VID-04
Display Brightness (AVIXA ISCR)
ANSI/AVIXA V201.01 · ANSI/AVIXA D401.01 · ANSI/AVIXA D402.02
Capacity and layout
The drawing appears when the inputs are complete
- 01Determine the display luminance required to hold the ISCR contrast ratio for each of the four viewing categories, accounting for ambient light reflected off the screen.
- 02Tip. Measure ambient illuminance at the screen face pointing back into the room, not at the desk. It is the light falling on the display that raises its black level and destroys contrast, and that is almost always lower than the working-plane figure in the lighting schedule.
- 037 : 1 — Passive viewing
- 0415 : 1 — Basic decision making
- 0550 : 1 — Analytical decision making
- 0680 : 1 — Full motion video
AVIXA ISCR contrast requirements
ANSI/AVIXA V201.01 — Image System Contrast Ratio — sets the minimum contrast a display must achieve in the room it is actually installed in. Contrast, not brightness, is what determines whether content can be read: ambient light falling on the screen is reflected back and raises the black level, and a display that cannot hold its ratio against that reflected light will look washed out however many nits it claims.
Viewing categories
Four categories, each with a minimum system contrast ratio set by how much detail the viewer has to extract from the image.
Use cases
- Passive viewing 7:1 — digital signage, ambient content
- Basic decision making 15:1 — presentations, text
- Analytical decision making 50:1 — detailed images, CAD
- Full motion video 80:1 — critical viewing, cinema
Formula
System contrast = (L_white + L_ambient) ÷ (L_black + L_ambient)
ANSI/AVIXA V201.01
Reflected ambient light
The light a screen throws back at the viewer is what destroys contrast. It depends on the illuminance at the screen face and the diffuse reflectance of the screen surface, so a low-reflectance or anti-glare panel needs materially less luminance for the same result.
Use cases
- Matte LCD panel ≈ 0.15 reflectance
- Anti-glare treatment ≈ 0.05
- Glossy panel ≈ 0.4
- ALR projection screen — rejects off-axis ambient
Formula
L_ambient = (E × R) ÷ π
E in lux at the screen, R diffuse reflectance
A common shortcut sets required luminance at three to five times the ambient level. That assumes a screen reflectance of 1.0 and a black level of zero — neither is true of a real display, and the shortcut overstates the requirement on a low-reflectance panel. This tool carries the actual reflectance and native black level through instead.
- 01Image contrast, all four viewing categories — ANSI/AVIXA V201.01ISCR
- 02Performance verification — ANSI/AVIXA D401.01
- 03Commissioning and acceptance — ANSI/AVIXA D402.02