) and Fahrenheit (F), but not many people are aware of the Kelvin (K) scale. While units of degrees are used to measure Kelvin based color temperature, it is not measured in degrees that you can FEEL (like Celsius/Fahrenheit do with atmospher ic temperatures), but it measures in degrees that you SEE; the Kelvin temperatures typically fall between a range of 1,000K to 10,000K, with lower temperatures resulting in orange and higher temperatures re sulting in blue. Read more on the technical history and variations here.
The Kelvin degree chart is useful for easily isolating various color temperatures and visual outputs, but the three most commonly used color temperature degree ranges and general terms are
This refers commonly incandescent bulbs (and now LED) and are typically in the 2,700K-3,500K color temperature range. Many historical Warm White bulbs are standard filament based incandescents (although CFL and LED have certainly produced acceptable counterparts). Warm White definitely has a more relaxed feel and can even "appear" dimmer than higher/cooler color temperatures.
This refers to bulbs (frequently fluorescent styles) that are in the 4,100K range. This color temperature emits a much more white form of light, but does not venture into the blue range yet. Because it is much less orange than Warm White, it can stimulate more than sedate and is used frequently in offices and warehouses with 4' fluorescent or LED tubes.
This refers to bulbs with temperatures that circle around the 6,000K-6,500K mark (also com monly called "Full Spectrum"). This has received the name "Daylight" due to the tendency for 6,000K-6,500K range to reflect what the color temperature of the sun produces at 12:00 noon on a cloudless day. Because of the sunlight emulation effect, there are many people in north ern climates that love these color temperatures as it can assist in coping with Seasonal Affec tive Disorder.
Color Temperature selection is widely a personal preference; each degree range will make a room feel a particular way, and in turn, will make the person IN the room perceive things differently. Most residential rooms are lit with warmer (orange/low) color temperatures to create a relaxed feel, and most commercial rooms are lit with cooler (blue/high) color temperatures to allow for a more alert environment. One thing is for sure: color temperature selection will dramatically change the way a room or space feels! For assistance in isolating the best color temperature for your room.
