Color temperature and brightness

Unit: absolute temperature (Kelvin, K)

The color temperature is expressed by the absolute temperature K, which is to heat a standard blackbody (such as platinum). When the temperature rises to a certain degree, the color begins to change gradually from red, orange, yellow, green, blue, indigo (blue violet) and purple. Using the characteristics of this light color change, when the light color of the light source is the same as that of the blackbody, we call the temperature of the blackbody at that time as the color temperature of the light source. When the color temperature is about 3000K, the light color is yellow. When the color temperature is above 5000K, the light color is blue. Light with different color and temperature has different lighting and visual effects. Different color temperatures correspond to different colors of light, as shown in the figure below. Different wavelengths cause different color feelings for human eyes, from red, orange, yellow, green, blue, indigo (blue purple) and purple. The sensitivity of the eye varies strongly with the wavelength.

For example, under good lighting conditions, the eye is 20 times more sensitive to 550 nm wavelength light (yellow light) than red or blue light. This is also an important reason why the fog lights of most cars and street lights on the road use yellow light. Color temperature is the standard to measure color temperature, not the brightness of the lamp. The color temperature of halogen lamp can range from 2300K to 7000K; The color temperature of HID lamp ranges from 4200k to more than 8000K; The higher the color temperature of the lamp, the worse its penetration into fog and rain (the less bright it is). So far, large manufacturers such as Philips only produce xenon lamps with a maximum color temperature of 6000K. The following is the performance of different color temperatures:

Light color warm light effect

3000K yellow light, strong penetration

4200k white with yellow, the original vehicle is equipped with xenon lamp

5000K light all white, European maximum color temperature

6000K light all white, slightly blue

Day in 6500k sunlight

7000-8000k white with obvious blue

The penetration of blue light above 8000K is very poor. It is recommended that the color temperature of about 6000K is just the color temperature at which the whitest color starts to turn blue slightly. It is easy for human eyes to accept, not easy to fatigue and improve safety, while halogen lamps are poor.