Part 10 ~Relationship between LED and color temperature~

What is color temperature?

Color temperature is an index that expresses the hue and temperature of light, and is a numerical representation of the color of light emitted by a light source.
Color temperature is expressed in Kelvin (K), and warmth and coldness are perceived by the difference in hue expressed by color temperature.
Generally, colors can be divided into warm colors and cool colors.

Warm colors have a low color temperature (approximately 2,700K to 3,500K) and represent warm, reddish light.
Warm color temperatures are light that gives a sense of warmth and calm, such as at dusk or candlelight.
Warm color temperatures create a relaxing atmosphere and are suitable for locations such as bedrooms, cafes, and hotel lobbies.

On the other hand, cool colors have a high color temperature (approximately 5,000K or higher) and represent cold, bluish light.
It is similar to bright daytime sunlight on a clear day.
It is characterized by its brightness, cleanliness, and awakening effect, giving a clearer and more vibrant impression.
It is suitable for work environments such as offices and operating rooms because it improves concentration and visibility.

The choice of color temperature is an important factor that determines the mood of the lighting environment and has a psychological impact.
By choosing the right color temperature, you can achieve a comfortable lighting environment and create an atmosphere that suits your location and activity.

Relationship between LED lighting and color temperature

Lighting such as fluorescent lights and incandescent lights have different color temperatures depending on the type of lighting, but a major feature of LED lighting is that the color temperature can be adjusted.
Changes in color temperature can greatly change the atmosphere and effect of lighting.
The effect and atmosphere of LED lighting is determined by the choice of color temperature.
By choosing the appropriate color temperature, lighting can have an effect tailored to the purpose and space, creating a comfortable environment.

[Example of environment with low color temperature]

LED lighting with a low color temperature is widely used to create a warm atmosphere.
Below are some specific examples.

・Create a warm atmosphere in the restaurant

You can create a warmer atmosphere by using low-color-temperature LED lighting to illuminate your restaurant's dining area or bar counter.
Warm lighting generally creates a relaxed atmosphere by making food look delicious and creating a relaxing atmosphere for eating and conversation.

・Indirect lighting in living room

Indirect lighting is often used in living rooms and bedrooms using LED lighting with a low color temperature.
For example, by installing it in your bedroom or living room, it will envelope the entire room with soft light and create a cozy atmosphere.

・Lighting for cafes and coffee shops

Warm LED lighting is ideal for creating the atmosphere of a cafe or coffee shop.
Warm-colored lighting above the cafe's counter and tables creates a cozy space and creates a relaxed atmosphere.

・Hotel lobby lighting

Hotel lobby areas often use low color temperature LED lighting to create a welcoming and warm feel.
Soft light combined with a harmonious interior creates a sense of comfort and relaxation for visitors.
These are some specific examples, but low color temperature LED lighting can be used in many locations and situations.
In order to create a warm atmosphere, it is important to arrange the lighting and adjust the brightness.
You can achieve the optimal effect by matching the lighting design and the location where it will be used.

Example of environment with high color temperature

On the other hand, LED lighting with high color temperature is widely used to create a sense of brightness and cleanliness.
Below are some specific examples.

・Office work space
LED lighting with a high color temperature is effective in office work spaces.
For example, using desk lighting or direct lighting installed on the ceiling can help improve productivity by creating a bright and conducive environment.

・Hospital operating rooms and clean rooms

LED lighting with high color temperature is very important in areas such as hospital operating rooms and clean rooms.
Bright, uniform lighting is essential for healthcare workers to work efficiently.
Light with a high color temperature provides visual clarity and emphasizes cleanliness and hygiene.

・Retail store

LED lighting with high color temperature is widely used in retail stores such as convenience stores and supermarkets.
High color temperature light also enhances the freshness and cleanliness of food and products, accurately displaying product color and quality, and providing a user-friendly environment for customers.
Also, fish and green vegetables look fresher with a high color temperature, but lower color temperatures are said to be more suitable for meat, bread, etc.

