ScreenToolsScreen.tools

Contrast Ratio Test

Stacked black-and-white blocks to verify panel contrast.

Press F for fullscreen

About Contrast Ratio Test

A high-resolution chessboard of pure black against pure white. Useful for inspecting how the panel handles maximum-contrast adjacencies: bleed, ghosting near the squares, and color shift at the boundaries on low-end LCDs. The 8×4 grid lays the squares out at a comfortable size for inspection at arm's length.

Panel Contrast Verification

The high-contrast chessboard pattern tests how cleanly your panel renders maximum-contrast adjacencies. On a quality panel, the boundary between black and white squares is a perfectly hard edge with no visible ghosting, halo, or color shift. Lower-quality panels show gray bleeding at the edges of white squares into adjacent black areas, or a color tinge along the boundaries. VA panels typically outperform IPS in this test due to higher native contrast ratios. OLED panels render perfect contrast because black pixels are physically off. Use this test to compare panels or verify that your display meets its advertised contrast specifications.

Ghosting and Motion Artifact Check

While the contrast grid is static, it reveals optical artifacts that affect motion clarity. Look for ghosting — faint duplicate edges offset from the real boundary — which indicates slow pixel response times. Ringing artifacts appear as bright or dark lines parallel to the square edges, caused by over-sharpening in the panel's scaler. These artifacts become visible during fast-paced gaming and video playback. Competitive gamers and video editors use the contrast grid to evaluate whether a panel's scaler introduces unwanted processing artifacts that degrade image quality during motion.

HDR and Display Comparison Tool

When comparing HDR displays, the contrast grid reveals the practical difference between rated contrast ratios. An OLED panel at infinite contrast shows zero light bleed between squares, while a mid-range LCD may show gray haze across the entire grid. Place two monitors side by side running the same test for an immediate visual comparison. Home theater builders use this to select the best panel for dark-room movie viewing, and photographers use it to evaluate shadow detail reproduction in prints.

How to use it

  1. 01

    Press F for fullscreen

    The grid fills the panel — no chrome to distract or alter local contrast.

  2. 02

    Inspect the edges between squares

    Look for ghosting, ringing, or color tinge along the borders. A clean panel shows a perfectly hard edge.

  3. 03

    Download the current view as a PNG

    Click the download icon in the top-right toolbar — it sits between the settings gear and the fullscreen button. We detect your display's physical pixel count (screen resolution × device pixel ratio) and rasterize the current configuration into a Retina-sharp PNG. The file lands in your browser's default downloads folder; to save straight to the Desktop, enable 'Ask where to save each file' in your browser settings. The filename includes the resolution so you can keep multiple variants side by side.

Frequently asked

The shortest path between you and the answer.

Why an 8×4 grid?

Eight columns by four rows gives squares with roughly a 16:9 aspect at fullscreen, which keeps each cell roughly square on a standard monitor.

Is this tool free?

Yes. Every ScreenTools.co tool is free, with no account, no paywall, and no install.

Does it work on mobile?

Yes. Layouts adapt to phone and tablet screens. Mobile Safari restricts true fullscreen, but the page fills the viewport and you can add the page to your Home Screen for an app-like experience.

Does it work offline?

Once a tool's page has loaded once, the runtime is local. A few tools that fetch fonts or icons need the first hit online; after that, refresh works offline.

Does this collect my data?

No personal data leaves your browser. The site has lightweight, privacy-respecting analytics for aggregate counts (which tool was opened) and nothing else.

Related tools

All screen tests