Manual solid fields
Select RGB, CMY, black, white, or grey and keep a suspect coordinate in view. Manual mode is best when you need time to scan the panel or compare a point across specific channels.
Recent this session
Preset, custom, split, and ramp fields
Screen Color Test
The screen color test presents RGB, CMY, black, white, neutral greys, and validated custom HEX/RGB fields. Run them manually or in a conservative auto sequence, isolate primary channels, compare two colors side by side, or inspect a simple saturation ramp.
Choose the mode for the question
Four ways to use the screen color test
Automatic sequence
Auto mode advances through the active sequence every three or five seconds. Reduced-motion preferences enforce the slower interval, and the sequence pauses when the tab is hidden.
Two-color split
Split mode places the current color beside a second validated HEX field. It helps reveal an obvious side-to-side response or compare two requested backgrounds, not measure a color difference.
Saturation ramp
The simple ramp keeps the selected hue and approximate lightness while increasing CSS HSL saturation from left to right. Visible steps may involve rendering, processing, or the panel; they do not prove a particular bit depth.
A repeatable channel workflow
Check RGB response without claiming calibration
- Start with red, green, and blue. Enable channel-only mode if the suspected point or patch appears tied to one primary. Compare the same screen location while each channel fills the field.
- Add cyan, magenta, and yellow. Each CMY field combines two requested RGB channels. A colored point may blend into some combinations and contrast with others, providing more descriptive evidence.
- Verify on black, white, and greys. These fields separate bright-on-dark, dark-on-bright, and mid-tone observations. Broad patches should be checked with the dedicated uniformity workflow.
- Recreate a useful background. Enter a six-digit HEX value or integer RGB channels from 0 to 255. Recent custom colors stay only in the open page and clear when it reloads; they are not transmitted.
- Compare representative content. A solid field removes visual clutter but can exaggerate differences that are not visible in normal work. Record both observations instead of treating the browser tool as a pass/fail meter.
The output path matters
Why screen color test output is not a measurement
A HEX value defines a browser color request. The visible result passes through browser rendering, the operating-system color pipeline, ICC profiles, GPU output, connection or internal link, display picture modes, and panel electronics. Wide-gamut displays may also map untagged or CSS colors differently from a calibrated production workflow.
Your eyes can notice a large tint shift, a fixed subpixel, a band, or a region that responds differently. They cannot derive a reliable numerical gamut boundary or Delta E from an unreferenced field. A colorimeter or spectroradiometer, appropriate software, and defined targets are needed for color measurement and calibration.
Interpret simple patterns carefully
What screen color test split fields and ramps can—and cannot—show
Useful visual observation
A sharp left/right difference can make broad tint or brightness behavior easier to locate. A ramp can expose obvious contouring, clipping, or a region that changes differently across saturation. Repeat the result after checking color profiles, night modes, HDR state, and display processing where relevant.
Unsupported numerical conclusion
Do not translate a visible ramp step into panel bit depth, a split difference into Delta E, or vivid primaries into gamut coverage. Screens, browsers, and human adaptation do not provide the controlled reference required for those values.