Understanding CIE 54.2 requires mastering three key angular parameters. These are non-negotiable for any retroreflection measurement system (e.g., a goniophotometer).
Most surfaces scatter light. When a beam of light hits a flat wall, it diffuses in many directions. This is why you can see the wall from various angles. However, this makes the wall appear relatively dim at night when viewed from a car. cie 54.2
It wasn't just any red. Crimson was romantic. Scarlet was theatrical. Burgundy was mournful. But CIE 54.2 was precise: a dominant wavelength of 614 nanometers, a purity factor of 0.87, and a luminance of exactly 12%. It was the red of a fire truck, a stop sign, a panic button. It was the color the human eye processed fastest, triggering the amygdala before the frontal lobe even knew what was happening. Understanding CIE 54