Backlight Bleed Test
Fullscreen fills use a bitmap canvas (not a styled div) for true black and gray levels, avoiding some GPU compositing / layer-edge artifacts.
How to test
- Set brightness to your normal level
- Use View Fullscreen in a dim room; the frame is drawn with
CanvasRenderingContext2D - Scan corners and edges for lighter patches (bleed)
- Check off-axis warm haze (IPS glow)
- Use Uniformity for clouding / dirty-screen effect
Backlight bleed: Light leaking from edges, usually corners
IPS glow: Shifts with viewing angle — often normal on IPS
Clouding: Uneven brightness / DSE on solid fields