An eye for details
In Microsoft Teams Rooms and all meeting/teaching spaces there’s a direct connection between asthenopia (eye strain) and the environment.
We are in an intermediate technology phase where signage technologies (dvLED, LFDs, flat panels etc) are being used for serious content, where viewers need to see and engage with content for extended durations. This is unlike signage, where users look away after they’ve seen what they need.
Eye strain is often designed into systems. Asthenopia is the fatigue caused by our eyes constantly adjusting to large differences in light levels (the ciliary muscles expanding and contracting the iris to protect the retinal nerves arrays).
What’s the benchmark for reading for indefinite periods without eye strain? The printed page. White paper has a gain around one, meaning that even under maximum recommended lighting of 500 lux (45 foot candles) the luminance (‘brightness’) is only around 160 candela/m2 [‘nit’] (45 foot-Lambert).
What does this mean? It means the black levels in a display are the most important thing.
Meeting and teaching displays only need to be in the 100-300 cd/m2 (30-90 foot-Lambert) range.
When dvLED displays are often rated at > 5000 cd/m2 (1460 foot-Lambert), it’s maybe nice that lecturers and presenters can warm their hands on the display on cold mornings. But a shame that unnecessary thousands will be spent on electricity during its lifetime. And on the additional heating and ventilation.
Projection has a smallest carbon footprint. In manufacture and in running costs. It uses the smallest amount of valuable metals/minerals, is the easiest to recycle - and creates the least volume of toxic landfill at end of life.
We are notionally shocked at the elaborate packaging on supermarket vegetables. But it’s there because at the moment we buy it, it’s easier. Tomorrow we’ll work out how to schlep them home loose. Always tomorrow. Today’s convenience = tomorrow’s landfill.
Posted: 8th June 2023