What Is Color Temperature? / What is CCT
Correlated color temperature, or CCT, is a measure of the "color" of a light source. It is often expressed in Kelvin (K) units and corresponds to the temperature of an ideal black body that would emit light of a similar "color." For example, candlelight has a low CCT (around 1800K), while sunlight has a high CCT (around 5500-6000K).
You might be wondering why the color of light is important. Well, different colors of light can have different effects on our mood and behavior. For example, blue light is known to boost alertness and productivity. In contrast, yellow light can help to reduce stress and promote relaxation.
CCT is measured in Kelvin (K) on a scale from 1,000 to 10,000.
Color Temperature Scale
The Color Temperature Scale is a way of measuring the color of light. It is measured in Kelvins (K), and it is a scale from red to blue. The lower the Kelvin value, the more red the light is. The higher the Kelvin value, the more blue the light is.
So, a light with a Kelvin value of 2000 would be redder than a light with a Kelvin value of 4000.
Kelvin values are often used when talking about LED lights because LEDs can emit different light colors depending on the temperature of their semiconductor.
The color temperature scale is also used in photography and film. For example, a film that is meant to be seen in theaters is typically shot at a color temperature of 3200K.
Color temperature can be used in many different ways. It can be used to describe the light appearance of a light bulb, or it can be used to describe the color of light in general.
It can also be used to adjust the color of a light source to match the color of another light source. For example, suppose you have a lightbulb with a color temperature of 3000K, and you want it to match the color of light with a color temperature of 4000K. In that case, you can use a color temperature scale to adjust the color of the 3000K lightbulb to match the 4000K light.
To do this, you would need to find the difference between the two colors on the color temperature scale. In this example, the difference would be 1000K.
You can then use this difference to adjust the color of the 3000K light bulb. To make the 3000K light bulb match the 4000K light, you would need to add blue to the 3000K light bulb.
The amount of blue that you would need to add would depend on how much light you are using and how close you want the two colors to match.
How Kelvin is Measured
As was mentioned, Kelvin is measured on a scale from 1,000 to 10,000. The lower the Kelvin value, the warmer the light will appear. The higher the Kelvin value, the cooler and more bluish the light will appear.
The lower the color temperature is, the warmer the light will appear, while a higher color temperature will appear cooler and more bluish.
For example, a traditional incandescent bulb has a color temperature of around 2,700K, which is in the range of "warm white" to "soft white."
Color temperatures can be measured using a colorimeter, which breaks down the different colors that make up white light into their component parts. The colorimeter then assigns each of these colors a value on the Kelvin scale.
Color Temperature Applications
Not all applications require the same color temperature. In fact, some applications may even benefit from different color temperatures within the same space. Here are some general guidelines to help you select the right color temperature for your needs:
- 2700K: This is the standard color temperature for most household applications. It is a warm light that is comfortable for most people.
- 3000K: This is a slightly cooler light that is often used in commercial applications. It can help to create a more energetic atmosphere.
- 3500K: This is a cooler light that is often used in industrial applications. It can help to improve concentration and productivity.
- 4000K: This is a very cool light that is often used in medical applications. It helps to reduce eye fatigue and makes healthcare professionals more productive.
- 5000-5500K: This is the highest color temperature that is commonly used. It is very bright and can be uncomfortable for some people. It is often used in outdoor applications.
Guide To Selecting Color Temperature by Application
| Setting/Application | Correlated Color Temperature |
| Household Applications | |
| Living Room | A warm white light 2200K-3000K is best for the living room since it creates a cozy, inviting atmosphere that helps you relax and unwind. |
| Bedroom | A relaxing and comfortable environment is important in the bedroom. For this reason, warm white light with a color temperature between 2200K-3000K is ideal. |
| Kitchen | A kitchen is a place where we prepare food and spend time with family and friends. This is a space where we want to feel energized and inspired. A color temperature of 3000K-5000K will help achieve this goal. |
| Bathroom | The bathroom is another space where we want to feel relaxed and rejuvenated. A color temperature of 3000K-5000K will help create this atmosphere. |
| Commercial Applications | |
| Office | An office environment is typically a more formal setting where people are working on tasks that require concentration and focus. In this type of environment, it is important to have a color temperature that is not too stimulating, as this can lead to distraction and decreased productivity. A cool white or daylight color temperature (3000K-5500K) is typically best for an office setting. |
| Restaurant | If you want to create a cozy, romantic atmosphere in your restaurant, try using bulbs with a lower color temperature, around 2700K. This will also be a good choice if your restaurant has dark wood floors and furniture, as the warm light will help to create a cohesive look. For a brighter, more energetic space, go for a higher color temperature, around 3500K-4100K. This will make your restaurant feel clean and modern and is a good choice if you have white walls and lots of natural light. |
| Shop | A cool white light (around 6000K) is best for shops. It makes the space seem bright and clean and makes colors pop. However, you may choose warmer CCT as well (2700-4000k), depending on your shop design. |
| Hotels | |
| Lobby | Warm color temperature (2700K – 3000K): The light is close to the natural light at dusk. It creates a warm and inviting atmosphere. |
| Guest Rooms | Color temperatures of around 2200K-2700K are often used in guest rooms, as they provide a warm and inviting feeling. |
| Common areas | Neutral white (3500K – 4500K): The light in the middle of the day. It is bright and energetic without being harsh. |
| Educational Establishments |
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| Classrooms | The color temperature of light in a classroom should be between 3500-4000K to help students stay awake and alert. |
| Dining areas | Dining rooms at schools are often lit by neutral white (2700-3500K) |
