New-display buyers, people assessing a used screen, and anyone adjusting picture settings can use the patterns for a side-by-side visual check. Sit at a comfortable viewing distance and make sure the displayed image is scaling as expected before judging fine lines or small details.
How to use Monitor Test Patterns
- Choose a pattern type from Pattern mode: Grid, Checkerboard, Grayscale, Black to white · horizontal, Black to white · vertical, Nine patches, Vertical alternating lines, Horizontal alternating lines, or Text.
- Select Start Test to begin. Use Previous and Next to change patterns, or press the Left and Right arrow keys.
- To move through patterns automatically, press Space. When reduced motion is enabled, progression stays manual.
- Select Fullscreen or press F to enter fullscreen. Press Escape to leave, or select Exit fullscreen when it appears. On phones, an Exit button stays on screen.
- In fullscreen, tap the left or right half of the screen to move to the previous or next pattern. Select Reset or press R to return to the starting state.
When to use it
- Before a new monitor’s return period ends: Look over several patterns for visible issues while you still have time to contact the seller.
- Before buying a used display: Check different pattern types for obvious irregularities before completing the purchase.
- After changing picture settings: Compare a pattern before and after an adjustment, keeping the viewing distance and setup consistent.
- To inspect dark and bright steps: View the black and white level patches and notice whether the steps appear distinct to your eye.
- When a screen looks uneven: Use Nine patches and the gradient patterns to look for areas that appear different from the rest.
- To check fine lines and scaling: Grid, Checkerboard, and the alternating-line patterns can make visible edge or scaling differences easier to spot.
- For a quick text appearance check: Select Text and view it from your usual working distance.
Tips for a useful visual check
Work through several patterns rather than relying on one view. If something looks unusual, revisit it with Previous and Next, then compare again under the same display settings and viewing conditions. These patterns reveal how the screen looks to you; they do not provide a calibrated reading.
The black and white level patches are arranged left to right, then top to bottom. Each patch uses the same value for all three RGB channels:
| Patch set | RGB values, in order |
|---|---|
| Black levels | 0, 2, 4, 6, 8, 12, 16, 24, 32 |
| White levels | 224, 232, 240, 244, 248, 250, 252, 254, 255 |
The legends stay outside fullscreen, so check them before entering fullscreen if you need to refer to the values. Stop if bright patterns cause discomfort.
Limits of Monitor Test Patterns
Monitor Test Patterns exposes requested browser RGB values, not calibrated measurements of brightness, color, or display performance. What you see is also affected by scaling and the display’s current settings, so use the patterns for visual inspection and comparison rather than to verify a specification.
This is a first-pass check: it cannot repair a screen, confirm that a monitor is defective, or identify the cause of every visible issue. For a more focused visual check, try the Dead Pixel Test or the Black Level Test and White Level Test. If a problem remains apparent, contact the seller or display manufacturer.