KNOWLEDGE MAP · REFERENCE
Keep the numbers. Keep their context.
Eight reference tables and a nominal-level calculator. Each value stays connected to its component, bit depth, transform direction and scope.
Keep the definition, the test and its limitations together.
Formula and interpretation +
D = round(876 × E′ + 64)
E′ = (D − 64) / 876Quantisation uses rounding to the nearest integer. This calculator covers nominal levels only, not the reserved-code rules or a complete codec. Full chroma uses a different centre/endpoint contract and is deliberately not offered.
Computed codes, not an HDR image or display measurement. 12-bit Video levels follow the corresponding BT.2100 scaling; 8-bit illustrates the BT.709 case.
01 / REFERENCE TABLES
A reference you can verify.
Read the row together with its units, direction and note. Tables scroll independently on small screens.
Shown: 8 / 8
RGB spaces and working systems
Basis, white and encoding are separate. A standard number is not a delivery specification.
| System | Primaries | White point | Encoding | Context |
|---|---|---|---|---|
| Rec.709 | Rec.709 | D65 | BT.709 OETF; display response is separate, including BT.1886 | HDTV / SDR, controlled path |
| sRGB | Same as Rec.709 | D65 | sRGB piecewise function | Graphics with a known profile |
| Display P3 | P3 | D65 | Same function as sRGB | Wide-gamut display graphics |
| DCI-P3 | P3 | x=0.3140, y=0.3510 | Power 2.6 for this variant | Display description; not the DCP file format |
| Rec.2020 | Rec.2020 | D65 | BT.2020 for SDR; BT.2100 specifies PQ/HLG | UHD; not automatically HDR |
| DaVinci Wide Gamut | DWG | D65 | Commonly DaVinci Intermediate, a separate function | Resolve working representation |
| ACEScg | AP1 | x=0.32168, y=0.33767 | Linear | Scene-referred CG / VFX |
| ACEScct | AP1 | x=0.32168, y=0.33767 | Log section + linear toe | Grading; requires separate output |
Transfer functions: direction and conditions
A simple power law and a specified reference EOTF are shown separately.
| Function | Input → output | Scale | Check |
|---|---|---|---|
| Gamma 2.4 | Normalised code → relative light in a simple model | L ∝ V²·⁴ | Not full BT.1886 with nonzero black |
| BT.1886 | Normalised signal → display luminance | Depends on Lb and Lw | Power 2.4 with black/white parameters |
| sRGB | Linear components ↔ codes | Relative | Piecewise, not exactly power 2.2 |
| Camera Log | Scene quantity ↔ code | Curve-dependent | Generation, gamut and precision from the specification |
| DaVinci Intermediate | Working linear values ↔ code | Relative | Not an ordinary display response |
| PQ / ST 2084 | Code → reference display luminance | Absolute; up to 10,000 cd/m² | Master and physical display peaks are separate |
| HLG | Scene → relative signal; display includes OOTF | Result depends on display system | OETF, system gamma, black and white |
Conditions. These functions do not replace primary conversion, codec processing or Video/Full interpretation.
SDR / HDR reference anchors
Every value has a context: white reference is not content peak.
| Property | SDR | PQ | HLG |
|---|---|---|---|
| Signal meaning | Known SDR path | Absolute reference EOTF | Relative OETF + OOTF |
| White | Agreed target and conditions; not a universal screen luminance | 203 cd/m² is a nominal HDR anchor under specified conditions | 75% ≈203 cd/m² on a 1000-cd/m² display, γ=1.2, reference black model |
| Peak | Depends on display target | 10,000 is the function maximum, not a required master peak | Display peak enters the rendering model |
| Primaries | Often Rec.709; another agreed gamut is possible | BT.2100 uses Rec.2020 | BT.2100 uses Rec.2020 |
Conditions. Physical luminance needs measurement. A browser picture or pixel code is not a nit measurement.
Y′CbCr: NCL coefficients
For the ordinary NCL model: Y′ = KrR′ + KgG′ + KbB′. Primes mark nonlinear components.
| Standard | Kr | Kg | Kb | Check |
|---|---|---|---|---|
| BT.601 | 0.2990 | 0.5870 | 0.1140 | Do not select from frame size alone |
| BT.709 | 0.2126 | 0.7152 | 0.0722 | Check metadata against the actual recording |
| BT.2020 NCL | 0.2627 | 0.6780 | 0.0593 | Do not confuse with BT.2020 CL or ICtCp |
Conditions. For neutral R′=G′=B′ the weights sum to the same Y′. A grey-ramp-only test may miss a matrix mismatch.
