Eli5: What is a CIE colour space and what is its significance?


I am looking at LEDs and trying to understand the link between their brightness, temperature and colour.

In: Physics

There are two elements when describing what “color” something is – the pure physics answer of “what different wavelengths of light are being given off” and the human-senses answer of “what color does this look like”. Translating from the first one to the second one involves a whole bunch of facts about the structure of the eye, the way the cells in your eye respond to light, and the way the brain assembles all this info into what you “see”.

The CIE (or the Commission Internationale de l’éclairage – or the International commission on illumination) was a group of scientists who studied how we perceive light. They put together a standard translation between light wavelengths and observed color.

One thing that might be important for your LED lights is their Color Rendering Index. You know how if you look at something under only red light, everything looks different colors? The CRI is a number from 0 to 100 that says how much this particular light will distort the colors of things it shines on. 100 is perfect, and the higher the better.