Screen gain
How much brighter the screen is on-axis than a perfect diffuse (Lambertian) white surface.
- Standard
- SMPTE RP 94 (gain vs Lambertian reference)
- ISO 21118
- Context
How to compare it
Screen gain
1.0 is reference. Above 1 is brighter on-axis but with a narrower viewing cone, and below 1 (grey) gives deeper blacks at the cost of brightness.
Half-gain angle(°)
The viewing angle at which luminance drops to half the peak.
Wide seating needs a large half-gain angle.
Standard: SMPTE RP 94
Marketing traps
- Screen gain: Gain isn't free light. It redistributes light towards the centre and narrows the cone. High gain also increases hot-spotting and sparkle.
Deep cut
Screen gain. RP 94 measures luminance at 5° steps against a Lambertian reference standard. Peak gain alone hides the angular falloff, so `half_gain_angle` is required.
Terms on this page
Screen gain
Reflectivity relative to a matte white reference (1.0, Lambertian), measured per SMPTE RP 94 at 5° intervals. Gain above 1 is brighter on-axis but narrows the viewing angle and can cause hotspotting and sparkle. ⚖ (screen entities) screen.gain
Half-gain viewing angle
The angle at which luminance falls to 50% of peak. ⚖ screen.half_gain_angle_deg