We often say or hear that a certain lamp has a nice warm color. But what exactly is the color of light? How is it measured? Here, we give some jargon-free advice how to choose a good light color for a lamp.
The light temperature of an LED lamp (and all other non-incandescent sources of light) is specified by a physical value called ‘Correlated Color Temperature’ (CCT). CCT indicates the appearance of the light produced by a lamp. It is measured by comparing the light of a surveyed lamp with the light of a reference light source heated to the specific temperature. CCT is expressed in Kelvins (K).
In practice, CCT index is used to distinguish between ‘warm’ and ‘cool’ light. Lamps with CCT rating lower than 3200K are considered as warm (more yellow/red), while those with CCT rating over 4000K are considered to have cool (more blue) appearance. Generally, the higher CCT value is, the bluer the light is.
A standard incandescent lamp usually has a warm yellow light of 2700K, while halogen lamps are slightly whiter (3100K). LED lamps give you a wide range of color temperature to choose from (2700 to 6500K and more).
A bulb should have clear information on CCT value on the packaging and it is important to check it when choosing a lamp to best match your needs.
Most people prefer warm light colors, similar to those of a fireplace or candles and this is explained by a long tradition of gathering around a fire throughout the centuries of our human history. Warm or neutral colors are recommended for living spaces, as they create a cozy and intimate atmosphere.
For rooms used for studying and reading cool light seems to be the best. Researchers have found that reading improves in a setting with the light temperature of 5500-6000K. Cool white light is also perfect for tasks requiring accuracy (e.g. food preparation). They also fit well in some professional spaces.
Warehouses usually benefit from white lighting, helping to see objects better.
Color temperature should not be confused with Color Rendering Index (CRI). CRI measures how well a light source renders colors of objects and materials. CRI has been used for over 40 years for comparing light color performance of fluorescent and HID lamps. However, CRI is not recommended to be used for LEDs. A new special metric system is currently developed for LED lights.
Once you chose your favorite light color, you may want to stick to it. You turn to your supplier for a replacement and… you get the lamp within the same CRI range but of different light color!
This may happen as within a CRI range there are several bins of color to choose from. Every time you may get a different bin of color! When you call the supplier they cannot even explain why.
This will never happen if you order LED lights from our site. We have an established process in place where we can duplicate exactly the same color and Kelvin range in order to provide our clients with a consistent product time over time.
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