TV Calibration Glossary: SDR, HDR, Gamma, Color Temperature, and Picture Settings

How to use this glossary

Each entry gives the practical meaning first, then identifies an important limit or condition. Links lead to the full article when a term needs more explanation. Formal definitions are grounded in the listed standards and official technical sources. Manufacturer terms are described as implementation-dependent rather than universal.

Jump to: A-C · D-G · H-N · O-R · S-Z and numbers

A-C

Absolute luminance

Light output expressed on a physical scale, normally candelas per square metre (cd/m²), also called nits. The PQ reference EOTF assigns absolute luminance values to signal values, while common SDR gamma descriptions are relative to the selected black and white levels. ^[1]

Accuracy

The degree to which a display reproduces a declared target under stated conditions. Accuracy is not a single permanent label for a television. It depends on the signal format, picture mode, room, measurement system, pattern, display state, and the properties being evaluated.

Automatic brightness limiting (ABL)

A common descriptive term for reductions in display light output caused by power, thermal, panel, or product-control limits. The trigger, speed, affected picture area, and recovery behavior vary by display. ABL is not one standardized algorithm.

Average picture level (APL)

A common shorthand for the average signal level or average brightness of a frame or test pattern. APL can affect the measured output of displays with power or thermal limiting, but the term does not by itself specify pattern geometry, duration, or measured luminance.

Automated calibration / AutoCal

A software-guided workflow that can write supported adjustments or lookup tables into a compatible display. The name is vendor-specific. It does not remove the need to validate the meter, correction, pattern source, signal path, target, and final result.

Banding

Visible steps or stripes in what should be a smooth gradient. Banding can come from limited source precision, compression, processing, conversion, display behavior, or a combination of them. A higher nominal bit depth helps preserve precision but does not guarantee a band-free image.

Bias lighting

Controlled light placed behind or around the television without shining onto the screen. It can reduce visual fatigue and provide a stable surround. Its spectrum, level, placement, wall color, and room reflections affect the result.

Bit depth

The number of binary digits assigned to a component sample. An ideal unsigned n-bit component has 2ⁿ possible code values before range restrictions or reserved values are considered. See 10-bit video and banding.

Black clipping / black crush

A condition in which different dark signal values are rendered as the same black or become visually indistinguishable. It can be caused by a range mismatch, an incorrect black-level control, processing, display limits, or the source itself.

Black level

The displayed threshold associated with reference black and values just above it. A menu control named Brightness may adjust black level on one television and panel output on another. See black level and HDMI range.

Blooming

Visible light spreading around a bright object because an LCD backlight zone illuminates a larger area than the object. Zone size, local-dimming logic, viewing angle, room conditions, and content all affect its visibility. Self-emissive displays do not have backlight-zone blooming, though other halos or glare may still be visible.

Brightness

An ambiguous television menu label. Depending on the model and mode, it may adjust the black threshold, overall panel light output, a signal offset, or another function. Confirm the manual and observe or measure the control before changing it.

BT.1886

An ITU-R reference electro-optical transfer function for flat-panel displays used in HDTV studio production. It derives the display response from the measured black and white luminance, so it is not simply identical to a pure 2.4 power function in every case. See gamma and BT.1886 setup. ^[2]

BT.709 / Rec. 709

An ITU-R recommendation defining HDTV system parameters, including RGB primary chromaticities, the D65 reference white, and signal characteristics. In consumer discussion, “Rec. 709” often refers mainly to the SDR HDTV colorimetry, but the recommendation covers more than a gamut triangle. See color gamut and the CIE diagram. ^[3]

BT.2020 / Rec. 2020

An ITU-R recommendation defining UHD television system parameters, including a wide set of RGB primary chromaticities. BT.2020 is often used for HDR signaling, but the recommendation is not itself an HDR transfer function, and a consumer display need not reproduce the full BT.2020 gamut. ^[4]

BT.2100

An ITU-R recommendation defining two HDR television systems, PQ and HLG, within BT.2020 colorimetry and with D65 as the reference white. It applies to production and international programme exchange, not to one universal consumer menu layout. See PQ and HLG. ^[5]

Calibration

A measured process that compares a display with declared targets, makes supported adjustments, and verifies the result. Pattern-based setup without measurements can still be useful, but it should not be described as measured calibration. See the calibration workflow.

