Testing Methodology
ScreenVitals separates controlled visual patterns, user observations, and camera-derived estimates so that a convenient browser test is never presented as laboratory certification.
Visual pattern tests
The browser displays CSS-generated solid colors, grayscale levels, gradients, grids, and moving shapes at the available viewport resolution. Full-screen mode removes most browser controls, but operating-system overlays, scaling, HDR tone mapping, browser color management, GPU settings, and display processing can still influence the result.
Photo uniformity analysis
The analyzer downsizes the photo, samples luminance across a grid, normalizes tile values around the median, and calculates relative variation. The heatmap highlights areas that are brighter or darker than the photographed field. Gray and white photos can receive a relative 0–100 score for repeat comparison under the same setup. Black photos receive only a qualitative Low, Moderate, or Strong variation result because camera noise and automatic exposure make a precise dark-screen score misleading. Neither output is suitable for comparing unrelated devices or proving a manufacturer specification.
Factors that can alter a photo result
- Automatic exposure, HDR, night mode, and local tone mapping
- Lens shading, distortion, dirt, or reflections
- Camera angle and distance
- Screen brightness, local dimming, and automatic brightness
- Moiré between the camera sensor and display pixel grid
- Color filters, white balance, and panel viewing angles
Refresh-rate estimate
The refresh tool samples browser animation frames with requestAnimationFrame and reports a median interval. It measures the active browser presentation rhythm, which is useful for checking configuration. In the guided health check, this estimate is compared with the refresh rate selected by the user; a lower result is flagged for settings, cable, input, GPU, and monitor-mode review. It does not read the panel electronics and cannot certify pixel-response time.
Safety choices
The stuck-pixel color cycle is rate-limited, includes a flashing-content warning, requires explicit acknowledgment, and can be stopped immediately. ScreenVitals never recommends pressing, rubbing, heating, opening, or striking a panel.
Editorial review
Guides are reviewed for internal consistency with the tools and their limitations. We distinguish what a user can observe from what would require measurement hardware, manufacturer diagnostics, or professional service. Corrections can be sent through the contact page.
Last methodology review: August 28, 2026.