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Display Check Guide

A reference for the DeskTest.net Display Check - a guided grading suite for a monitor, TV, or laptop screen. It explains what each full-screen pattern is actually showing you, why five of the six checks are honest visual inspections rather than measurements, how the automatic HDR and wide-gamut read works, and how to turn the results into a decision: keep the panel, adjust a setting, or return it.

Open Display Check →

What Display Check does

Display Check walks you through six checks that grade the physical quality of a screen. Five of them paint a controlled full-screen pattern - solid colors, a black field, a checkerboard, a moving box, smooth gradients - that makes a specific defect easy to see with your own eyes. You look, then mark Looks good or Problem. The sixth check is automatic: it reads what the display and browser advertise for HDR and wide color gamut. The tool then combines your marks and the capability read into one grading verdict and a plain-text report you can copy or mail to your IT team.

It is built for the moments when a screen might be defective: accepting a batch of new monitors, deciding whether a laptop panel is bad enough to warranty, checking a lobby TV before it goes on display, or diagnosing why one workstation's screen looks off.

Why these are visual checks, not measurements

This is the most important thing to understand before you trust a result. A web browser can paint any color on the screen, but it has no light sensor. It cannot see the panel. That means it is physically impossible for this tool - or any browser tool - to objectively measure backlight bleed, burn-in severity, or pixel response time in numbers. What it can do is draw the exact pattern that makes each defect visible, and record the judgment of the person looking at it.

So the honest framing is: checks 1-5 are guided visual inspections. The "Pass" or "Problem" you mark is your eye's call, not a laboratory reading. That is a real, useful signal - a human looking at the right test pattern catches dead pixels, bleed, and ghosting reliably - but it is not the same as a colorimeter or a photodiode. For color-critical work or formal acceptance testing, back it up with a hardware probe.

The sixth check (HDR and gamut) is also not a quality grade. It reports capability flags the display and browser expose. A monitor can advertise HDR and still tone-map badly; a browser that does not understand a query will report the feature as unsupported even on a capable panel. Treat it as "what the hardware claims," not "how good it looks."

Display Check vs. Display Test vs. Refresh Rate

DeskTest.net has three display tools that overlap a little. Use the right one:

ToolBest for
Display TestThe basics: resolution and color-depth read-out, solid colors and bars, a quick dead-pixel cycle, and multi-monitor sanity. Start here for a fast look.
Refresh Rate TestMeasuring the effective refresh rate in Hz (is that 144Hz panel actually running at 144Hz, or stuck at 60?).
Display Check (this tool)The deeper grading pass: backlight bleed and uniformity, OLED burn-in, response-time ghosting, gradient banding, and an HDR/gamut capability read, rolled into one report. Use it when you need to grade a panel, not just confirm it works.

How to run it

  1. Set the room. For the backlight-bleed check especially, dim the lights. Bleed and IPS glow are only visible against a truly dark field in a dark room; in a bright office you will see nothing and pass a panel that actually bleeds.
  2. Open a pattern. Each check has an Open full-screen pattern button. It fills the whole screen and shows a short hint at the top of what to look for.
  3. Cycle and inspect. Where a check has several fields (five solid colors, black then gray, and so on), click anywhere or press the ← / → arrow keys to move between them. The current field is named in the bottom-left corner.
  4. Exit. Press Esc, or use the Exit button, to leave the overlay at any time. The overlay is a normal page layer, not a hard fullscreen lock, so Esc always works.
  5. Mark it. Back on the page, set that check to Looks good or Problem. The verdict and progress count update immediately.
  6. Repeat for all five, then Copy report or Send to your IT.
Best-effort fullscreen: the tool asks the browser to go fullscreen so no address bar or taskbar sits over the pattern. If the browser refuses, the overlay still covers the page. Either way, Esc exits.

The five visual checks, one by one

1. Stuck / dead pixels

The screen fills with solid red, then green, blue, white, and black. Against each flat field, a bad pixel stands out: a stuck pixel stays one color (a bright red or blue dot on a field that should be white or black), while a dead pixel stays black on every color. Move close and scan the whole surface, corners included, on each color.

