Color Test

Introduction

The DeviceHub Color Test is a free online solid-field inspector that paints primary and secondary colors across your display so you can judge tint, obvious channel failures, and gross panel issues in the browser, no calibrator hardware required for a first look. Designers checking whether a conference room panel is wildly off, PC builders verifying a new IPS or VA screen, photographers spotting a strong green cast before a client review, and support staff asking users to “put up red” on a call all benefit from simple full-bleed fields. Open the page, go fullscreen, and cycle red, green, blue, and common secondaries plus black and white. DeviceHub does not claim to replace a spectrophotometric calibration lab; browser CSS colors pass through OS color management and the panel’s own processing. What you see is a practical visual check. Combine with Gradient Test for banding, Gamma Test for tone, Dead/Dead Pixel Tests for discrete defects, and Color Blindness Test when the question is confusion simulation rather than panel health, remember that color-blindness content is educational, not a medical diagnosis. Before anyone books a calibrator or argues about ICC profiles, a full-bleed primary field answers coarser questions: is a channel obviously weak, is the panel wildly tinted, and do solid colors reveal sparkles that belong on pixel tools instead? DeviceHub’s Color Test paints primary and secondary solids across the display for that first-look visual inspection, no hardware meter required, and no claim that CSS fields replace a spectrophotometric lab. Designers checking a conference-room panel before a client review, PC builders verifying a new IPS or VA screen, photographers spotting a strong green cast, and support staff asking a user to “put up red” on a call all benefit from simple labeled fields. Browser colors still pass through OS color management and the panel’s processing, so what you see is a practical check rather than Print-accurate soft proofing. Combine with Gradient Test for banding, Gamma Test for tone, Dead and Dead Pixel Tests for discrete defects, Monitor Uniformity Test for blotchy gray, and Color Blindness Test when the question is educational confusion simulation, not a medical diagnosis. HDR Test remains a sibling for browser/CSS/media capability signals only, never a calibrated HDR laboratory meter. Permissions stay none: schools can run the fields without camera prompts or installers. Call-center scripts that ask users to open a red field and describe casts work better when both sides share DeviceHub’s labeled solids instead of hunting for a random image online that may be compressed or watermarked. Keep night-light off for those calls when possible so “warm” is not confused with a failing backlight.

What this tool does

Controls present solid fields and maybe labeled swatches. Guidance covers fullscreen, disabling warm night filters, and comparing two monitors cautiously. The tool does not write ICC profiles or adjust GPU digital vibrance. It does not upload photos of your screen. HDR versus SDR can radically change punchiness, document which mode you used. Pair with HDR Test for capability signals only, not calibrated luminance meters. Controls cycle red, green, blue, cyan, magenta, yellow, white, and black with guidance to disable night-light tints when documenting. DeviceHub does not write ICC profiles, does not adjust GPU digital vibrance, and does not upload photographs of your screen. HDR versus SDR can change punchiness dramatically, note which mode you used on any ticket. Comparing two monitors requires matched brightness and matching SDR/HDR state; otherwise you are comparing tone maps more than panel health. Sparkles on a flat primary should send you to Dead Pixel Test and a local cable reseat, not to a compressed video-call screenshot as gospel.

When to use it

Use Color Test during unboxing, after profile installs, when a single channel looks weak in games, and before trusting softproof assumptions on an unknown lounge monitor. Prefer Gamma/Contrast/Black/White Level tools for tone and clipping. Prefer Uniformity for clouding on gray. Prefer Gradient for stair-steps in skies. Prefer Color Blindness Test for educational simulation of confusion, not clinical screening. Use Color Test during unboxing, after profile installs, when a game’s reds look crushed on only one PC, and before trusting softproof assumptions on an unknown lounge monitor. Prefer Gamma, Contrast, Black Level, and White Level tools when tone and clipping dominate; prefer Uniformity for clouding on gray; prefer Gradient for stair-steps in skies; prefer Color Blindness Test for educational CVD simulation only. Retail associates can prove a floor unit is not stuck in an absurd vivid preset before a customer wheels it out. After cleaning sprays, wait for residue to dry, wet glass tint is not a panel defect.

How it works

CSS or canvas fills output RGB values through the browser’s color pipeline into the compositor. Wide-gamut panels may render web colors differently than sRGB-centric expectations. No permission prompts. Night Shift and f.lux alter fields, disable for documentation. Remote desktop compression posterizes solids. This is visual judgment, not ΔE instrumentation. CSS or canvas fills output RGB through the browser’s color pipeline into the compositor and finally the panel. Wide-gamut displays may render web colors differently than sRGB-centric expectations, educational, not a ΔE certificate. No permission prompts appear. Night Shift, f.lux-like tools, and “eye care” overlays alter fields; disable them for warranty-oriented documentation. Remote desktop codecs posterize solids and invent false noise, inspect on the machine attached to the panel. OLED automatic brightness limiter behavior can dim sustained full-field white; do not confuse ABL with a failing backlight on a brief white check.

Step-by-step instructions

1. Disable temporary color filters when practical, set the display to a known SDR mode if comparing panels, and open Color Test fullscreen.
2. Cycle primary and secondary fields, noting casts, sparkles, or uneven patches as you scan.
3. Check white and black fields for tint and for dead/stuck pixel clues, then escalate to specialized pixel or uniformity tools if needed.
4. If skies or ramps are your concern, continue to Gradient and Gamma Tests with the same display settings.
5. For HDR capability questions, open HDR Test and treat it as browser/CSS/media signals, not a lab meter.
6. Exit when finished; no revoke step is required.

Common problems

Expecting Print-accurate colors from unmanaged browser fields disappoints, use hardware calibration for that. Different browsers map colors slightly differently. OLED ABL can dim full-field white. Dirty screens tint unevenly. Claiming “factory defective” from one warm field under night light wastes RMA time, retest neutral. Expecting magazine-print accuracy from unmanaged browser fields disappoints, hire or borrow a calibrator for that job. Safari, Chrome, and Firefox can disagree slightly on color-managed output; document the engine. Dirty screens create uneven tint patches that look like uniformity failures until wiped. Declaring factory defect from one warm field under night light wastes RMA time, retest neutral. Phone photos of colored fields add white balance lies; trust eyes on the glass for first-pass judgments. Extensions that inject dark-reader filters recolor fields silently, use a clean profile when documenting RMA-oriented screenshots.

Privacy explanation

Color fields render locally. DeviceHub does not collect your panel’s color responses. No camera permission is required. Close the tab to end the UI. Screenshots for tickets remain your files. Solid fields never become a cloud color profile DeviceHub stores about your panel. No camera permission is required. Screenshots for tickets remain your files; close the tab to end the UI on shared PCs. Retail demo stations benefit from bookmarking Color Test beside Dead Pixel Test so a single visit covers tint and discrete defects without juggling manufacturer control panels that differ on every SKU. When documenting a cast for a ticket, note browser name, SDR versus HDR mode, night-light state, and approximate brightness so a remote technician can reproduce your viewing conditions instead of arguing about memory of “too green.” If secondaries look fine but one primary collapses, reseat the cable and compare another input before assuming the panel lost a whole subpixel channel, GPU and scaler faults can mimic channel failure on solids alone.