Why It Looks Like That
Article 17

TV Black Level: How to Preserve Shadow Detail Without Raising Blacks

Match the source and television quantization ranges first, then use the correct SDR, PQ, or HLG PLUGE pattern to preserve near-black detail without lifting reference black.

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Direct answer

In brief

Set black level in two stages. First, match the source and television quantization ranges so they interpret reference black and white from the same digital endpoints. Then use a valid SDR, PQ, or HLG PLUGE pattern and adjust the black-level lift so the slightly darker stripe disappears while the slightly lighter stripe remains visible. A correct threshold does not prove perfect near-black reproduction, which still depends on EOTF tracking, panel behavior, processing, source quality, and room reflections.

Watch a dark scene.

The picture may contain:

A correctly set television should preserve the distinctions that are present in the source and that the display can reproduce under the viewing conditions.

It should not reveal detail that the program intentionally places at black.

It should not turn near-black texture into one flat patch.

It should not lift black into gray.

The practical setup has two stages:

  1. Make sure the source and television use the same quantization range.
  2. Use a valid PLUGE pattern to set the display’s black-level threshold.

Do not use the black-level lift control to hide a range mismatch.

Do not assume that SDR black is always code 16 or that HDR black is always code 0.

The code depends on the signal representation.

Black level has more than one meaning

The phrase black level can refer to several related things.

Signal black

The digital or normalized signal value that represents reference black.

Display black luminance

The light emitted or reflected from the screen when reference black is displayed.

Black-level lift control

The user control that moves the lower part of the display response.

It has traditionally been labeled Brightness.

Quantization range

The mapping between digital codes and nominal black and white.

Perceived black

The black seen by the viewer after screen reflection, room light, adaptation, and display behavior are included.

These are connected.

They are not identical.

A five-stage chain separates signal black, quantization range, the television black-level lift control, emitted screen black, and perceived black after room reflection and viewing conditions. The stages are related but are not interchangeable.
Black level can mean a signal code, a range mapping, a display control, emitted light, or the black the viewer sees.

Black level is not the entire shadow region

A PLUGE adjustment establishes the transition around reference black.

It does not prove that every dark gray is reproduced correctly.

The remaining shadow region depends on:

Think of PLUGE as setting the starting line.

The near-black grayscale is the race that follows.

Digital code values

SDR narrow range

Recommendation ITU-R BT.709-6 defines these nominal luma or RGB endpoints:

8-bit narrow range

10-bit narrow range

For chroma in narrow-range Y′CbCr:

This is why saying “video is 16 to 235” is a useful shorthand for luma or limited RGB, not a complete description of every component.

Video-data excursions

BT.709 does not define every code below 16 or above 235 as unusable.

For 8-bit coding it assigns:

The nominal picture range is still black 16 to white 235.

Codes outside those nominal endpoints can carry:

A system may clip them.

A system may preserve them.

The workflow should state which behavior is intended.

SDR full range

Full-range RGB commonly maps:

Sony professional-monitor documentation and NVIDIA output documentation provide current implementation examples of those ranges. [8][9]

A full-range signal does not produce deeper black than a correctly decoded narrow-range signal.

Both can map reference black to the display’s black.

The difference is how the digital codes are allocated and signaled.

Two eight-bit signal bars compare narrow range, with nominal black at code 16 and nominal white at 235, with full range, with black at 0 and white at 255. Both are mapped to the same displayed black and white endpoints when the source and display interpretations match. Narrow-range excursions are shown outside the nominal picture interval.
Correctly decoded narrow and full representations can reach the same displayed black and white endpoints.

HDR code values

BT.2100 defines narrow and full representations

Recommendation ITU-R BT.2100-3 defines digital representations for PQ and HLG.

It says that:

That statement is about the recommendation’s exchange scope.

It does not prohibit a supported full-range consumer or production path.

Ten-bit HDR narrow range

For PQ or HLG narrow range:

Values can extend beyond the nominal interval within the permitted video-data range.

The exact meaning of 100 percent differs between PQ and HLG.

