PQ vs HLG for HDR Monitoring: Key Differences Explained

If you need one rule for monitoring: monitor in the transfer function you plan to deliver, unless you have a specific, approved conversion path. Use PQ for HDR10, HDR10+, Dolby Vision, most studio HDR masters, and precision color review. Use HLG for live broadcast, fast-turnaround television, and workflows where the same signal needs to behave reasonably across a wider range of displays. That sounds simple, but the reason matters. PQ and HLG aren't just two “HDR looks” because they describe different relationships between signal values and displayed light. If the monitor, timeline, output device, and deliverable disagree about that relationship, the picture can look too dark, too bright, clipped, washed out, or “fine” on one screen and wrong everywhere else.

PQ and HLG solve different monitoring problems

ITU-R BT.2100 defines both PQ and HLG for HDR television production and programme exchange. HDR workflows usually pair both with Rec.2020 container colorimetry, although the actual graded image may sit mostly inside P3. Both can carry high dynamic range and wide color gamut images.

PQ behaves like a fixed brightness map, while HLG adapts to the display.

Aspect	PQ / ST 2084	HLG
Brightness model	Absolute display luminance	Relative scene-light based rendering
Signal meaning	Code values map to defined nit values through the PQ EOTF	Code values are interpreted according to display capability, system gamma, and environment
Typical use	HDR10, HDR10+, Dolby Vision, UHD Blu-ray, premium streaming masters	Live HDR broadcast, sports, events, fast-turnaround television, contribution workflows
Display behavior	More consistent on calibrated reference displays, but values above the monitor peak must be clipped, rolled off, or tone mapped	More adaptive across different displays, but appearance can vary more between monitor modes and rooms
Metadata dependence	HDR10 uses static metadata, HDR10+ and Dolby Vision use dynamic metadata	Does not rely on HDR10-style mastering metadata for basic display rendering
Main monitoring risk	Reviewing with the wrong peak target, tone mapping behavior, or metadata assumptions	Assuming flexibility means consistency, or treating HLG as a finished SDR substitute

The important difference is this:

PQ is absolute. A given PQ code value maps to a defined display luminance through the PQ EOTF, also known as SMPTE ST 2084.
HLG is relative. The signal represents scene-light relationships, and the display rendering depends on the screen’s peak luminance, black level, system gamma, and viewing environment.

That means PQ is better when you want a stable, mastering-oriented reference. If you put 203 nits, 600 nits, or 1000 nits somewhere in a PQ grade, those values have specific meaning. A properly configured PQ reference monitor should show them predictably, within the limits of that monitor. HLG is better when you need a signal that can adapt. The BBC and NHK developed it with broadcast in mind. Instead of depending on HDR metadata and an absolute mastering target, HLG lets compatible displays render the image according to their own capability and environment. That makes it attractive for live production, broadcast contribution, and situations where you can't control every receiving display. The takeaway: PQ is usually the choice for “this is the mastered HDR picture.” HLG is usually the choice for “this HDR signal needs to survive a real television pipeline.”

What “absolute brightness” means for PQ monitoring

PQ is designed around displayed light. The full PQ system can describe luminance up to 10,000 cd/m², even though current mastering monitors usually operate far below that. Common HDR mastering targets include 1000 nits, sometimes 4000 nits for specific workflows, with trims or tone mapping used for consumer displays that can't reproduce the full range. In a PQ monitoring workflow, the monitor follows the PQ EOTF to determine how bright the image should be. If the signal says a highlight is 1000 nits, the reference display either shows it at 1000 nits, clips it, rolls it off, or tone maps it depending on how your team configures the monitor. That configuration choice is a creative and technical decision. This is why PQ is common for:

HDR10 mastering
HDR10+ mastering
Dolby Vision base HDR grades and trims
UHD Blu-ray HDR deliverables
Scripted streaming HDR

PQ also tends to be easier to discuss across departments because values mean something measurable. A colorist, QC technician, and finishing supervisor can talk about diffuse white, specular peaks, clipping behavior, and MaxCLL/MaxFALL in concrete terms. But PQ has a real monitoring trap: the signal may contain values beyond what your monitor can reproduce. ITU operational guidance notes that PQ can encode information beyond the capability of a specific monitor if the signal isn't constrained to that monitor. So if you grade on a 1000-nit display but allow signal values far above 1000 nits, you need to know whether you're clipping, rolling off, or simply not seeing part of the encoded range.

