Photometry [foh-tom-i-tree]
noun
- measurement of the intensity of light or of relative illuminating power
- the science dealing with such measurements
Cone photometrics chart
Photometrics charts are just one of the many tools used by professional outdoor (and indoor) lighting designers. Basically, the chart tells a lighting designer how much light there will be at a certain distance away from the light source, and how wide that light beam will be. Terms like lux, lumens and candelas are also related to the measurement of light, and important factors in any lighting application.
Each LED, halogen or incandescent fixture or lamp should have a corresponding photometrics chart that demonstrates to the designer/specifier how much light the source is producing at distances up to about 20’ or more, and how large a light pattern will be produced from the source at that distance.
In the landscape lighting industry, manufacturers provide these charts for every fixture. They are available for a very wide variety of fixtures and lamps, such as spot lights, flood lights and even path lights. Professional lighting designers will be able to consult these charts to determine exactly how many path lights will be needed along a certain distance, and how much light will actually be produced to illuminate that pathway. For moon lighting, we are able to determine how wide the beam of light will be, and how much will be on the ground if we place a fixture 25’ high in a tree, for example. Using photometry and the corresponding fixture chart, our skilled designers are able to determine how many of these down lights are needed in a certain tree, and where they should be aimed to achieve our lighting goals for the client.
Although we consider ourselves experts in the artistry of outdoor lighting design, the science behind light behavior and measurement is a critical tool that contributes to the final portrait we wish to create. If you would like to see how art and science come together to light your home, please contact us here.