The digital endpoints can still be the same.

A four-row standards table shows SDR narrow, PQ narrow, and HLG narrow with black at code 64 and nominal endpoint at code 940, and PQ full range with black at code 0 and full scale at 1023. A qualification states that identical integer endpoints do not make SDR, PQ, and HLG transfer systems identical.
SDR narrow, PQ narrow, and HLG narrow can share ten-bit endpoints without sharing one transfer function.

Ten-bit PQ full range

For PQ full range:

This is the case in which the original statement “HDR black is code 0” applies.

It does not apply to narrow-range HDR.

Twelve-bit values

In the ITU narrow-range representations:

In full range:

The reader does not need to memorize all of these numbers.

The important lesson is:

Bit depth and quantization range both determine the integer code for black.

PQ zero is not always digital code zero

PQ defines a normalized signal relationship.

At normalized PQ input zero, the reference EOTF output is zero luminance.

In narrow-range integer coding, that normalized zero point is offset to code 64 at 10 bits.

The chain is:

  1. integer code 64
  2. converted to normalized PQ value 0
  3. PQ EOTF produces reference black

Confusing normalized values with integer codes causes incorrect HDR setup advice.

A four-stage flow shows ten-bit narrow-range integer code 64, removal of the narrow-range offset and scale, normalized PQ signal value zero, and zero reference luminance under the PQ EOTF. A parallel note shows that ten-bit full-range PQ uses integer code 0 for normalized zero.
Ten-bit narrow-range PQ carries normalized zero at integer code 64, while full-range PQ carries it at code 0.

HLG is different

HLG is a relative HDR system.

Its narrow-range black is also code 64 at 10 bits.

The final output near black depends on:

ITU-R BT.2100-3 says that black level should be adjusted with a PLUGE signal for HLG in any viewing environment. [2][5]

A HLG setup should not be treated as a PQ setup with different metadata.

Narrow and full range

Narrow range does not mean washed-out black

A correctly decoded narrow-range signal maps:

A correctly decoded full-range signal maps:

The visible endpoints can be the same.

A range mismatch, not narrow range itself, creates gray black or clipped shadows.

Range is not the same as color format

These combinations can exist:

Sony’s professional-monitor manual provides selectable RGB and YCC full or limited examples over HDMI. [8]

Do not use:

as universal rules.

A two-by-two matrix shows RGB narrow, RGB full, YCbCr narrow, and YCbCr full where supported. A note states that RGB does not always mean full and YCbCr does not always mean narrow. The exact permitted combinations depend on the system and device.
RGB and YCbCr describe component formats; quantization range is a separate property that must be verified.

Match the actual source

The source and display must agree about:

A range setting can be called:

Names do not map consistently across brands.

Use the manual and a pattern.

Range mismatches

Top panel shows a narrow-range source interpreted as full range, placing code 16 above expected black and code 235 below expected white, which can raise black and compress contrast. Bottom panel shows a full-range source interpreted as narrow range, clipping values below 16 and above 235, which can crush shadows and clip highlights.
A narrow-to-full mismatch raises black and compresses contrast, while a full-to-narrow mismatch clips both ends.

Narrow source interpreted as full

Consider 8-bit narrow-range RGB or luma.

The source uses:

If the display expects:

then code 16 is above the expected black endpoint.

The result can include:

Changing the display’s black-lift control can hide part of the symptom.

It does not restore the correct mapping.

Full source interpreted as narrow

Now consider 8-bit full range:

If the display expects narrow range:

The result can include:

The correct fix is range matching.

A mismatch can be partial or conditional

The failure can appear only in:

A device may switch between RGB and Y′CbCr according to bandwidth.

It may also change quantization signaling.

Test the state that is actually used.

Use Auto first when it works

Many systems negotiate or signal quantization range.

Official PlayStation documentation says its PS5 RGB Range option should be changed only when an HDMI device does not communicate range information correctly. [10]

That is a sensible general diagnostic sequence:

  1. Start with Auto on both devices.
  2. Display a valid black and white range pattern.
  3. Confirm the result.
  4. Override manually only when Auto is wrong or the path does not signal correctly.
  5. Record the manual choice.