・School and university classrooms

In classrooms at schools and universities, we aim to increase the vibrancy of classes and learning by using LED lighting with a high color temperature.
Bright and clean light is expected to promote students' concentration and attention, improving the learning environment.
These are just a few specific examples, but high color temperature LED lighting is widely used in places where brightness and cleanliness are important.
It is important to pay attention to lighting placement and adjusting the brightness of the light to achieve the best effect.

Advantages of LEDs with a color temperature close to sunlight

・Visual comfort

LED lighting, with a color temperature close to that of sunlight, is pleasant to the human eye.
Sunlight has a spectrum that is most suitable for our visual system and provides visual comfort due to its high color reproduction.

・Color accuracy

Sunlight is the light source that most accurately represents the color appearance of objects.
LED lighting with a color temperature close to sunlight can more accurately reproduce the colors of objects.
This is often used in exhibitions, showrooms, and other places where color reproduction is important.
Also, in commercial environments where product design and color are important, lighting that approximates sunlight can help convey accurate information to people.

・Psychological impact

Sunlight also affects our psychological state.
LED lighting, with a color temperature close to that of sunlight, provides brightness and warmth, creating a feeling of comfort and vitality.
Particularly in living spaces and office environments, sunlight-like lighting can provide comfort and relaxation, improving quality of life.

・Reproduction of natural environment

LED lighting, with a color temperature close to that of sunlight, is effective in recreating natural environments in indoor spaces.
Particularly in urban areas or inside buildings, there may be a lack of sunlight, but by using lighting with a color temperature close to that of sunlight, it is possible to reproduce natural brightness and color.
This allows you to feel a natural atmosphere even indoors, providing comfort and refreshing effects.

・Visual three-dimensional effect

LED lighting, which has a color temperature close to that of sunlight, has a clear contrast between brightness and shadow, making objects and spaces appear more three-dimensional.
This helps enhance exhibits in exhibition halls, showcases, etc.
It is also effective in highlighting architectural and interior design elements.

・Compensation for lack of sunlight

In modern life, we often spend a lot of time indoors, and the lack of sunlight can have negative effects on our health, including a lack of vitamin D and serotonin.
Particularly in higher latitudes where sunlight is severely reduced by season and climate, it is beneficial to use near-sunlight lighting to compensate for the lack of sunlight.
LED lighting with a color temperature close to sunlight has a variety of benefits, including visual comfort, color accuracy, psychological impact, sleep regulation, natural environment reproduction, visual three-dimensionality, and complementing the lack of natural light. provide benefits.
These benefits allow people to have a more comfortable and natural experience in indoor environments.

~summary~

Light and color temperature are closely related and have a great impact on the effect and atmosphere of artificial lighting.
The color temperature selection should be made according to the intended use of the lighting and the environment.
For example, in relaxing areas such as the living room or bedroom, warm-colored LEDs create a cozy atmosphere.
On the other hand, in offices and laboratories, cool-colored LEDs are bright and have the effect of increasing concentration.

In addition, LED lighting with variable color temperature has recently become more common, allowing users to adjust the color temperature according to their preferences and environment.
The same lighting equipment can now provide light tailored to different atmospheres and purposes.

Color temperature has a significant impact on lighting quality and user comfort, so choosing the right one is important.
Advances in LEDs have made lighting more customizable and can now flexibly provide light in a variety of color temperatures.





Written by: BARREL Editorial Department
Supervised by: Yuki Oe (Lecturer, Department of Lifestyle Design, Faculty of Human Culture, University of Shiga Prefecture)
Lecturer at the University of Shiga Prefecture, Faculty of Human Culture (Department of Lifestyle Design).
She specializes in architectural environments, light environments, lighting environments, and color environments.
She is a member of the Architectural Institute of Japan/Illumination Institute of Japan.
After completing her doctoral course at Nara Women's University Graduate School of Humanities, she worked in technology planning at Sharp.
She worked as an assistant professor in the Faculty of Science and Technology at Tokyo University of Science and as a part-time lecturer at Osaka Jonan Women's Junior College before reaching her current position.