Chroma

Color-difference information carried separately from luma in component video systems. Chroma does not mean the same thing as all color appearance, and reducing chroma sampling does not reduce the luma sampling grid.

Chroma subsampling

A sampling structure that carries luma at a higher spatial sampling rate than the color-difference components. Labels such as 4:4:4, 4:2:2, and 4:2:0 describe component sampling relationships, not bit depth or compression quality. See chroma subsampling.

Chromaticity

A description of color independent of luminance, commonly represented by coordinates such as CIE x and y or u′ and v′. A chromaticity diagram is two-dimensional, so it does not show brightness or full color volume. ^[6]

Clipping

Loss of distinction because multiple input values are forced to the same output limit. Clipping can occur near black, near white, in individual RGB channels, or after color and luminance mapping. A flat-looking highlight is not proof of clipping unless the source and signal steps are known.

Code value

A numerical sample value carried by a digital video component. Its meaning depends on bit depth, range, transfer function, color encoding, and format. The same number can represent different light levels or colors in different systems.

Color gamut

The set of chromaticities a system or display can represent under defined conditions. An RGB triangle on a chromaticity diagram is a two-dimensional gamut boundary. It does not show luminance, tone response, or the full three-dimensional color volume. ^[6]

Color management system (CMS)

A group of display controls intended to adjust color properties, often for primary and secondary colors. Control names and interactions vary. CMS adjustment should follow measurement because improving one patch can worsen other luminance or saturation levels. See Color, Tint, and CMS controls.

Color space

A defined color representation. Depending on context, it can include primaries, white point, transfer functions, component encoding, and range. In a television menu, Color Space may instead be a manufacturer label for gamut selection or mapping behavior.

Color temperature

A description of whether white appears warmer or cooler. Television presets with names such as Cool, Standard, Warm, or Warm 2 are manufacturer controls, not standardized temperatures. A Kelvin value alone does not fully define a video white point. See color temperature and white balance.

Color volume

The colors that can be reproduced across luminance, not just at one brightness level. A display can cover a large two-dimensional gamut at one level yet lose saturation, luminance, or both at higher or lower levels.

Colorimeter

A tristimulus instrument with filtered detector channels intended to approximate standard color-matching functions. It can be fast and sensitive, but spectral mismatch can create display-dependent error. A suitable correction or profile can reduce selected errors but does not remove all uncertainty. See choosing a colorimeter. ^[8]

Contrast

The difference or ratio between dark and bright image regions. A television control named Contrast commonly changes white level or signal gain, not the panel’s native contrast ratio. Its effect can also differ between SDR and HDR.

D-G

Correlated color temperature (CCT)

A Kelvin value assigned to a chromaticity near the Planckian locus. CCT is useful as a secondary description, but different chromaticities can share a similar CCT. D65 is therefore not defined by “6500 K” alone. ^[9]

D65

The standard daylight illuminant used as the reference white chromaticity in the television systems discussed here. A display normally targets D65 chromaticity, not the complete spectral power distribution of daylight. D65 may look warm after prolonged viewing of a cooler picture. See why D65 can look yellow. ^[10]

Delta E (ΔE)

A family of numerical color-difference calculations, not one universal scale. A report should identify the formula, target, observer, measurement conditions, and whether the result includes luminance. Numbers from different formulas should not be treated as directly interchangeable. See reading a calibration report. ^[11]

Dithering

The intentional use of spatial or temporal variation to represent intermediate levels that are not directly available. Dithering can make gradients appear smoother, but it does not recreate information that was removed earlier in the chain.

Dolby Vision

A proprietary HDR system with multiple profiles and workflow options. Dolby documentation describes analysis, dynamic metadata, trims, and content mapping, but actual playback depends on the delivered profile, source, application, display, and selected mode. See HDR format differences. ^[12]

Dynamic metadata

Metadata that can vary over time, such as by scene, shot, or frame, to guide a compatible color-volume or tone-mapping process. Dynamic metadata is guidance, not a guarantee that every display will produce the same image.