Manual is not inherently more accurate.

Computer output

NVIDIA’s official documentation offers:

for RGB output and warns that forcing full range to a display that does not support it can produce incorrect color. [9]

A computer connected to a television can use either range when both ends match.

Full RGB is often appropriate for a desktop workflow.

It is not mandatory for every video application or HDMI chain.

Internal applications

An internal television application does not pass through an external HDMI RGB-range menu.

It can still have separate:

Do not use an HDMI range control to diagnose an internal app unless the manufacturer says the control applies.

Input labels

A PC input label can alter:

It can also make some controls unavailable.

Test the label.

Do not apply it only because the source device has a computer-like name.

Which control sets black level?

Two-panel comparison. A range control changes how digital endpoints are interpreted, such as 16 to 235 versus 0 to 255. A black-level lift control changes the display response around reference black after the range is matched. The exact menu labels vary by manufacturer.
A range control selects endpoint interpretation, while a black-lift control adjusts the display threshold around black.

Legacy Brightness

ITU-R BT.814-4 calls the adjustment the user black level lift control and identifies Brightness as the legacy name. [3]

Spears & Munsil explains that moving this control can shift the handled brightness range, not only one digital code. [7]

On a traditional consumer television, this is the control used with PLUGE.

Modern naming conflicts

A control named Brightness can instead change:

A control named Black Level can instead change:

A control named Shadow Detail may alter:

Do not adjust a control until its function is identified.

How to identify the black-lift control

Use the manual and a PLUGE pattern.

A black-lift control should primarily change the threshold around black.

A panel-light control should change much of the image or the display’s output capability.

A range control should switch the interpretation of digital endpoints.

A local-dimming control should change spatial contrast behavior.

Record which one is being changed.

PLUGE

A simplified standards-based PLUGE schematic shows a reference-black background, a slightly darker stripe, and a slightly lighter stripe. The darker stripe is labeled hidden at the correct black-level setting and the lighter stripe is labeled visible. The drawing is not the full ITU pattern geometry.
Set PLUGE so the darker stripe disappears while the lighter stripe remains visible under the intended viewing conditions.

What PLUGE means

PLUGE stands for Picture Line-Up Generation Equipment.

The term refers to test signals used to align black level and related display behavior.

Recommendation ITU-R BT.814-4 specifies PLUGE signals and procedures for:

ITU PLUGE levels

The HDTV, UHDTV, and HDR pattern contains:

The exact geometry is less important to the home reader than using the correct pattern documentation.

SDR ITU values

For SDR narrow range:

8 bit

10 bit

HDR ITU values

For HDR narrow range:

10 bit

12 bit

The higher-level patch is used differently in the HDR setup procedure.

Do not treat it as peak white.

A three-row table lists slightly darker, reference black, and slightly lighter code values. Eight-bit SDR uses 12, 16, and 20. Ten-bit SDR narrow uses 48, 64, and 80. Ten-bit PQ or HLG narrow also uses 48, 64, and 80. A note states that matching code values do not make SDR, PQ, and HLG procedures identical.
Use the code values and procedure documented for the exact SDR, PQ, or HLG pattern.

BT.2111 HDR patterns

Recommendation ITU-R BT.2111-3 provides current HDR color-bar patterns for:

It explicitly says the color-bar pattern is not intended for black-level adjustment and that PLUGE is preferred. [4]

It also confirms near-black code examples.

For 10-bit narrow-range PQ or HLG:

Spears & Munsil PLUGE

The Spears & Munsil technical notes describe a pattern with:

Its documented procedure is:

Different pattern design.

Same threshold principle.

Setting black level by eye

Before the adjustment

Confirm:

Allow the display and viewing condition to stabilize according to the workflow.

SDR procedure

ITU-R BT.814-4 says the SDR adjustment depends strongly on viewing conditions.

