How to Achieve a Large Light Source Area
Previously, we made the point that task lighting fixtures should have a large surface area of uniform brightness. These characteristics reduce shadowing and reduce glare from reflections of the light source. Because task lighting is a pioneering area, there are no established guidelines for fixture surface area. As explained in Reference Note 51, experiments suggest that there should be a ratio of at least 1:5 between the average width of the fixture’s radiating surface and the distance between the fixture and the task.
There are two approaches for reducing the brightness of lamps, using diffusers and using reflectors. The two differ in light loss, control of the light distribution pattern, ability to shield the lamp from view, and ease of installation. We’ll talk about diffusers first, then reflectors.