Dynamic tone mapping (DTM)

A manufacturer or format-dependent process that analyzes the signal or picture over time and changes mapping decisions. It can preserve or emphasize different parts of the image, but the result may depart from a fixed reference-oriented mapping. See HDR tone mapping.

EOTF

Electro-optical transfer function, the relationship between a video signal at the display input and the light produced by a reference display. BT.1886 defines an SDR reference EOTF, while BT.2100 specifies PQ and HLG system behavior in different ways. ^{[2] [5]}

Filmmaker Mode

A picture-mode program with published requirements intended to disable specified post-processing and preserve frame rate, aspect ratio, color, and other presentation choices where supported. It is a useful starting point, not proof that every measured property is correct on every television. See choosing a picture mode. ^[13]

Full range / limited range

Two common digital signal-range conventions. The exact code values depend on bit depth and component format. A source-display mismatch can raise black, crush dark detail, clip highlights, or alter contrast. “Full” is not inherently higher quality than “limited.” See signal-range matching.

Gamma

A power-law description often used for SDR tone response and as a television menu label. Real SDR display targets can be pure power functions, BT.1886, or manufacturer approximations. Gamma affects tonal distribution, not just peak brightness. See how SDR gamma turns signal into light.

Gamut mapping

A process that converts colors from one gamut or color volume into another. Mapping may preserve hue, saturation, luminance, relationships between colors, or some compromise among them. There is no single universally correct result for every source and display.

Grayscale

A sequence of nominally neutral levels from black through gray to white. Grayscale calibration evaluates whether those levels remain near the target white chromaticity while following the intended luminance response.

H-N

HDR

High dynamic range television uses a system designed for a larger range of display luminance than conventional SDR. HDR is not one format. PQ and HLG are different HDR systems, and HDR10, HDR10+, and Dolby Vision add different delivery and metadata rules. See the HDR format guide. ^[5]

HDR Reference White

A production reference level used for diffuse white and graphics within an HDR signal, leaving headroom for brighter highlights. ITU-R BT.2408-9 gives reference relationships for PQ and HLG workflows. It is not the same as the display’s peak luminance. See HDR setup. ^[14]

HDR10

A commonly used HDR media profile built around PQ, at least 10-bit precision, BT.2020 signaling, and static metadata fields where present. A display still has to map the signal to its own luminance and color capabilities. Metadata can be absent, unknown, inaccurate, or ignored. ^[15]

HDR10+

A proprietary HDR system based on HDR10 compatibility plus SMPTE ST 2094-40 dynamic metadata. The metadata can vary by scene or frame, depending on the workflow, but the displayed result still depends on implementation and the display. ^[16]

HGiG

An industry best-practice framework for coordinating HDR behavior among displays, consoles, and games. A television mode labeled HGiG often aims to reduce extra mapping, but HGiG is not one universal pass-through switch and does not guarantee identical game behavior. See HDR gaming setup. ^[17]

HLG

Hybrid Log-Gamma, one of the two HDR television systems in BT.2100. HLG uses a scene-referred opto-electronic transfer function and a display-side system gamma that depends on nominal peak luminance and the viewing environment. It does not use the same absolute-luminance model as PQ. See PQ versus HLG. ^[5]

HDMI range

The source and display expectation for digital component range over an HDMI path. Menu names include Limited, Full, Low, Normal, Black Level, and RGB Range, but manufacturers do not use those labels consistently. Match the actual source output and display interpretation.

