How to read a photometric report?

Photometric reports provide precious information about a source’s intensity and flux, illumination, luminance, glare and much more. If you are in the lighting industry, chances are that you have already seen these types of reports and graphics. Used mostly for specification-grade projects, most lighting manufacturers provide technical sheets with all the lighting characteristics. They are an effective way to measure the lighting output, effect and efficiency of the lighting.

The most important graphs are the candela chart (Fig 1.1) and the candela distribution curve (Fig 1.2). They effectively provide information about the beam’s projection angle, the angle of elevation and the intensity measure in candelas (cd).

In order to take make these charts, there are measures taken and repeated at the lamp axis (0°), 22.5°, 45°, 67.5° and perpendicular axis (90°) with 0°, 45° and 90°as primary angles. This provides a range of light intensities at different levels and potential glare conditions.

Here are some useful insights you can take from looking at photometric reports:

  1. Type of lighting (Direct vs Indirect).
  2. Symmetry of the distribution (Symmetric or asymmetric).
  3. Type of distribution (Narrow or wide pattern)
  4. Smooth or rounded pattern
  5. Glare or no glare production

Did you know Arani offers lighting simulations? If you would like to see the lighting simulation, simply send us your project details and we will provide you lighting solutions tailored to your specifications and an accurate visual with the lighting results. Try it today!

polar candela distri

Fig 1.1


candela chart

Fig 2.2

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