DisplayHDR 1.2 explainedSame number.
Different requirements.

Minimum white luminance is a floor for a named certification test, not a typical-brightness claim or a ceiling on the product’s output. Likewise, a lower permitted black level is a stricter limit in that test. Neither number describes every scene, mode, or individual retail unit.

HDR10 support and DisplayHDR certification are different claims. HDR10 concerns the content signal; DisplayHDR adds defined performance requirements for a display. A retailer’s “HDR400” label is not enough to establish either the complete certification or the tested model. VESA explains the distinction; its older pattern example describes CTS 1.1.

CTS stands for Compliance Test Specification. Two displays can share a tier while using different editions: VESA lists AOC AG275UXM2 at DisplayHDR 1400 under CTS 1.1 and Hisense 27G7K-Ultra at DisplayHDR 1400 under CTS 1.2. These are directory observations checked on 29 October 2026, not a head-to-head product review.

VESA currently lists 400, 500, 600, 1000, and 1400 tiers in both families. True Black 1400 was introduced in July 2026. An older official chart can be accurate for its date and still omit a current tier.

Does DisplayHDR 400 require local dimming?

Classic DisplayHDR 400 under CTS 1.2 can meet its contrast requirement with sufficiently improved native panel contrast or 1D local dimming. Classic 500/600 require 1D local dimming or better; classic 1000 and above require 2D local dimming or better. Those backlight categories must not be applied to emissive True Black displays.

A tier does not tell you the zone count or every dimming transition. If a bright cursor beside dark content matters, seek evidence of that behavior on the exact model. Do not divide a peak minimum by a black maximum from a different test to invent an on-scene contrast ratio.

Shadow detail and subtitle stability are separate checks

The black-crush check asks whether near-black shades remain distinguishable. The HDR-versus-SDR black check concerns SDR content with the operating system in HDR mode. The subtitle-response check concerns unwanted luminance changes elsewhere in the scene; it does not certify eye comfort, PWM behavior, motion clarity, or universal “flicker-free” operation.

1. Capture the identity.Copy the manufacturer model, regional suffix, panel size, resolution, and display option. For a laptop, the product family alone may not identify the installed panel.
2. Match the family and tier.Search the exact model in the relevant directory section. Check “Family Models” for documented aliases. Similar spelling does not establish equivalence.
3. Keep the CTS version beside the badge.Record the family, tier, edition, source, and lookup date together. A record labeled 1.1 does not become 1.2 because the overview page is newer.
4. Resolve a missing or ambiguous record.Request manufacturer or VESA confirmation for the configuration being sold. Until resolved, describe it as “not verified in the searched public record.”

VESA says not every certified product is approved for public listing. A directory miss is not proof of non-certification or fraud. A near match is not proof that an unlisted configuration is covered.

For an imported or regionally renamed display, ask the seller to connect the offered SKU to the documented family. An invoice without the panel option can leave the question unresolved. Save the specification and record you relied on; later comparisons should refer to the same configuration. Our portable monitor guides put those display claims alongside connection and carrying constraints.

No image at all? Start with USB-C display fault isolation or the dock detection guide. A missing display and an unsatisfactory HDR image are different problems.

Windows: select the intended display first

Open Settings → System → Display, select the HDR-capable screen, and check its HDR capability and setting. Then check the application and content. Battery policy can affect HDR availability or playback. Microsoft’s HDR settings guide explains the relevant controls.

If Windows shows certification as “Not found,” it can mean no certification or missing manufacturer-published certification metadata. Treat that message as a reason to investigate, not a definitive verdict. See Microsoft’s HDR requirements.

Mac: check the model, display, and connection

Apple’s HDR guidance qualifies support by Mac model, macOS, display, and content. Check High Dynamic Range in Displays when available. The “Optimise video streaming while on battery” setting can make HDR video play in SDR on battery. Confirm the adapter, input, and cable for the mode you intend to use.

Works directly, fails through the dock?

Keep the known-working direct connection as your reference. Compare the dock route with the same content, display input, requested mode, and power arrangement; change one element at a time. A route-dependent failure narrows the investigation but does not identify the faulty component by itself.

For the connection evidence, use the USB4 Version 2.0 display guide, Thunderbolt 5 display-support guide, or DisplayPort 2.1b and DP80LL guide. A connector’s shape is not a guarantee of the complete HDR mode.

1. Which exact configuration will I receive?Match the model, suffix, panel size, resolution, and display option. Ask for a documented alias if the listing and certification names differ.
2. What is the full certification?Record family, tier, CTS version, source, and lookup date. Request confirmation when the public record cannot settle the match.
3. Which input and power arrangement support my mode?Name resolution, refresh rate, operating system, application, route, and power. Include the dock if you plan to use one.
4. What does each brightness figure measure?Separate patch peak, full-screen flash, long-duration, typical, and additive-color values. Ask for area, duration, mode, and source.
5. What evidence addresses my actual concern?Text clarity, reflections, calibration, uniformity, and portability need their own evidence. A demonstration or suitable return opportunity can help assess what the badge cannot settle.