Luminance

Luminous intensity per unit projected area in a specified direction, commonly measured from a display in candelas per square metre. Luminance is not the same as a signal percentage, code value, picture-level label, or subjective brightness. See nits and absolute luminance. ^[7]

Mastering-display metadata

Static metadata describing the mastering display’s primary chromaticities, white point, and configured minimum and maximum luminance. SMPTE ST 2086 does not describe the brightest pixel in the content and does not prescribe a consumer television’s tone mapping. ^[18]

MaxCLL

Maximum Content Light Level metadata, intended to describe the maximum light level of an individual pixel in the encoded program. A value can be unknown or inaccurate, and a television is not required to use it in one specific way. ^[15]

MaxFALL

Maximum Frame-Average Light Level metadata, intended to describe the highest average light level of any frame in the encoded program. It is not the mastering display peak and does not describe every frame. ^[15]

Metadata

Information carried with or about the video signal. HDR metadata can describe mastering conditions, content light levels, or dynamic mapping guidance. Metadata does not replace the picture samples and does not guarantee one display result.

Near black

The region immediately above reference black. Near-black evaluation considers whether small signal differences remain visible and neutral without raised blacks, crushing, flashing, posterization, or unstable processing. See calibration verification.

Nit

A non-SI name commonly used for one candela per square metre (1 cd/m²). It describes luminance, not total light output, HDR quality, or the brightness of every part of a picture.

O-R

OETF

Opto-electronic transfer function, the relationship used at capture or production to convert scene light into a video signal. It is not the same as the display EOTF. HLG system behavior is often discussed using both an OETF and display-side system gamma. ^[5]

OLED

A self-emissive display technology in which pixels generate light individually. OLED can render black by driving pixels near or to zero, but actual near-black behavior, peak luminance, color volume, uniformity, aging controls, and processing vary by panel and television.

Overscan

Image enlargement that crops picture edges. Digital sources generally should be shown without unnecessary overscan when accurate framing and pixel mapping are required, but the correct control name varies. See test patterns and framing.

Pattern generator

A device, application, disc, internal display function, or software path that produces known test signals. A generator must be validated for resolution, range, color encoding, bit depth, transfer function, metadata, timing, and any conversions in the path.

Peak luminance

The highest luminance a display produces under specified conditions. A useful figure must state the signal format, picture mode, pattern size, duration, measurement method, display state, and whether the result is brief or sustained. See white level and peak brightness.

PLUGE

Picture Line-Up Generation Equipment. A PLUGE pattern contains reference black and nearby levels used to check or align the black threshold. The pattern and procedure must match the signal format. ITU-R BT.814-4 specifies conventional television PLUGE signals; HDR evaluation requires format-appropriate test signals and code values. See PLUGE and test patterns. ^[19]

PQ

Perceptual Quantizer, the reference EOTF standardized in SMPTE ST 2084 and used by the PQ HDR system in BT.2100. PQ maps signal values to an absolute luminance scale up to 10,000 cd/m². A display that cannot reproduce the encoded luminance range must map or clip values beyond its capability. See PQ and HLG. ^[1]

Primary colors

The independent color channels used to define an additive RGB system. Their chromaticities form a triangle on a chromaticity diagram. The triangle shows a two-dimensional boundary, not the brightness or full color volume available inside it.

Profiling / meter matching

A procedure that compares a colorimeter with a spectral reference instrument on the same display and derives a correction for that meter-display combination. Geometry, repeatability, display state, reference-instrument quality, and software method all affect the result. ^[8]

Reference monitor

A professional display designed for defined production or evaluation work. A consumer television can approach selected reference targets in a suitable mode, but similar chart results do not make it equivalent in stability, uniformity, interfaces, signal handling, controls, or operating requirements. See consumer TVs and reference monitors.

Reference white

A defined white level used as a production or viewing reference within a system. SDR reference white is commonly tied to the selected display luminance target. HDR Reference White is a diffuse-white production level below the available highlight range.

RGB balance

A chart or measurement showing the relative red, green, and blue contributions to nominally neutral grayscale levels. Equal plotted percentages do not mean equal spectral power. The chart must be read with its normalization method, luminance, target, and error metric.

Roll-off

A gradual compression of signal differences as output approaches a display limit. Roll-off can preserve some highlight or color separation that hard clipping would remove, but it changes the relationship between the source signal and displayed light. See tone-mapping behavior.

S-Z and numbers

SDR

Standard dynamic range television. In this guide, SDR usually refers to conventional television systems using BT.709 colorimetry and a relative display response such as BT.1886 or a selected gamma target. SDR is not defined by one universal peak luminance for every room. ^{[3] [2]}

Shadow detail

Distinguishable picture information near black. Preserving shadow detail does not mean raising the black floor until dark scenes look gray. The goal is to maintain intended separation above black within the display and room limits.

