Monitor Test — Color, Uniformity & Backlight Bleed

How to use

1. Go full screen. Click Full screen so the pattern fills the display edge to edge with no browser chrome in the way.
2. Step through the patterns. Use the arrow keys or click to move through solid colors, the gradient, and the grid.
3. Inspect each one. On solid colors look for patches that differ, on black check the corners for bleed, on the grid check geometry.

Why test this

A monitor can look fine on a desktop and still hide problems that only a controlled full-field pattern reveals. Solid colors expose uniformity issues like patches that read warmer, cooler, or dimmer than the rest of the panel. A pure black field is the only reliable way to judge backlight bleed and IPS glow around the edges, the kind of flaw you want to catch within the return window of a new display. A smooth gradient surfaces banding from a weaker panel or heavy color settings, and a grid pattern checks geometry and sharpness into the corners. Run these before you commit to a monitor, after unboxing, or when something simply looks off. The result tells you whether the issue is the hardware, a cable, or a setting, and it is the fastest way to separate a real defect from your own eyes playing tricks.

What the results mean

There is no score here. You are the instrument, so what matters is what you see. On each solid color the screen should be even from corner to corner. A tint or a darker zone in one area points to uniformity drift, which is common but should stay subtle. On the black field, dim the room lights and look at the edges. Faint glow on IPS is normal, but distinct bright clouds or bars are backlight bleed and a fair reason to exchange a new panel. The gradient should fade smoothly. Clear steps or stripes mean banding. The grid should stay perfectly straight with crisp lines all the way into the corners. Step through every pattern in full screen, ideally in a dim room, and trust repeated observation over a single glance. Defects are easiest to confirm when you move between black and white a few times.

FAQ

What should a good monitor look like on these patterns?

Solid colors should be even corner to corner, black should be uniformly dark, the gradient should be smooth with no bands, and the grid lines should stay straight.

What is backlight bleed?

Light leaking around the edges of an LCD on a black screen. A little is normal on IPS panels; large bright clouds are a defect worth a return.

Why does the gradient show stripes?

Visible bands mean the panel or its settings are showing fewer shades than the gradient contains, common on 6-bit + FRC panels or with aggressive color settings.

Can I run this on a phone or TV?

Yes. It works on any screen with a browser. Full-screen support varies on iOS, but the patterns still fill most of the view.

Is this monitor test free?

Yes. It runs entirely in your browser, needs no installation, and stores nothing.

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