Its procedure is:

  1. Set the display’s white or gain level to the desired luminance.
  2. Adjust the black-level lift so the blackest stripe just disappears.
  3. Keep the brighter stripe visible. [3]

For the ITU SDR pattern, that means:

Do not substitute code 17 for code 20 when using the ITU pattern.

Follow the pattern in use.

Practical visual sequence

  1. Lower the black-level lift until the positive stripe disappears.
  2. Raise it slowly until the positive stripe is visible.
  3. Confirm that the negative stripe remains merged with black.
  4. Move one step in each direction to understand the control resolution.
  5. Select the setting that preserves the positive stripe without revealing the negative stripe.
  6. Recheck after white-level adjustment.

The positive stripe can be faint.

It should be repeatably visible from the normal seat under the intended room condition.

HDR procedure

BT.814 gives separate HDR instructions.

HLG

The procedure includes:

  1. set the appropriate HLG system gamma for nominal peak and viewing environment
  2. set black lift to zero initially
  3. set the higher-level patch to the specified luminance using the gain control
  4. adjust system gamma further when needed for a non-reference environment
  5. adjust black-level lift so the darker stripe disappears and lighter stripe remains [3]

A consumer television may not expose those controls separately.

Use the manufacturer’s intended HLG mode and test the available black control.

PQ

BT.814 says a user gain control is not required for PQ because display luminance is determined by the PQ EOTF, although maximum output depends on the display capability. [3]

For the black threshold:

A consumer PQ mode may fix black level correctly at the default.

Do not change it merely because the menu offers a control.

Do not chase visibility in total darkness only

Near-black visibility changes with:

Set the control for the viewing condition established in Article 14.

A value chosen after prolonged dark adaptation can reveal signal structure that is not useful or stable during normal viewing.

One control step can be coarse

Some televisions provide a control with large steps.

There may be no setting where:

Spears & Munsil advises that when a perfect setting is not available, preserving picture information can be preferable to cutting it off. [6]

Document the compromise.

A meter and near-black sweep can help.

Valid pattern delivery

An example external calibration path runs from pattern file through player, operating system or application, AVR or soundbar, HDMI conversion, and television. Possible changes below the path include quantization range, RGB or YCbCr format, scaling, HDR conversion, and compression. The path is an example, not a universal device chain.
A calibration pattern is only trustworthy when its complete playback path preserves the intended signal.

Use the path being calibrated

To calibrate:

One path does not prove another.

What can alter the pattern

The pattern can be changed by:

A correct-looking file is not enough.

The output signal must be correct.

Disc and downloaded files

A purpose-built calibration disc or officially documented lossless test file is usually a better controlled source than a platform video.

The source still needs correct:

A disc is not immune to device conversion.

Streaming video

A streaming service can alter:

Use streaming patterns for education or rough diagnosis unless the complete delivery path has been verified.

Do not call a pattern accurate only because the uploader is knowledgeable.

USB playback

USB playback can use a different decoder from HDMI or an internal app.

It can change:

Verify the television’s USB path separately.

Service menus

Do not enter a service menu for basic PLUGE setup.

The user menu and an external supported pattern are sufficient for normal adjustment.

Service-menu changes can have broad and undocumented effects.

What correct black level looks like

In the pattern

Under the intended conditions:

In real content

A correct threshold should allow:

It does not mean every dark room in a film must be visible.

The source can intentionally place detail:

Letterbox bars

Letterbox bars are often encoded near black.

They can also be:

They are useful as a clue.

They are not a substitute for PLUGE.

OLED

An OLED can produce very low emitted black and can turn pixels off for supported black signals.

The viewed result can still appear raised because of:

Do not lower black lift until detail disappears merely to make the screen look powered off.

A conceptual optical diagram shows a black screen pixel with low emitted light, room light striking the screen, reflected light traveling to the viewer, and the combined viewed black. It explains why a screen can emit very little light yet look raised in a bright or reflective room.
Viewed black includes both screen emission and room light reflected toward the viewer.

LCD and local dimming

An LCD’s viewed black can depend on:

A PLUGE pattern can interact with local dimming.

Test:

Do not turn local dimming off automatically.

