# Screen Tester Pro

> Professional display calibration tool. Test dead pixels, backlight bleed, color accuracy, gamma and more - in one click.

Canonical page: [https://chrome-stats.com/d/screen-tester-pro](https://chrome-stats.com/d/screen-tester-pro)

## Overview

- **ID:** `screen-tester-pro`
- **Platform:** Firefox
- **Type:** Firefox add-on
- **Status:** Available
- **Publisher:** BeYor
- **Category:** web-development,appearance,photos-music-videos
- **Daily users:** 1
- **Version:** 1.0.1
- **Last updated:** 2026-04-09
- **First published:** 2026-04-03
- **Size:** 1.25 MB
- **Data as of:** 2026-09-06
- **Store listing:** [Firefox Add-ons Store](https://addons.mozilla.org/firefox/addon/screen-tester-pro/)

## Description

<em>Screen Tester Pro gives you instant access to 10 professional display test patterns directly in your browser:</em>

<strong>RGB &amp; CYMW</strong> - check color purity and accuracy
<strong>Gradient</strong> - detect banding and bit-depth issues
<strong>Checkerboard (3 sizes)</strong> - pixel sharpness and contrast
<strong>Focus text</strong> - font rendering at all sizes
<strong>Dead pixels</strong> - auto-cycling solid colors to spot stuck pixels
<strong>256 colors</strong> - full spectrum and grayscale ramps
<strong>Backlight bleed</strong> - pure black for dark-room edge testing
<strong>Geometry</strong> - straight lines, diagonals, and circle for distortion
<strong>Gamma</strong> - dither matching to verify gamma accuracy
<strong>Subpixel</strong> - single-pixel alternating colors for fringing

<strong>Features:</strong>
✓ Fullscreen mode (F key)
✓ Hide UI for unobstructed testing (H key)
✓ Keyboard shortcuts for all patterns (1–0, arrow keys, Space)
✓ Brightness overlay slider (+/- keys)
✓ Mouse coordinate display
✓ Built-in help screen (? key)
✓ Works 100% offline — no data sent anywhere

## Rankings

- #111,800 — Overall
- #3 — screen caster

## Permissions and access

### Permissions

- `tabs`

## Safety

- **Risk impact:** Moderate risk impact
- **Risk likelihood:** Moderate risk likelihood

### Analysis details

- Grants access to browser tabs, which can be used to track user browsing habits and history, presenting a privacy concern.
- This extension has low user count. Unpopular extensions may not be stable or safe.

> Some risk analysis details are omitted from this free response. [Upgrade to view the full analysis](https://chrome-stats.com/pricing).

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Source: [Chrome-Stats](https://chrome-stats.com/d/screen-tester-pro)