Sharpness

A television control that often adds or reduces edge enhancement rather than changing real source resolution. The neutral setting can be zero, a midpoint, or another value depending on the model and mode. See picture processing controls.

Signal range

The allocation of digital code values to black, white, and headroom or footroom. Range is part of the signal interpretation. A mismatch can alter black, white, contrast, and clipping even when every device reports the same resolution and HDR format.

Spectrophotometer / spectroradiometer

A spectral instrument that measures light in wavelength bands. In display calibration it can serve as a reference for profiling a faster colorimeter. Spectral resolution, sensitivity, stray light, calibration, geometry, and the display still limit the result.

Static metadata

Metadata that does not change scene by scene or frame by frame. HDR10 commonly carries static mastering-display and content-light metadata, where available. Static metadata is not the same as a fixed tone-mapping result. ^{[18] [15]}

System gamma

In HLG, a display-side relationship used to adapt the overall scene-to-display contrast for nominal peak luminance and viewing environment. It is not simply the same control or equation as an SDR gamma preset. ^[5]

Test pattern

A controlled signal designed to isolate a specific behavior, such as range, clipping, grayscale, chroma, sharpness, motion, or EOTF tracking. A pattern is useful only when its files, player, output path, and active display state are valid. See the test-pattern guide.

Tint / Hue

A basic television control that shifts color decoding, commonly along a green-to-magenta direction. On a correct digital path it may remain at its reset value, but that should be verified with a valid pattern or measurement rather than assumed from the label.

Tone mapping

The adaptation of luminance and often color from the source signal to the display’s usable capabilities. Tone mapping can include clipping, roll-off, scene analysis, metadata use, color-volume mapping, and preference-oriented changes. It is not automatically an error. See how tone mapping fits the signal to the screen. ^[20]

Transfer function

A defined mathematical relationship between scene light, video signal, and displayed light. OETF, EOTF, and opto-optical transfer function (OOTF) describe different parts of that chain. “Gamma” is often used loosely, so the exact function and direction should be identified.

Warm / Warm 2

Manufacturer preset names for a warmer white-balance starting point. They often move closer to D65 than cooler presets, but the label does not guarantee D65 or identical behavior across models, modes, inputs, or units. See why warm presets can look yellow.

White balance

The adjustment and verification of neutral grayscale chromaticity across luminance levels. Two-point and multipoint controls can interact with EOTF, clipping, color, and neighboring levels, so measured changes should be rechecked across the full mode. See white-balance calibration.

White clipping

Loss of distinction among bright signal values because one or more output channels have reached a limit. It can occur in SDR or HDR and may affect luminance, color, or both. A display can preserve luma steps while clipping an RGB channel.

White point

The chromaticity designated as neutral white for a color system or calibration target. For BT.709, BT.2020, and BT.2100 television work, the reference white chromaticity is D65. A white point is not defined by CCT alone. ^{[3] [4] [5]}

Wide color gamut (WCG)

A color gamut wider than a specified comparison gamut, often wider than BT.709 in consumer video discussion. WCG does not by itself mean HDR, high luminance, correct color mapping, or full BT.2020 coverage.

1D LUT

A one-dimensional lookup table that transforms each channel independently. It is commonly used for grayscale, tonal, or channel-response correction, but it cannot directly correct all cross-channel color interactions.

3D LUT

A three-dimensional lookup table that maps combinations of input color values to output values. It can correct complex color interactions within its measured and modeled limits, but accuracy depends on the signal path, patch set, interpolation, display stability, and verification.

4:2:0 / 4:2:2 / 4:4:4

Common component-sampling labels. 4:4:4 carries chroma samples at the full luma sampling grid, while 4:2:2 and 4:2:0 reduce chroma sampling in defined directions. These labels do not state bit depth, compression ratio, range, or whether the reconstruction is good. See 4:4:4, 4:2:2, and 4:2:0.