Use the model’s best reference-oriented setting.

Two conceptual paths compare OLED and locally dimmed LCD near black. OLED includes per-pixel emission, near-black temporal drive or compensation, and screen reflection. LCD includes backlight or local-dimming output, panel transmission, viewing angle, and reflection. Neither path is labeled universally superior or perfectly accurate.
OLED and LCD can reach near black through different physical and processing paths, so their limitations should be tested differently.

Projection

A projector’s black depends strongly on:

The same PLUGE principle applies.

The darkest visible level may be limited by the room and system rather than one electronic offset.

Troubleshooting

Blacks are gray

Check, in this order:

  1. direct light and screen reflection
  2. source and display range match
  3. black-level lift control
  4. adaptive brightness
  5. dynamic contrast or black enhancement
  6. source master
  7. internal app versus HDMI path
  8. local-dimming state
  9. EOTF or gamma
  10. panel limitation

Do not assume the range is wrong before testing it.

Shadows are crushed

Check:

  1. full source interpreted as narrow
  2. black-lift control too low
  3. contrast enhancer or black enhancer
  4. local dimming
  5. incorrect picture mode
  6. near-black EOTF
  7. noise reduction
  8. compression
  9. source mastering
  10. panel limitation

Pattern works, content looks wrong

Possible causes include:

Do not recalibrate from one difficult scene.

SDR is correct, HDR is wrong

Verify:

SDR values cannot simply be copied into HDR.

One HDMI device is wrong

Check:

Computer desktop is wrong but video is correct

The operating system or video application can use separate paths.

Check:

Measurement beyond PLUGE

Left panel shows a single black threshold with a darker stripe hidden and a lighter stripe visible. Right panel shows a conceptual multi-step near-black grayscale rising through several code levels toward an EOTF curve. The figure states that PLUGE does not certify grayscale neutrality, monotonicity, EOTF tracking, or temporal behavior.
PLUGE aligns the black threshold, but it does not verify the entire near-black grayscale or EOTF.

Near-black grayscale sweep

A meter can evaluate several low signal levels rather than one positive stripe.

Useful questions include:

Signal analyzer

A signal analyzer or waveform monitor can confirm whether the source outputs:

This separates source failure from display failure.

Meter limitations near black

Near-black luminance can challenge a meter because of:

A visual PLUGE check remains useful.

Measurement conditions must be recorded.

Pattern size and duration

A pattern can interact with:

Record:

What calibration can fix

Within the display’s controls, calibration can reduce errors in:

It can identify the best available compromise.

What calibration cannot fix

Calibration cannot:

For a reader using a valid pattern:

  1. Select the intended SDR or HDR mode.
  2. Reset the mode if prior changes are unknown.
  3. Disable optional contrast and adaptive controls.
  4. Confirm source and display range are Auto or matched.
  5. Display the correct SDR, PQ, or HLG PLUGE.
  6. Lower black lift until the positive stripe disappears.
  7. Raise it until the positive stripe remains visible.
  8. Confirm the negative stripe is hidden.
  9. Check a real dark scene.
  10. Save and document the setting.
  11. Recheck after white-level adjustment.

Five minutes can set the threshold.

A complete near-black calibration takes longer.

Eight-step workflow: select the intended mode, control optional processing, match source and display range, load the correct SDR, PQ, or HLG PLUGE, hide the negative or darker stripe, keep the positive or lighter stripe visible, check a real dark scene, and record the result. A final note says to recheck after white-level adjustment.
Match the range, use the correct PLUGE, preserve the positive stripe, check real content, and document the result.

Where this leaves us

Black level is not one universal code value and not one universal menu control.

For common narrow-range SDR:

For narrow-range PQ and HLG:

For full range:

The source and display must agree.

Once the range is correct, PLUGE establishes the visible threshold.

The ITU procedure is simple:

That procedure must use:

A correct PLUGE result preserves the beginning of shadow detail.

It does not prove that every near-black tone is perfect.

The next step is white level.

Black level sets where the tonal range begins.

White level determines how the upper range is handled before clipping and display limits take over.

