Check a new monitor before the return window closes
Test a new monitor the day it arrives: cycle red, green, blue, white and black for pixel faults, hold black in a dim room for backlight bleed, hold gray for uniformity, and run a black-to-white gradient for banding. Every fault on that list is easiest to act on inside the return window.
The short version
- Set native resolution and clean the glass. Test at the panel's native resolution with the factory picture mode, after a wipe: dust and scaling artifacts both impersonate defects.
- Cycle the five pixel fields. Red, green, blue, white and black full screen, inspected closely. Any dead or stuck pixel on a brand-new panel is grounds for a return, whatever the defect policy tolerates.
- Hold black in a dim room. Backlight bleed shows as bright patches leaking from edges and corners. Judge at normal brightness and viewing distance; every LCD glows a little in a pitch-black room.
- Hold gray, then run the ramp. A mid-gray field exposes uniformity problems and tinted patches. A black-to-white gradient exposes banding: the smooth ramp should have no hard steps.
A new monitor has one brief period in which every fault is fully refundable, and it is measured in days. The manufacturer's defect policy may tolerate a stuck pixel or two after that; the return window tolerates nothing you dislike. Fifteen minutes of flat color fields, run the day the box is opened, moves every discovery you might make over the coming months into the period when it is still free to act on.
Set up the test honestly
Run the panel at its native resolution and factory picture mode, and wipe it down first. Dust impersonates dead pixels, and a non-native resolution adds scaling softness that impersonates focus problems. You are trying to see the panel, not the setup.
Pixels first
Cycle red, green, blue, white and black, full screen, inspecting each closely. The five fields catch what any single color misses, because most pixel faults are a single failed subpixel that only shows against its own channel or its absence. The dead pixel guide covers the classification; the position to take on a brand-new panel is simpler than any policy table. Day-one pixel faults are what return windows are for.
Black, in a dim room
Hold a black field with the lights low. On an LCD, the backlight is always on behind the panel, and imperfect edge sealing leaks it: glow and bright patches at borders and corners. Calibrate your judgement to your life, not the worst case. Every LCD betrays something in a pitch-black room at full brightness; the question is whether you can see bleed at the brightness and distance you will actually use. Uneven blotches deserve less patience than faint symmetrical corner glow, and IPS panels' shallow angled shimmer is a panel characteristic rather than a defect.
An OLED sits this test out: its black is pixels-off, and any glow against true black on an OLED is a different and rarer conversation.
Gray, then the ramp
Mid-gray is the merciless field. Partial drive is where panels vary most, so uniformity problems, faint tinted zones and the smudgy patchiness reviewers call dirty-screen effect all surface on gray while white looks flawless. Scan it slowly at normal distance.
Finish with a black-to-white gradient. The ramp should climb smoothly through every gray; hard vertical steps are banding, meaning fewer distinct levels are surviving the trip from signal to glass. Rule out the cable and any vivid picture modes first, then judge. A panel that bands at native settings will band in every dark film you ever watch.
Fifteen minutes, five fields, one ramp. Then either enjoy the monitor or repack it while the label still prints for free.