Can I fix color fringing myself, or does it need a repair shop?

Most fringing on flat-panel displays is software-caused (sharpening, ClearType, scaling) and fixable in settings — try resetting your monitor's sharpness to a neutral value and disabling GPU sharpening filters first. Fringing on a projector is usually adjustable via its built-in convergence menu.

Does convergence error still happen on modern LCD or OLED monitors?

True convergence error is rare on flat panels because sub-pixels are fixed at manufacturing rather than beam-aimed like on old CRTs. What looks like fringing on a modern monitor is much more often caused by display sharpening, font rendering (ClearType), or scaling.

Why does the fringing look worse near the edges of my projected image?

This is a classic sign of optical convergence drift in a multi-chip or 3-LCD projector — the separate red/green/blue light paths diverge more toward the edges of the lens's field of view, which is why edge fringing specifically points to the projector's own convergence adjustment as the fix.

Should I run this test at native resolution?

Yes — running your display at anything other than its native resolution forces scaling, which can itself introduce fringing-like artifacts that have nothing to do with real convergence. Set your display to native resolution before testing for the most accurate read.

Does browser zoom affect this test?

Yes — zooming breaks the pixel-perfect 1:1 rendering the test relies on. Reset your browser zoom to 100% and reload the page if you've changed it.

Convergence Test

The Convergence Test draws single-pixel white lines and a fine crosshatch on a black canvas so you can spot colour fringing along high-contrast edges — a red or blue halo where a line should be pure white usually means sub-pixel misalignment or an aggressive sharpening filter. Click Enter Fullscreen to fill the display, then look closely at line intersections and edges for any tint that shouldn't be there. This matters most on projectors and on panels with non-standard sub-pixel layouts, so browser zoom breaks the pixel mapping — keep zoom at 100% or the result won't mean anything. The free flicker test is free and runs entirely client-side, so nothing about your display is ever uploaded.

Convergence & Fringing Canvas

Look at the line intersections and edges for red, green, or blue fringing that shouldn't be there on a properly converged display.

What Causes Convergence Errors and Colour Fringing

A display renders every pixel using separate red, green, and blue sub-pixels that combine to form the color you see. Convergence refers to how precisely those sub-pixels line up — when they're perfectly aligned, a white line on a black background looks like a single crisp white line. When they're misaligned, that same line shows a colored fringe (typically red or blue) along one or both edges, because the red and blue sub-pixel contributions are shifted slightly out of position relative to green. The subpixel test online is free and runs entirely client-side, so nothing about your display is ever uploaded.

On modern flat panels, true convergence error in the classic CRT sense is rare, since each pixel's sub-pixels are physically fixed in place during manufacturing rather than aimed by an electron beam. What shows up as apparent "fringing" on an LCD or OLED panel today is far more often caused by aggressive display sharpening, sub-pixel rendering used for font smoothing (like ClearType), or — on projectors specifically — genuine optical convergence issues from the projector's lens system.

Convergence in Projectors vs. Flat Panels

Projectors, especially older 3-chip or 3-LCD models that combine separate red, green, and blue light paths through a lens system, can develop real optical convergence drift over time as the lens or internal optics shift slightly — this produces genuine color fringing that gets worse toward the edges of the projected image, where the light paths diverge most. Most projectors include a manual or automatic convergence adjustment in their setup menu specifically to correct this. The frame skipping test runs fullscreen so you can inspect your panel edge-to-edge under real viewing conditions.

On an LCD or OLED monitor, by contrast, each pixel's sub-pixel layout is fixed at the factory and can't drift — so fringing on a flat panel almost always traces back to a software-side cause: display sharpening filters (in the monitor's OSD or your GPU driver), Windows ClearType font rendering (which deliberately uses colored sub-pixel adjustments to make text look sharper), or the scaling method used when a lower-resolution signal is stretched to fill a higher-resolution panel.

How to Read the Crosshatch Test Pattern

The fine crosshatch grid and single-pixel lines in this test are drawn at your display's actual device pixel ratio specifically so each line is exactly one physical pixel wide — this precision matters because any softer, anti-aliased line would introduce its own blur that could be mistaken for fringing. Look closely at where horizontal and vertical lines cross: a color halo (commonly red on one side, blue or cyan on the other) along any of these lines indicates fringing, whether from a projector's optical convergence or a flat panel's sharpening/scaling settings.

If you zoom your browser or change your OS display scaling between viewing the test, the pixel-perfect alignment breaks — reload the page after making scaling changes to get an accurate read again.

When Fringing Is Fixable vs. Permanent

Software-caused fringing — from sharpening filters, ClearType, or scaling — is fully fixable: try setting your monitor's OSD sharpness to its middle/neutral value, disabling any GPU-driver sharpening filters, and testing with ClearType tuned or temporarily disabled through Windows' font settings. Optical convergence drift on a projector is usually adjustable through the unit's built-in convergence menu, though it may need periodic re-adjustment. True convergence error baked into a flat panel at manufacturing — genuinely misaligned sub-pixels — is rare, but when it does occur, it's a hardware defect, not something you can correct, and is a legitimate case for a warranty return.

Frequently Asked Questions

Can I fix color fringing myself, or does it need a repair shop?: Most fringing on flat-panel displays is software-caused (sharpening, ClearType, scaling) and fixable in settings — try resetting your monitor's sharpness to a neutral value and disabling GPU sharpening filters first. Fringing on a projector is usually adjustable via its built-in convergence menu.
Does convergence error still happen on modern LCD or OLED monitors?: True convergence error is rare on flat panels because sub-pixels are fixed at manufacturing rather than beam-aimed like on old CRTs. What looks like fringing on a modern monitor is much more often caused by display sharpening, font rendering (ClearType), or scaling.
Why does the fringing look worse near the edges of my projected image?: This is a classic sign of optical convergence drift in a multi-chip or 3-LCD projector — the separate red/green/blue light paths diverge more toward the edges of the lens's field of view, which is why edge fringing specifically points to the projector's own convergence adjustment as the fix.
Should I run this test at native resolution?: Yes — running your display at anything other than its native resolution forces scaling, which can itself introduce fringing-like artifacts that have nothing to do with real convergence. Set your display to native resolution before testing for the most accurate read.
Does browser zoom affect this test?: Yes — zooming breaks the pixel-perfect 1:1 rendering the test relies on. Reset your browser zoom to 100% and reload the page if you've changed it.