PQ signals can contain highlight values a monitor can't fully display.

For creative monitoring, decide whether your reference display is acting as:

A hard reference at the mastering peak, such as a 1000-nit PQ monitor
A tone-mapped preview of a higher-brightness master
A consumer-behavior check, where you intentionally view how a less capable display maps the image
A QC display, where you inspect signal legality, clipping, gamut, and metadata

Those are different jobs. Don't let one monitor mode pretend to be all of them.

What “relative brightness” means for HLG monitoring

HLG doesn't assign every signal value to a fixed luminance in the same way PQ does, and it's built around a relative transfer system that adapts to display capability. A brighter HLG display can render a more expansive image, while a lower-brightness display can compress the result while preserving a usable picture. That flexibility is the reason broadcasters widely use HLG for broadcast HDR. In live production, you may have cameras, switchers, graphics, contribution links, SDR monitoring points, HDR monitoring points, and multiple distribution targets. HLG is often easier to move through that environment because it doesn't depend on HDR10-style static metadata and is more forgiving when every display isn't a calibrated mastering monitor. HLG is common for:

Live HDR broadcast production
Sports and event television
Broadcast contribution and programme exchange
Camera-originated HDR workflows where speed matters
Productions that need an HDR signal with more tolerance for some SDR viewing paths than PQ

That last phrase needs care. People often describe HLG as more SDR compatible, but that doesn't mean “HLG is SDR.” It means an HLG signal can often produce a more acceptable image on some non-HDR or SDR-ish paths than PQ would. If you view PQ incorrectly on an SDR display, it often looks very wrong because the display interprets absolute HDR code values through the wrong curve. HLG can fail more gracefully, but it still needs color management, monitoring, and proper conversion for a real SDR master. For HLG monitoring, the viewing environment matters more than many teams expect. Because the final appearance depends on display peak luminance and system gamma, two HLG monitors can look different if they're set for different target luminance values or rooms. EBU guidance exists specifically because broadcasters need common reference modes for HLG monitors across different peak luminance capabilities and viewing environments. The takeaway: HLG can be more flexible, but flexibility isn't the same as consistency. If multiple teams are reviewing HLG, your team should define the monitor mode and environment, not just “Rec.2100 HLG.”

The same HLG signal may render differently on different displays.

How the wrong monitor mode shows up

Most HDR monitoring problems aren't subtle once you know what caused them. The same file can look “cinematic” in one room, flat in another, and radioactive on a client display because something in the chain interpreted the transfer function incorrectly. Common failure modes include:

Your team monitors a PQ signal as HLG: highlights and midtones don't appear at the expected brightness levels, and the image may look oddly compressed or lifted.
Your team monitors an HLG signal as PQ: the picture can look too dark or incorrectly weighted because the monitor expects absolute PQ luminance values.
Your team monitors an HDR signal through an SDR path: highlights clip, midtones shift, or the image appears washed out depending on the transform.
Your team sets the timeline to one HDR format while the output device is set to another: scopes may seem reasonable while the display lies.
Your team leaves a consumer TV in a dynamic tone-mapping mode during approval: the client is approving the TV’s interpretation, not the master.

Calibration matters, but the fix is to make the whole viewing chain explicit: timeline color space, output transform, video I/O format, monitor mode, peak luminance behavior, metadata behavior, and room conditions.

Reliable HDR monitoring depends on the whole viewing chain agreeing.

Delivery format usually decides the monitoring format

For finishing, the delivery spec should drive the monitoring path. If the spec says HDR10, monitor PQ. If the spec says Dolby Vision, monitor the PQ base layer and the Dolby Vision trims using the required analysis and display targets. If the spec says HLG for broadcast, monitor HLG using the broadcaster’s reference settings. A useful way to separate the choices is by delivery family:

HDR10: PQ, usually with static metadata such as mastering display information and MaxCLL/MaxFALL.
HDR10+: PQ, with dynamic metadata.
Dolby Vision: PQ-based HDR mastering with dynamic metadata and trims for target displays.
UHD Blu-ray HDR: PQ-based delivery.
Many streaming HDR masters: PQ-based delivery.
Broadcast HDR, especially live: often HLG, depending on network and regional requirements.
Fast-turnaround HDR television: often HLG when the pipeline is designed around broadcast compatibility.