Bit depth and subsampling
Check value precision and spatial sampling density independently.
| Parameter | Meaning | Check and limitation |
|---|---|---|
| 8-bit | 256 integer bit patterns per component | Nominal range may not use every code |
| 10-bit | 1024 bit patterns | Not universally sufficient for every log curve |
| 12-bit | 4096 bit patterns | LogC4 requirement is not a rule for every camera; file size also depends on codec |
| 4:4:4 | Full relative chroma density | Does not guarantee no compression |
| 4:2:2 | Half horizontal chroma density | Sample position and filters matter |
| 4:2:0 | For ordinary progressive signals, half density on each axis | Does not mean Cr or Cb is absent |
Nominal digital levels
These are reference codes, not project presets or a complete list of interface-permitted values.
| Representation | Lower anchor | Upper anchor | Cb/Cr neutral | Note |
|---|---|---|---|---|
| 8-bit Y′ narrow | 16 | 235 | — | Black / white |
| 8-bit Cb/Cr narrow | 16 | 240 | 128 | −0.5 / +0.5; these are not black/white |
| 10-bit Y′ narrow | 64 | 940 | — | Black / white |
| 10-bit Cb/Cr narrow | 64 | 960 | 512 | Zero colour difference at centre |
| 12-bit Y′ narrow | 256 | 3760 | — | BT.2100 reference anchors |
| 12-bit Cb/Cr narrow | 256 | 3840 | 2048 | BT.2100 reference anchors |
| 8-bit Y′ full | 0 | 255 | — | Full integer-range model |
| 10-bit Y′ full | 0 | 1023 | — | Full: agree recipient support |
| 12-bit Y′ full | 0 | 4095 | — | Full: agree recipient support |
Checks along the signal path
Find the first mismatch; the same symptom can have several causes.
| Stage | Record | Compare |
|---|---|---|
| 1 · Source | Camera, curve, gamut, version | Actual recording versus assigned Input |
| 2 · Decode | RAW settings, matrix, levels | Same frame under known settings |
| 3 · Working | Tool-input representation | Operation order and LUT expectations |
| 4 · Rendering | Who prepares the image for display | Missing or duplicate output stage |
| 5 · File | Codes, pixel format, tags, range | Re-import with verified interpretation |
| 6 · View | App, OS, display, mode | Same file and frame in a controlled path |
Conditions. One screenshot or tag does not establish whole-pipeline correctness. Preserve the original during analysis.
CST, RCM and ACES: stage ownership
An architecture choice, not an image-quality ranking or a mandatory node recipe.
| Approach | Where it is defined | What to verify |
|---|---|---|
| CST | Explicit transforms at chosen locations | Inputs, outputs, order and additional mapping settings |
| RCM | Project and clip-level management | Input assignment, working system, automatic stages and Output |
| ACES | Specified system version and transform set | Input Transform, working encoding, Output Transform and interchange |
Conditions. Mixed workflows require deliberate stage ownership. Matching output names do not prove identical rendering.
TOPIC ILLUSTRATIONTHE ESSENTIAL IDEA
Cheat sheets and tables
A table shortens the search, not the list of required conditions. Establish the signal representation and intended output first; then choose the row that actually applies.
- Check Y′ and Cb/Cr ranges separately.
- Do not transfer conditions between standards because their names look similar.
- Use a number as a check, not a finished grade.
A reference is not a preset
A tabulated value requires the input, output and measured quantity. Gamma 2.4 does not describe all of BT.1886 at arbitrary black levels, and 203 cd/m² is not the required luminance of every white HDR object.
Use a row as a conditional assertion: under these conditions, expect this result. Establish missing conditions first. Delivery requirements take precedence over a value copied from a tutorial; standard and implementation versions matter too.
What this means in practice
For an SDR delivery, do not import 203 cd/m² from an HDR table merely because the row is labelled Reference White.
Assemble the whole signal description
A practical minimum includes primaries, white point, transfer function, component representation, range and bit depth. Subsampled Y′CbCr also needs chroma location and reconstruction assumptions. A codec name cannot replace these fields.
The space table is separate from workflow role. Primaries alone do not say whether an image is before or after rendering. Add the intended purpose: source, working interchange, finished master or viewing copy.
What this means in practice
Display P3 and DCI P3 are not interchangeable just because both contain P3: check white point, transfer function and the output contract.
A working basis is not a delivery format
DWG and ACES AP1 define useful computational bases, but their coordinates are not automatically ready for every monitor. Known encoding, target-display processing and correct output description are still required.
A wide intermediate representation can contain negative components or values above one. This does not justify clamping before every node. Target-gamut clipping and compression are separate operations with colour consequences.
What this means in practice
For DWG / Intermediate, record two fields: DWG for primaries/white; Intermediate for the nonlinear function. Do not label a delivery DWG instead of its actual output space.
HDR anchors belong to a model
PQ provides an absolute luminance relationship; its 10,000 cd/m² upper boundary is a function limit, not a required content peak or a claim about your screen. HLG depends on a display model: 75% corresponds to about 203 cd/m² under reference conditions, not on every display.
Keep nominal production white, mastering-display peak and content statistics separate. MaxCLL and MaxFALL describe different characteristics; a metadata field alone does not prove a correct content analysis.
What this means in practice
The 75% HLG row keeps its conditions: 1000 cd/m² and system gamma 1.2 for the reference calculation. When the display model changes, recompute instead of copying the value.
