CCT Lighting: Understanding the Basics

What is Correlated Color Temperature (CCT)?

Correlated color temperature (CCT) indicates the hue and tone of white emitted from a bulb or fixture. CCT values are broken into four categories: ultra warm white, warm white, natural white, and cool white. Unless a fixture emits an RGB color, the product will have the CCT labeled. Choosing the wrong CCT can create the wrong tone for your environment. Use the information below to ensure you have the information you need to begin shopping. 

What Do the Different Kelvin (K) Values Mean?

CCT is measured in Kelvin (K); different temperatures on the Kelvin scale represent different shades of white. The higher the Kelvin value, the less yellow and more ‘blue-toned’ a light becomes. We provide the associated Kelvin ranges with the CCT categories below. 

• Ultra Warm White or Warm White Lights will have an orange/yellow glow and a CCT range of 2000K-3500K.

• Natural White Lights emit a shade of light similar to daylight, with CCTs of 4000K-4500K.

• Cool White Lights emit an intense bluish tint and have CCTs of 5000K-6500K. 

Applications 

How Can CCT Affect Mood or Atmosphere?

The CCT used for a space can impact the way a room feels. Having a cool CCT in a bedroom or living room can make it difficult to relax due to the intensity of the blue-toned light. Similarly, having a warm CCT in an office can make people feel tired or unproductive. 

Some areas, such as schools or retail stores, may require different CCTs in different areas. Schools may use a cool or natural CCT in classrooms and a warm CCT in cafeterias. Retail stores may prefer having a cool CCT around product displays, but a warm CCT would be better for fitting rooms.  

Can Lights With the Same CCT Look Different? 

Lights with the same CCT can appear differently, due to different chromaticities. Chromaticity is the hue and saturation of a color without brightness. Factors that may cause lights with the same CCT to look different include the quality of the light, color rendering index (CRI), or being from different brands. If you’re not able to purchase bulbs or fixtures from the same manufacturer, purchase bulbs based on CCT and test them.                                    

What is the Difference Between CRI and CCT? 

CCT is the shade of white emitted from a light source. CRI (Color Rendering Index) indicates the accuracy of how well a light source depicts an object’s colors. 70-79 are poor CRI ratings, appearing as traditional artificial light. 80-89 are good CRI ratings. 90-94 are high CRI ratings. 95+ are ultra-high CRI ratings.  A 100 rating depicts lights as they appear in natural sunlight. 

What is Selectable and Tunable CCT? 

Selectable and tunable CCTs are flexible lighting options with the ability to change between CCT options. However, these lights differ in their uses. Lights with selectable CCT can switch between various CCT values before installation, using a switch on the back or bottom of a fixture.  Lights with tunable CCT can switch between CCT values after installing the lights, using a remote, smart device, or controller. 

For technical questions, don’t hesitate to call us at 866-590-3533 or by email. Our customer service and technical support teams are available from 8:30 a.m. to 8 p.m. CDT Monday-Thursday and 8:30 a.m. to 4 p.m. CDT on Friday.