You can still convert, and PQ-to-HLG and HLG-to-PQ conversions are normal in real workflows. ITU guidance describes conversion methods, and MovieLabs guidance notes that studios generally master film and TV HDR in PQ, then create HLG versions when needed for distribution and subject to content provider approval. The key word is approved. A conversion changes how brightness relationships are rendered. If you create an HLG version from a PQ master, your team needs to review the HLG result on a proper HLG monitor. If you create a PQ version from HLG production, your team needs to decide how diffuse white, highlights, and clipping should map into the PQ master.

Monitor setup choices that actually matter

In a real room, “HDR monitor” is incomplete information. A display can support HDR and still be in the wrong mode for your signal. A consumer TV can show an HDR badge and still apply tone mapping, dynamic contrast, local dimming behavior, or color enhancement that makes it unsuitable for final approval. For PQ review, define these parameters clearly:

Transfer function: PQ / ST 2084
Colorimetry: Rec.2100 / Rec.2020 container, with the expected working gamut
Mastering peak target: commonly 1000 nits, or another spec-defined target
Monitor behavior above peak: clip, roll off, or tone map
Range handling: narrow/video range unless your pipeline explicitly supports full range end to end
Metadata handling: whether the monitor reads HDR metadata or your team manually forces it into the reference mode

Those settings determine whether PQ review is acting as a fixed reference or a display-dependent preview. For HLG review, define a slightly different set:

Transfer function: HLG
Colorimetry: Rec.2100 / Rec.2020 container
Target monitor peak luminance or broadcaster-defined HLG mode
Viewing environment assumptions
System gamma or monitor preset your team uses for that environment
SDR conversion path, if SDR deliverables are also required

The detail that often saves a session is forcing the monitor into the intended mode instead of trusting auto-detect. Auto-detect can be useful, but it depends on metadata, SDI/HDMI signaling, operating system behavior, and device support. In a finishing room, manual confirmation beats assumptions.

Scopes are necessary, but they don't replace the display

HDR scopes help you see signal levels, clipping, gamut excursions, and transform mistakes. They're especially important when moving between PQ and HLG because the same visual area of the image may sit at very different signal values depending on the transfer function. For PQ, scopes are useful because luminance values connect directly to displayed light. You can inspect where diffuse white sits, where highlights peak, and whether the grade exceeds the intended mastering target. For HDR10 deliverables, signal analysis also supports metadata decisions like MaxCLL and MaxFALL, although your team shouldn't treat those values as creative controls. For HLG, scopes help confirm legal range, relative highlight behavior, and conversion consistency. Since HLG adapts at display, the scope doesn't tell the whole perceptual story, but it can catch obvious pipeline errors before they waste review time. Use scopes and a reference display together. If the scopes say your PQ highlight peaks are controlled but the display clips ugly, your monitor behavior or target may be wrong. If the display looks fine but the scopes show illegal levels or color outside the permitted gamut, the file may still fail delivery QC.

Mixed SDR, PQ, and HLG timelines need a declared intent

Many editorial teams hit HDR confusion before finishing. A camera clip may be tagged HLG. A stock shot may be PQ HDR10. Graphics may be Rec.709. Proxies may be SDR. The NLE may auto-detect some clips and silently tone map others. This is where teams lose hours because everyone is looking at a different transform. In editorial, the question is “what is this sequence supposed to represent?” If the show will finish as PQ, the editorial viewing transform should support a PQ-aware path or a controlled SDR viewing approximation. If the show will finish as HLG, the timeline should preserve HLG correctly or convert sources into the agreed working space. If editorial is SDR only, your team needs an intentional tone map for HDR sources so they don't appear overexposed, flat, or mismatched. For assistants and post supervisors, the useful metadata to track is simple:

Source color space and transfer function
Timeline or sequence color space
Monitoring transform used for offline review
Proxy color handling
Intended HDR finishing format
Any LUTs or color management transforms your team baked into editorial media

That information prevents the classic conform problem where the colorist receives a timeline that looked acceptable in editorial only because the NLE or OS was applying a hidden transform.