Sources and standards

Primary ITU signal-range and PLUGE recommendations, calibration-pattern guidance, and manufacturer range documentation used in this article. Last verified August 6, 2026.

  1. International Telecommunication Union Radiocommunication Sector. Parameter Values for the HDTV Standards for Production and International Programme Exchange. Recommendation ITU-R BT.709-6, June 2015.
    https://www.itu.int/dms_pubrec/itu-r/rec/bt/r-rec-bt.709-6-201506-i%21%21pdf-e.pdf

    ↩↩↩

  2. International Telecommunication Union Radiocommunication Sector. Image Parameter Values for High Dynamic Range Television for Use in Production and International Programme Exchange. Recommendation ITU-R BT.2100-3, February 2025.
    https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.2100-3-202502-I%21%21PDF-E.pdf

    ↩↩↩↩

  3. International Telecommunication Union Radiocommunication Sector. Specifications of PLUGE Test Signals and Alignment Procedures for Setting of Brightness and Contrast of Displays. Recommendation ITU-R BT.814-4, July 2018.
    https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.814-4-201807-I%21%21PDF-E.pdf

    ↩↩↩↩↩↩↩↩

  4. International Telecommunication Union Radiocommunication Sector. Specification of Colour Bar Test Pattern for High Dynamic Range Television Systems. Recommendation ITU-R BT.2111-3, May 2025.
    https://www.itu.int/dms_pubrec/itu-r/rec/bt/R-REC-BT.2111-3-202505-I%21%21PDF-E.pdf

    ↩↩↩↩↩

  5. International Telecommunication Union Radiocommunication Sector. Guidelines for operational practices in high dynamic range television production. Report ITU-R BT.2408-9, March 2026.
    https://www.itu.int/pub/R-REP-BT.2408-9-2026

    ↩

  6. Spears & Munsil. Technical Notes on the Patterns. Official calibration documentation, reviewed July 31, 2026.
    https://spearsandmunsil.com/portfolio-item/technical-notes-on-the-patterns/

    ↩↩

  7. Spears & Munsil. Setting the Brightness Control, Ultra HD Edition. Official calibration documentation, reviewed July 31, 2026.
    https://spearsandmunsil.com/portfolio-item/setting-the-brightness-control-3/

    ↩

  8. Sony Corporation. BVM-E251/BVM-E171 Professional Video Monitor Operating Instructions. Public manual, reviewed July 31, 2026.
    https://www.sony.com/electronics/support/res/manuals/4688/ed695ff16fdc232898271d0a3c85c6bd/46886451M.pdf

    ↩↩↩

  9. NVIDIA Corporation. To Change the RGB Dynamic Range. Official control-panel documentation, reviewed July 31, 2026.
    https://www.nvidia.com/content/Control-Panel-Help/vLatest/en-us/mergedProjects/nvdsp/To_change_the_RGB_range.htm

    ↩↩

  10. Sony Interactive Entertainment. How to Change PS5 Console Resolution. Official support documentation, reviewed July 31, 2026.
    https://www.playstation.com/en-us/support/hardware/ps5-4k-resolution-guide/

    ↩

  11. International Telecommunication Union Radiocommunication Sector. A Reference Viewing Environment for Evaluation of HDTV Program Material or Completed Programmes. Recommendation ITU-R BT.2035-0, July 2013.
    https://www.itu.int/rec/R-REC-BT.2035-0-201307-I

  12. Samsung Electronics. How to Adjust the Picture Quality for Each Picture Mode in Samsung Smart TV? Updated July 30, 2024, reviewed August 6, 2026.
    https://www.samsung.com/in/support/tv-audio-video/how-to-adjust-the-picture-quality-for-each-picture-mode-in-samsung-smart-tv/

Related reading: TV Test Patterns: What They Show and How to Use Them Use PLUGE and related patterns to check range matching and near-black detail. Next step: Set White Level and Peak Brightness Continue from black-level threshold and range matching into SDR nominal white, reference luminance, RGB clipping, HDR Reference White, peak output, and brightness limiting.