The Value of Visual Comfort
When designing your lighting system, it is best to follow
the path of least resistance. That is,
the path of least resistance for the eyes of the occupants utilizing the
light. The eye is a marvelous organ and
can adapt to a wide variety of conditions.
However, like any other organ or muscle, when overexerted it can become
exhausted; and exhausted eyes makes for an exhausted occupant.
Hence, you should keep in mind three factors to maximize
visual comfort for occupants when you are designing new or upgraded lighting
1) Color Balance
eye has three types of color receptor cells, or cones. Though the human eye can perceive light with
wavelengths in the range of 400-700 nm, often called the spectrum of visual
light. Each of the three cones has a
specific wavelength of light in that range where they are most sensitive. To achieve the maximum visual comfort, light
should be balanced between the wavelength sensitivities of these three cones.
caused when there is a significant difference between the luminance of what
someone is focusing on and another light source. Instinctively, humans shy away from significant
variations in luminous intensity (as someone shies away from a flashlight
pointed at their face). Intense pockets
of luminance inhibit visual perception through the constriction of the pupils,
reducing brightness, and the scattering of bright light with the eye, reducing
contrast. Depending on its severity,
glare can create either visual discomfort or visual impairment (imagine driving
towards the sun at sunrise or sunset).
Lighting systems should be designed to eliminate or significantly reduce
glare as much as possible.
on the task, the definition of light uniformity may vary. In general, a fixture or lamp is considered
to have light uniformity when luminous intensity and color are balanced across
the range over which that fixture or lamp diffuses light. When light lacks uniformity, the eye wastes
its energy adapting to various light levels and reconciling color
discrepancies. Uniform light enables the
eye to conserve its energy and focus on what it does best, seeing.
The best lighting systems do their job without you even
knowing they’re there. And that’s
because they take into account the three factors outlined above. Careful planning in the design process is the
For tips on how to save money while designing your new
lighting systems, visit the enLIGHTen America website, www.nemasavesenergy.com.
08-17-2010 11:32 AM