When PQ is the better monitoring choice

Choose PQ monitoring when the creative intent depends on controlled absolute luminance. This is usually the case for scripted, commercial, feature, episodic, premium streaming, Dolby Vision, HDR10, and UHD Blu-ray work. PQ is also the safer choice when your team will derive multiple downstream versions from one approved HDR master. If the PQ master is the hero version, you can create SDR trims, HLG conversions, and alternate deliverables from a known source of truth. That doesn't make the conversions automatic, but it gives everyone a stable reference. PQ is the wrong choice only when the delivery path doesn't want it, the production pipeline can't support it, or the monitoring environment isn't capable of showing the intended result. A “PQ” grade on an untrusted display can be worse than a well-managed HLG workflow because PQ’s strength is precision. If the reference isn't actually precise, the confidence is fake.

When HLG is the better monitoring choice

Choose HLG monitoring when the production and delivery environment benefits from relative rendering and broadcast-friendly behavior. Live sports, events, news, music broadcasts, and fast-turnaround television are the obvious cases. HLG can simplify parts of the chain because it doesn't require the same metadata-driven display behavior as PQ HDR10. HLG can also be useful when HDR and SDR workflows need to coexist during production, although your team still needs a proper conversion for a dedicated SDR output. Don't assume an HLG master automatically satisfies SDR delivery. It may look acceptable in some places, but your team still needs to review proper SDR delivery for contrast, saturation, graphics, and highlights. HLG is the wrong choice when the spec asks for PQ, when the project needs Dolby Vision or HDR10 mastering, or when the creative team is making fine luminance decisions that must appear consistently across calibrated mastering displays.

The decision to make before you book the room

Decide the monitoring format from the delivery path, then build the room around that decision. PQ and HLG are both valid HDR systems, but they aren't interchangeable monitor presets. PQ gives you absolute luminance control for mastered HDR. HLG gives you relative rendering flexibility for broadcast and mixed display environments. For a clean workflow, name the format in every handoff: Rec.2100 PQ or Rec.2100 HLG, not just “HDR.” Confirm that the NLE, color system, I/O hardware, scopes, and display are all interpreting the same signal. If you need both PQ and HLG, pick the hero master, define the conversion, and review the converted version on its own terms. Without that confirmation, the HDR badge on the display isn't enough to prove the chain is correct.

FAQ

Neither is universally better. PQ is usually better for mastering and approval when absolute luminance matters, such as HDR10, HDR10+, Dolby Vision, UHD Blu-ray, and premium streaming deliverables. HLG is usually better for live broadcast, fast-turnaround television, and workflows where the HDR signal must adapt across different display capabilities.

PQ uses an absolute transfer function, SMPTE ST 2084, where signal values correspond to specific display luminance levels. If a display interprets PQ as SDR or HLG, it applies the wrong brightness relationship, which can make the image look too dark, washed out, clipped, or incorrectly weighted in the midtones and highlights.

No. HLG can be more tolerant than PQ in some SDR-adjacent viewing paths, but it isn't the same as a finished SDR master. A proper SDR deliverable still needs an intentional conversion and review for contrast, saturation, graphics, skin tone, and highlight handling.

HLG is a relative HDR system, so the final displayed image depends on the monitor’s peak luminance, black level, system gamma, preset, and viewing environment. Two displays can both be using HLG correctly but still render brightness relationships differently if they're configured for different reference conditions.

Yes, PQ-to-HLG and HLG-to-PQ conversions are common, but they should be treated as creative and technical transforms, not simple file exports. The converted version should be reviewed on a properly configured monitor using the target transfer function, because highlight mapping, diffuse white, contrast, and clipping behavior can change.

Treat the transfer function as production metadata, not tribal knowledge. Aspect lets teams add custom fields for items like Rec.2100 PQ, Rec.2100 HLG, SDR transform, monitor target, and delivery version, so assistants and supervisors can keep those details attached to the media with custom metadata.