Porch light
partly shielded600 lumens at 2.6 m, on from 19:00 to 23:00.
Puts about 13.6 lux on the seat.
The front porch nobody sits on
What changes after dark?
During the day distance hides you. At night being the brightest thing in the frame puts you on stage.
At 21:00
At this hour the seat is much brighter than the ground the observer is standing on, which is what makes a person read clearly from outside.
Light on the seat
13.6
lux
Thrown sideways and up
22
per cent of output
Most visible to
83
People on the sidewalk
Who can see you, and why
| Who | Line | On you | On them | Contrast | Reads as |
|---|---|---|---|---|---|
| People on the sidewalk | open | 13.9 lx | 1 lx | 14× | lit up |
| The house opposite | open | 13.9 lx | 0.4 lx | 35× | lit up |
Contrast is the ratio between the light on you and the light where they are standing. Being three or four times brighter is what makes a person read clearly at a distance a daytime sightline would hide.
The fixtures
Shielding guidance follows DarkSky International. The principle that does the work is simple: light the ground, not the sky, the neighbour or yourself.
Other questions about this place