Wednesday, January 8, 2014

More light ≠ better vision

Hyperventilating politicians occasionally assert that people talking about light pollution want to throw us all back to the dark ages. In fact, nothing could be further from the truth, and these photos by George Fleenor show why:

Security lighting by George Fleenor is licensed under a
Creative Commons Attribution-NonCommercial 4.0 International License.

The unshielded security light produces a great deal of glare, which makes it difficult to see the man standing at the yard gate. With well designed lighting, you can actually reduce the total amount of light (saving lots of energy) while at the same time actually improving visibility.

The video below also demonstrates very dramatically how poorly your eye is able to judge luminance. For vision in a typical urban night environment, the total amount of light plays a relatively small role in determining how well you can see. The more important factor is how the light is distributed.

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