Questions & Answers
Q. I have one question which is not related to this webinar but I want to know answer about this. In ICAO Annex 14 chapter 5 for runway edge lights. Paragraph 220.127.116.11, it’s mentioned variable white runway edge lights. What’s the meaning of variable white?
A. In a chromaticity diagram, variable white refers to a region that represents the range of colors achievable by adjusting the color temperature of a light source without changing its chromaticity coordinates. The chromaticity diagram is a two-dimensional representation of colors, showing the relationship between the red, green, and blue components of a light source.
The color temperature of a light source is a characteristic that describes the color appearance of the light emitted. It is typically measured in Kelvin (K). A higher color temperature, such as 6500K, corresponds to a cooler, bluish light, while a lower color temperature, such as 2700K, corresponds to a warmer, reddish light.
In the chromaticity diagram, the variable white region represents all possible color temperatures within a specific color space, such as the sRGB or Adobe RGB color space. The color temperature scale ranges from warm white to cool white, and any color temperature within this range can be achieved by adjusting the intensity of the red, green, and blue components of the light source while keeping its chromaticity coordinates fixed.
For example, a white LED light source can be adjusted to produce different color temperatures within the variable white region without changing the actual color of the light (i.e., its chromaticity coordinates). This allows for flexible lighting solutions that can cater to different preferences and lighting requirements, such as warm lighting for a cozy ambiance or cool lighting for a more energizing environment.