Why does BMW use orange lights for the instrument illumination?
BMW vehicles have an iconic red / orange interior glow at night which dates back to the 1970s. There is no doubt this is hue pleasing to the eye, but why did BMW stick with the color orange after all these years? There is science behind the reasoning for this choice that can be easier explained by learning how the human eyes work in dark environments.
How does the human eye receive light?
The human eye has two types of photoreceptors located in the retina which receive light, the rods and cones. Rods are responsible for low light vision and the cones are responsible for high light vision. The rods are extremely sensitive to light, more than 1,000 more sensitive to light than the cones.
When looking at the light spectrum chart above, the colors on the far right (red / orange) are furthest from ultraviolet rays (sunlight) and closest to infrared rays (invisible to the eye). This makes the colors red and orange ideal choices night vision as we will further explain below.
Why are red / orange lights used in BMW instrument clusters at night?
Longer wavelength colors such as red / orange, have the least amount of impact on our night vision. This capability allows our eyes to focus on red / orange lighting and then back to dark, dim light without loss of focus on objects thus preserving our night vision.
Navy ships, for example, use all red interior lighting at night. This allows a sailor to step outside at night and preserve his night vision putting the least amount of strain on his eyes. If Navy ships would alternately use a white light inside, when the sailor stepped outside, his eyes would not easily be able to detect dimly lit objects at night. It would take about 30 minutes for the eyes to full adjust to the new dark environment to provide maximum vision.
Although red lights are ideal for night vision, it does not provide ideal clarity with small details. As a result, BMW compromises to using a longer wavelenght color on the spectrum to orange. The wavelength of orange allows for an ideal compromise between night vision and clarity of the instruments.
BMW orange interior lights use a wavelength of 605 nanometers.
What other industries use red lighting at night?
Because the science of red light at night is not disputed, it can be found in many other industries providing the same benefits as BMW’s get for night time use. Other uses of red light at night can be seen on:
What are other advantages of using orange light?
Another other reason for the orange light use is that it is pleasant to look. Orange is a warm color that our brain naturally reacts to positively. Similar to seeing a sunset, sunrise, or a candlelit in a dark room that give off warm colors our body reacts positively to it as a comforting color. Furthermore, red light therapy is used by some doctors to help calm patients before bed and improve sleep quality.
What’s the bottom line?
Long-wavelength colors such as red and orange allow preserving the human eye’s night vision capabilities. The human eyes can glance at the instruments and back to dimly lit objects outside the vehicle without having to readjust to the dark.
New BMW models feature digital instrument clusters with a full spectrum of colors that can be distracting without a uniform glow like analog dials. This digital cluster setup defeats the purpose of the older model’s illumination to help nighttime visibility. Modern BMW models also allow you to change the color of the interior trim lighting. Although it may be fun to change the interior lighting colors, it could also have an impact on your night vision. As a result, it is recommended to retain the orange or red color to retain function while also keeping the classic nighttime ambiance BMW is famous for.