Ambient lighting is becoming increasing popular, providing gentle illumination in a variety of places, but considering how our visual system works, perhaps it should not be applied everywhere.

With advances in LED technology and reductions in cost, it is now possible to bring a splash of color to almost any space. Philips Hue is one of the most notable examples for the home. Using a mobile device, the bulb can be set to almost any color. Ambient lighting is being used outside the home for safer cycling. A glow from the wheels readily alerts motorists to nearby cyclists.

A striking example of automotive interior ambient lighting can be found in the new Mercedes Benz S-Class. The image shows red light being thrown onto almost every surface: around the instrument cluster, under the dash, along the center console, and on the door panel. This lighting shows off the curves of the dashboard, but perhaps more interestingly, it illuminates surfaces that are already backlit. Take, for example, the windows switches on the door. The symbols on the switches are backlit in light blue. On top of this, the switches and surrounding areas are illuminated in red. Although additional illumination could seem useful at night, this use of ambient lighting could actually reduce the driver’s ability to see.

The eye is particularly sensitive to contrast, or the relative brightness of an object and its surroundings.

Contrast is the difference in luminance and/or color that makes an object (or its representation in an image or display) distinguishable. In visual perception of the real world, contrast is determined by the difference in the color and brightness of the object and other objects within the same field of view.

Continuing with the window switch example, at night a driver might wish to locate the rear window lock, a button that is infrequently used and requires a quick glance to find it. By illuminating the surface of the button, the contrast between the backlit lock symbol and the surrounding area is reduced. The eye’s sensitivity to contrast is greatly reduced in low-light, so maximizing contrast while driving at night is particularly important.

Ambient light additionally creates visual clutter, illuminating features of the car’s interior that are not essential to driving the car. Although the lines of the dashboard and console are beautiful, these features do not provide the driver with necessary information. In an effort to reduce unnecessary visual distractions at night, Saab introduced ‘Night Panel’. When activated, all backlighting is extinguished except for the speedometer, reducing distractions. Only when needed will gauges re-illuminate, for example, when running low on gas.

Ambient lighting in any setting can inspire and awe, but its applications in the automotive space should be considered carefully. Especially while driving at night, designers ought to illuminate just what needs to be seen to ensure attention remains focused on the road ahead.

Photo credit: The DiLauro Dossiers