What to do if you see one: a stuck pixel sometimes recovers after several minutes of rapid color cycling; a truly dead (always black) pixel does not recover in software. Most manufacturer warranties allow a return above a certain dead-pixel count - check the terms before you buy or before you contact the vendor. For a customer-facing screen, replace it.

2. Backlight bleed / uniformity

Two fields. On black, look at the edges and corners for bright clouds or streaks - that is backlight bleed on an LCD, or the bluish corner haze called IPS glow (which shifts as you move your head, and is normal in moderation). On mid-gray, look for patches that are noticeably brighter or darker than the rest, or a cloudy blotchiness called mura. Both are only visible in a dark room; run this one with the lights off.

Bleed and mura are backlight problems and cannot be fixed in software. Mild IPS glow is expected on IPS panels. Heavy, distracting bleed on a new monitor is a valid warranty return.

3. OLED burn-in / image persistence

Solid white, gray, and primary fields plus a high-contrast checkerboard. On an OLED (or older plasma) panel that has shown static content for a long time - a taskbar, a channel logo, a dashboard - you may see a faint permanent ghost of that content, or areas where color is unevenly worn. Sweep through the fields and watch for any shape that stays put across different colors. Temporary image retention often fades after the panel runs varied content for a while; true burn-in is permanent.

LCDs do not burn in, but they can show temporary image persistence; the same patterns reveal it. If you see a fixed ghost on an OLED used for signage or a dashboard, plan rotation or replacement, and enable the panel's pixel-shift and screen-saver features.

4. Response time / ghosting

A box glides smoothly back and forth across a gray field, driven frame-by-frame by the browser's animation loop. On a slow panel, the pixels cannot change color fast enough to keep up, so you see a faint trail or smear following the box, or a doubled edge. A fast panel shows a crisp box with clean edges.

Honest limit: this is a ghosting look, not a millisecond figure. The tool draws smooth motion and you judge the smear; it does not and cannot report a gray-to-gray response time. Panel overdrive settings (often called "Response Time" or "Overdrive" in the monitor menu) change how much you see - too much overdrive causes inverse ghosting (a bright trail). If motion looks smeary, try the next overdrive level up in the monitor's own menu.

5. Color banding / gradient smoothness

Smooth black-to-color gradients for gray, red, green, and blue. A good 8-bit (or higher) panel blends them into one continuous ramp. A cheaper 6-bit panel, or a system sending a limited color signal, shows visible steps or vertical stripes instead of a smooth blend. Some mild banding is normal on 6-bit-plus-dithering panels.

If banding is bad: in your OS display settings raise the color depth to the highest available; in the graphics driver (NVIDIA, AMD, or Intel) set output color depth to the maximum and the range to Full RGB; and if you are on HDMI, make sure it is not defaulting to a limited-range YCbCr signal.

The HDR and wide-gamut capability read

This check makes no pattern and needs no judgment - it queries the browser and reports what the display advertises:

Read it as a claim, not a grade. "High" dynamic range means the pipeline reports HDR capability; it does not mean the panel tone-maps well or gets bright enough to matter. A blank or "not reported" value often just means the browser does not implement that media query, not that the hardware lacks the feature. Because gamut is nested (Rec. 2020 contains P3 contains sRGB), the tool reports the widest one that matches.

Reading the verdict and report

The verdict panel at the top summarizes your marks plus the capability read:

Copy report puts a plain-text summary on your clipboard: overall status, the auto HDR/gamut/color-depth read, each check's Pass/Problem mark, the honest "what this cannot do" note, and your browser and origin. Send to your IT drops the same text into a mail draft (to your support address when the page was opened with a ?support= parameter). View report shows the exact text inline first. Nothing is uploaded - the report is assembled in this tab, and the page makes no network requests at all.

For IT admins

Display Check is a no-install way for a helpdesk or a receiving desk to grade panels consistently. A few notes:

Elsewhere on the web: