2. Estimate your lamp fixture, mounting height, lamp type and wattage.
3. The Photometric isofootcandle diagram for the fixture you have chosen show points of equal brightness from the fixture at a specific mounting height connected by a continuous line. Use the multipliers to compute the footcandle levels for your application if your mounting height or wattage are different from the example given.
4. If needed adjust your mounting height, wattage or spacing to get the footcandle levels necessary for your specific job
For multiple fixture application, isofootcandles values can be added where the curves intersect.