Identify the transform owner first
The workflow table does not rank RCM, ACES and explicit CSTs. It identifies ownership of input, working representation, rendering and output. Each technical operation needs a clear owner; extra nodes do not inherently add accuracy.
Test a short segment before applying a grade across the project. Record system version, input profile, expected LUT input and output. For multiple masters, ensure it is the output branch that changes while the working source remains available.
What this means in practice
If the project already performs input and output processing, inspect those settings first. Then decide whether a separate CST is needed and what local task it performs.
What a table cannot validate
Tables do not measure a display, identify an unknown file’s true profile or validate a decoder. The code calculator models one nominal component scale and rounding, not an actual codec.
Permitted and reserved codes follow rules beyond nominal levels. Full Cb/Cr cannot be inferred mechanically from Full Y′: chroma has a centre and endpoint details. Here Full is offered only for Y′/R′G′B′, while Cb/Cr uses nominal Video coding.
What this means in practice
For 10-bit Cb/Cr, zero gives 512 and nominal −0.5/+0.5 gives 64/960. Video Y′ instead uses 64/940. Verify the difference in the calculator.
DO. OBSERVE. EXPLAIN.
Verify a range using known codes
Use this page’s calculator: it checks a formula, not a real video export.
- 01
Check Video Y′
Choose 10-bit and check normalised 0 and 1, then try 0.5.
CHECKEndpoint codes are 64 and 940; any midpoint error is explained by rounding.
- 02
Change component
Switch to Video Cb/Cr and check −0.5, 0 and +0.5.
CHECKThe results are 64, 512 and 960; 940 was not used as the chroma limit.
- 03
Check Full separately
Select Full Y′/R′G′B′ and repeat 0 and 1. Do not conflate a component change with result interpretation.
CHECKThe 10-bit Full range is 0…1023, not 0…1024.
- 04
Check your delivery contract
Find your signal’s remaining fields in the tables and mark unknown ones.
CHECKThe code scale was not used as proof of HDR or a nit measurement.
Check your understanding
TEST THE EXPLANATION
A situation, not a trick question.
Answer first. Open the reasoning afterwards.
01Does 75% HLG always equal 203 cd/m²?+
No. This approximate correspondence requires the stated reference conditions. The display model and system gamma remain part of the calculation.
02Is BT.1886 simply x^2.4?+
The corresponding power form follows at zero black. The full reference EOTF depends on black and white luminance; the table separates those cases.
03Does 10-bit Cb/Cr end at 940?+
In nominal Video coding, 940 is the upper Y′ level. Cb/Cr uses 64…960 with neutral centre 512. This is not a list of all permitted or reserved codes.
Avoid these shortcuts
- Do not replace missing information with familiar settings.
- Keep the conditions with the number or definition.
From the model to your workflow.
Record the Resolve version, colour-management mode, input interpretation and viewing conditions. This reference helps define a check, but does not replace reviewing the full shot or validating a delivery file.
CHECK THE FOUNDATION
Sources and model limits.
Editorial review: 1 October 2026. Links identify the definitions and formulas; exercises are independent teaching examples.
- [4]ICC · sRGB ↗
Primaries, D65 and the piecewise transfer function.
- [5]ICC · Display P3 ↗
P3, D65 and the sRGB function.
- [6]ICC · DCI P3 ↗
White-point variants and power 2.6; not a DCP packaging specification.
- [7]ITU-R · BT.709-6 ↗
Sections 1, 3, 4: primaries, OETF, coefficients and 8/10-bit digital levels.
- [8]ITU-R · BT.1886 ↗
Annex 1: EOTF depending on black and white luminance.
- [9]ITU-R · BT.2100-3 ↗
PQ, HLG; Table 9: 10/12-bit integer representation.
- [10]ITU-R · BT.2408-9 (03/2026) ↗
HDR reference white and conditions for 75% HLG corresponding to about 203 cd/m².
- [11]ITU-T · H.273 (07/2024) ↗
Independent video-identification fields; metadata is not a transform.
- [12]ACES · White point ↗
x=0.32168, y=0.33767; D60-like is not exact CIE D60.
- [13]ACES · ACEScct ↗
AP1 and nonlinear scene encoding with a linear toe.
- [14]ACES · Output Transforms ↗
Target-display rendering and encoding; not merely a tag change.
- [15]Blackmagic · DWG / Intermediate v1.1 ↗
DWG and Intermediate specify distinct properties of a working representation.
- [16]Blackmagic · Color ↗
CST, RCM and Color tools. Menu details depend on the Resolve version.
- [18]ARRI · LogC4 specification ↗
Precision is format-specific: LogC4 specifies a 12-bit minimum; 10 bits is not universal.
- [19]FFmpeg · ffprobe ↗
Read stream fields without modifying the file; unknown does not prove a particular colour space.
- [20]FFmpeg · Content light metadata ↗
MaxCLL and MaxFALL are different content-metadata fields, not measurements of the current display.
- [21]OpenColorIO · Displays & Views ↗
Working data and viewing transforms are distinct.