Monitor Test
Eight image-quality test patterns in one tool — color, gradient banding, contrast, gamma, brightness steps, viewing angle, sharpness, and aspect ratio — switched instantly with no reload.
About this tool
This is an eight-mode image-quality test pattern generator for monitors, laptops, TVs, and phone screens — Color, Gradient, Contrast, Gamma, Brightness, Viewing Angle, Sharpness, and Aspect Ratio — all rendered client-side and switched instantly with a toolbar, arrow keys, or Prev/Next buttons. Nothing reloads between modes, so you can flip back and forth quickly to compare patterns side by side in your head.
Each mode targets a different, specific failure mode a display can have. Color accuracy, gradient smoothness, contrast range, gamma tracking, brightness step visibility, off-axis color/contrast shift, pixel-level sharpness, and scaling correctness are mostly independent properties — a panel can nail one and fail another — so this tool keeps them as separate, purpose-built patterns rather than one generic "test card."
Key features
- Eight distinct test patterns on one URL, switched instantly via toolbar, Prev/Next, or Left/Right arrow keys
- Gamma mode renders real stripe-density patterns computed per target gamma (1.8 / 2.2 / 2.4) next to a fixed mid-gray reference for the classic squint test
- Fullscreen mode via the Fullscreen API, hiding all toolbar chrome so the pattern fills the entire display
- Per-mode instructions that explain exactly what to look for and how to interpret what you see
- Pure vanilla JS/CSS — no canvas, no images, no external libraries
Why use it
- Sanity-check a new monitor, TV, or laptop screen across multiple image-quality dimensions in one sitting
- Diagnose a specific complaint — banding, washed-out shadows, an odd color cast off-angle — by isolating it to a single test pattern
- Verify display scaling/aspect ratio is correct after changing a resolution or connecting through a scaler, adapter, or capture device
Why monitor testing matters
Panel quality varies significantly even within the same model line, and a display's out-of-box settings are frequently tuned for "pop" in a showroom rather than accuracy — oversaturated colors, an aggressive gamma curve, or brightness pushed high enough to crush detail at both ends. Working through a structured set of test patterns is the fastest way to notice these issues yourself, rather than discovering them later while editing photos, watching a dark movie scene, or just noticing something looks subtly "off" without being able to say why.
Tips for accurate results
- Test at your display's native resolution — scaling can introduce blur that has nothing to do with the panel itself, especially in the Sharpness and Aspect Ratio modes.
- Use fullscreen mode for Gradient, Contrast, and Gamma so the browser chrome and page background don't interfere with your perception of the pattern.
- For the Gamma test, view from a normal, straight-on distance and let your eyes relax rather than staring intently — the squint-test effect relies on the stripes blending optically.
- Repeat the Viewing Angle test at a few different distances — some shifts are more obvious up close, others only show from further back.
Frequently asked questions
Why do the gamma stripes look right at one target but not another?
That's expected and useful information — most displays are calibrated for approximately gamma 2.2, so a display running that curve should match the 2.2 reference most closely while the 1.8 and 2.4 rows look visibly off. If it matches a different target best, your gamma is tracking closer to that value.
Is banding in the Gradient test always a display problem?
Not always — the source signal, the graphics driver's color depth, and even browser rendering can introduce banding independent of the panel itself. If banding also shows up in photos or video from other sources, the panel is more likely the cause.
What counts as a "failed" Aspect Ratio test?
Any visible stretching — a circle that reads as an oval, or grid squares that read as rectangles. A correctly configured display and scaling mode should render both as true circles and true squares.
Does this replace a professional colorimeter?
No. This tool relies on your eyes and gives you a fast, qualitative read across several common failure modes; a hardware colorimeter measures actual light output and produces calibration data these visual patterns simply can't.