What black level is needed in Teams Room displays?
How bright do they need to be in hybrid spaces? (And how much power is wasted driving too bright displays?)
As part of a series of short articles, Visual Displays' Director Greg Jeffreys discusses all things AV…
Looping back to Microsoft's Front Row digital canvas concept (section, top right), three things stand out here: low luminance, great black levels - and a completely matt display. This is a space you could work in all day without asthenopia (eye strain).
'Brightness' is a problem word as it refers to how we see light, not its measurable attributes. The key human factor is contrast: the difference between white and black levels on the same image at the same time.
In Teams rooms and hybrid spaces, contrast is effectively a function of ambient light - whether flat panel or projection. But if we have good contrast are we all good? Unfortunately not.
The problem with contrast is that it's a relative. Your black levels could be, say, 300cd/m2 (nit) and so long as the while levels were 15 times higher (4500cd/m2) then you'd theoretically tick AVIXA's PISCR/ISCR standards' boxes - and design in an extreme levels of asthenopia (eye strain).
The datum needed to pin the contrast ratio to required display luminance levels is therefore the black level. It takes minutes to do using the calculator screen grab below.
Ping me if you want a copy of the Excel sheet.
Posted: 8th February 2022