The Right Light
In the mid-’90s, Ford Motor Company came to Orfield Labs because the older workers at inspection stations in the plant were missing numerous defects in the vehicle bodies they were checking. Orfield Labs found that the lights in the quality-control room generated so much glare that the workers’ visual acuity was shot after the first 20 minutes. Orfield and his crew showed Ford how to reduce and redirect the light, improving worker performance.
In certain lighting research projects, Orfield Labs uses a device called an “imaging photometer,” a computerized light meter that combines the technology of a video camera and a computer. “It assigns a luminence value to each pixel within the frame,” Role says. “And it tells you how much light is being reflected off of a surface in an area.”
The device was invented by the Institute for Building Performance of the National Research Council of Canada. Initially, only four were made, and those were targeted to go to universities. Orfield flew to Ottawa in 1990 and persuaded the NRC that it would be to its advantage to let him take one of the four and report back on its performance. Most users, Orfield says, put the device to work on one repetitive task. Orfield Labs had a broad research agenda that it believed would be a much better test of the technology.
Orfield Labs has used the photometer to conduct various kinds of visibility research. When Role takes the photometer into an office workspace, he sets it up at the level of the seated occupant and measures glare and contrast ratios—and determines the visual comfort of the worker. The device hasn’t just been used indoors: In 1997, an officer from the Minneapolis Police Department’s Safe Unit came to Orfield with a problem: At night, the cops couldn’t see well enough to recognize the criminals in the street—even with the streetlights on. Orfield Labs put its photometer to work.
“Instead of shooting light down to the ground, the light shoots straight out at people,” Orfield says of the streetlights. “And they are thousands of times as bright as the street or sidewalk. So the older you are, the more likely you won’t be able to see what you are doing because of these lights.”
Orfield and his crew first proposed a project in which lighting vendors would pay the city to test their streetlight designs, with the hope of securing a long-term contract with the city. He also recommended that Minnesota establish a new standard for elderly visibility—which, as a bonus, would also make urban lighting more energy efficient. (At this point, Orfield hopes that the city will take further action on developing this standard.)
But the problems that especially fascinate Orfield are the difficulties that buildings create.
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