Achieving proper light levels
Light levels are most commonly expressed “Foot Candles” (fc). The Illuminating Engineering Society (IES) Lighting Handbook provides detailed light level recommendations for thousands of specific applications. General rules of thumb are:
- Visual Tasks of medium contrast or small size require 50–100 fc*
- Visual Tasks of low contrast or very small size require 100–200 fc*
- Users over the age of 65 should be provided with 2 times the lux or foot candle light levels.
* * IES Lighting Handbook 10th Edition
What to look for in the light produced from a task light
Supports IES foot candle recommendation for the task: Understanding the user and the task at hand will dictate how much light is required. Photometric maps illustrate the footcandle power over a specific distance and area.
High lumens per watt: The higher the lm/W the more efficient the light.
White light color: “White” light is typically perceived between 3200–4100 K. Light less than 3200 K begins to appear orange or red, while light above 4100 K begins to appear blue.
Color Rendering Index (CRI) above 80: CRI determines how “true” colors appear. CRI below 80 will begin to make objects appear noticeable different from natural sunlight.