🔲 Uniformity Test

Test your display's brightness uniformity and detect backlight bleeding, IPS glow, and clouding issues. Best performed in a dark room.

💡 Why This Test?

Uniformity refers to how evenly the backlight illuminates your screen. Poor uniformity can cause distracting bright spots, dark corners, or cloudy patches.

This is especially noticeable in dark scenes (movies, games) and affects the overall viewing experience. IPS panels often have "IPS glow," while edge-lit LCD panels may have backlight bleeding.

✅ What You'll Check:

Backlight bleeding (light leaking from edges)
IPS glow (viewing angle-dependent brightness)
Clouding (uneven brightness patches)
Vignetting (darker corners)
Overall brightness consistency

📖 How to Use This Test

Turn off room lights or test in a dark room
Set your monitor brightness to normal usage level (50-75%)
Click "Start Test" to enter fullscreen
Check each gray level pattern (0%, 5%, 10%, 25%, 50%)
Look at all four corners and edges carefully
Move your head slightly to distinguish IPS glow from backlight bleed

💡 Tip: IPS glow changes with viewing angle (move your head), while backlight bleeding stays fixed. Some bleeding is normal on most LCD panels.

📖 Test Guide

What to Look For:

• Backlight Bleeding: Light leaking from edges (mainly corners)
• IPS Glow: Viewing angle dependent bright spots
• Clouding: Uneven patches of light across screen
• Vignetting: Darker corners compared to center
• Banding: Vertical or horizontal strips of uneven brightness

How to Test:

1. Dim or turn off room lights
2. Set monitor brightness to normal usage level
3. Enter fullscreen mode (F11 or button below)
4. Check each gray level (0%, 5%, 10%, 25%, 50%)
5. Look for uneven brightness, especially at edges
6. Move your head slightly to distinguish IPS glow

Test Patterns

⚠️ Important Notes

• Some backlight bleeding is normal, especially in IPS panels
• IPS glow changes with viewing angle - move your head to check
• Test in a dark room for best results
• Excessive bleeding may worsen over time
• Consider RMA if bleeding severely impacts usage

🔧 Common Issues & Solutions

❓ I see bright corners (IPS glow) - is this normal?

Yes, IPS glow is an inherent characteristic of IPS panel technology, not a defect. It appears as a whitish-blue haze in corners when viewing dark content, especially in dark rooms.

How to distinguish: Move your head left/right - IPS glow changes with viewing angle, while backlight bleed stays fixed. Normal glow extends 5-10cm from corners at extreme viewing angles.

What to do: This is normal and cannot be "fixed." It's less noticeable at normal brightness (50%+) and in well-lit rooms. VA panels don't have IPS glow but have worse viewing angles.

❓ Dark spot in center or corners - panel defect?

A persistent dark spot visible on all brightness levels is likely a panel defect (dead backlight zone, pressure damage, or manufacturing defect), especially if it's circular or irregular.

Test method: Display pure white at 100% brightness. Dark spots that remain are panel defects. Check if it's visible in photos - phone cameras can reveal what your eyes might miss.

RMA criteria: Most manufacturers warranty covers spots larger than 5mm diameter. Document with photos and contact support. Vignetting (slight corner darkening) is normal on many displays.

❓ Entire screen looks cloudy/uneven - what's wrong?

Clouding is uneven backlight distribution creating patches of brighter areas, most visible at 5-25% gray levels. More common in edge-lit displays (LEDs only on edges) vs direct-lit (LEDs behind entire panel).

Severity assessment: Test at 5%, 10%, and 50% gray. If only visible at 5-10% in pitch-black room = acceptable. Visible at 50% brightness or in normal lighting = significant issue.

Solutions: 1) Lower brightness to 40-60% (reduces visibility), 2) Avoid pure black content (use dark gray themes), 3) Check bezel screws aren't too tight (rare fix), 4) Consider RMA if severe enough to impact usage.

❓ One corner much brighter than others - acceptable?

Isolated corner bleeding extending more than 2-3cm from the edge, visible at normal brightness (50%+) and in moderately lit rooms, exceeds normal tolerances.

Measurement: Set brightness to 50%, display pure black, measure lit room. If corner glow is visible and extends beyond 2-3cm, it's excessive. Take photos with phone at low exposure to document.

Action: Check warranty terms - many cover "excessive backlight bleed" if it's in the worst 5% of units. Loosen bezel screws slightly (if accessible) - over-tightening can cause edge pressure and bleed.

❓ Vertical bands of uneven brightness (banding)

Vertical or horizontal banding (repeating stripes of slightly different brightness) indicates LED backlight zoning issues or panel manufacturing variance. Most visible on 5-25% gray screens.

Panel type matters: Edge-lit displays show 2-4 vertical bands (corresponding to LED positions). Direct-lit show grid patterns. FALD (Full Array Local Dimming) can show zone boundaries in HDR content.

Acceptable vs defect: Subtle banding only visible in dark room at low brightness (<30%) = normal. Banding visible in normal lighting or at 50%+ brightness = defect, eligible for RMA. Check VESA FPDM-2 uniformity standards.