What is Rec.709? The HD colour standard, in plain numbers

Rec.709, formally ITU-R BT.709, is the international standard for HD video. It fixes the colours a screen can show (three primaries and a D65 white point), the brightness curve between signal and light (about gamma 2.4 on a display), the 16–235 legal range for 8-bit video, and the 1920×1080 frame. It shares its primaries with sRGB and covers roughly a third of visible colour, far less than Rec.2020. It remains the default delivery target because almost every phone, laptop, TV and streaming platform shows SDR video as Rec.709.

Most people meet Rec.709 as a menu option or a LUT name, and it is easy to use for years without knowing what it specifies. It is worth knowing, because it is the target almost every piece of video you finish is aimed at.

What is Rec.709, exactly?

Rec.709 is short for ITU-R Recommendation BT.709, published by the International Telecommunication Union in 1990 and revised several times since; the current edition is BT.709-6. It was written to standardise high-definition television, and it quietly became the standard for nearly all SDR video on every screen.

It defines four things that matter to anyone grading:

  • The gamut: which red, green and blue a screen uses, and therefore which colours exist.
  • The white point: D65, a daylight white around 6500 K.
  • The transfer curve: how signal values map to brightness.
  • The signal range and format: 1920×1080, and which code values mean black and white.

When footage "looks normal", it is almost always because it is Rec.709 being shown on a Rec.709 screen.

The numbers behind Rec.709

Source for the values below: ITU-R BT.709-6, the standard itself. Two rows are the exception. The display gamma comes from ITU-R BT.1886, and the gamut coverage is computed from the BT.709 primaries as a share of the CIE 1931 chart by area.

ParameterRec.709 value
StandardITU-R BT.709-6
Resolution1920×1080 (HD)
Red primary (x, y)0.640, 0.330
Green primary (x, y)0.300, 0.600
Blue primary (x, y)0.150, 0.060
White pointD65 (0.3127, 0.3290)
Gamut coverageAbout 36% of CIE 1931 visible colours
Camera curve (OETF)Power 0.45 with a linear toe
Display curve (EOTF)Gamma 2.4, via BT.1886
Luma weightsY = 0.2126 R + 0.7152 G + 0.0722 B
8-bit legal range16–235 luma, 16–240 chroma
10-bit legal range64–940 luma, 64–960 chroma
Bit depth8 or 10 bit

The luma weights are why green dominates perceived brightness, and why they differ from the older SD standard, Rec.601. Mixing the two up is a classic cause of slightly wrong skin tones after a conversion.

What gamma does Rec.709 use?

This is the most argued-over part of the standard, because Rec.709 itself only defines the *camera* side: a curve of roughly power 0.45 with a short linear segment near black. It never said how a display should show that signal.

That gap was closed in 2011 by BT.1886, which sets a display gamma of 2.4 for a dim grading room. So in practice "Rec.709" in a grading suite means Rec.709 primaries with a 2.4 display gamma.

Two consequences you will actually run into:

  • Gamma 2.2 vs 2.4. Bright offices and many consumer displays behave closer to 2.2, so a grade made at 2.4 can look slightly lifted and flatter on them.
  • The Mac gamma shift. macOS interprets the standard Rec.709 tag with a curve near 1.96, so an export looks washed out in QuickTime compared with Resolve's viewer. Resolve offers a *Rec.709-A* output tag for this. It is a viewing mismatch, not a broken file.

Legal range vs full range: what is the difference?

Video does not use every code value. In legal range (also called video or limited range), black sits at 16 and white at 235 in 8-bit, leaving headroom above and footroom below. Full range uses 0–255, which is what computer graphics and stills expect.

Neither is wrong. The problem is misinterpretation:

MistakeWhat you see
Legal file read as fullGrey blacks, dull whites, washed-out image
Full file read as legalCrushed shadows, clipped highlights, extra contrast

Deliver video in legal range unless a platform asks otherwise, and check that your editor and your player agree on the tag.

Rec.709 vs sRGB vs Rec.2020: how do they compare?

Source for the gamut row: each space's share of the CIE 1931 chart by area, computed from the primaries in ITU-R BT.709, IEC 61966-2-1 (sRGB), SMPTE RP 431-2 (DCI-P3) and ITU-R BT.2020.

Rec.709sRGBDCI-P3Rec.2020
Used forHD and SDR videoWeb, stills, UICinema, Apple displaysUHD and HDR video
PrimariesBT.709Same as Rec.709Wider red and greenMuch wider
Gamut (approx.)36%36%45%76%
White pointD65D65DCI white or D65D65
Display curveGamma 2.4 (BT.1886)About 2.2, piecewiseGamma 2.6 in cinemaPQ or HLG for HDR
Typical rangeLegalFullFullLegal

sRGB and Rec.709 share primaries and white point, so colours land in the same place; only the curve and usual range differ. That is why a photo and a video frame can match closely without any gamut conversion.

Rec.2020 is a much larger container. Its primaries sit near the edge of visible colour, and no consumer display reproduces all of it. HDR delivery pairs it with a PQ or HLG curve under BT.2100. Several log formats, Apple Log and N-Log among them, record into a Rec.2020 gamut, which is part of why they need a proper conversion down to Rec.709.

Why is Rec.709 still the delivery target?

Because it is what the audience's screens do. Phones, laptops, most TVs in SDR mode, YouTube, Instagram and every social feed show standard-range video as Rec.709. HDR is growing, but an SDR master is still required almost everywhere, and it is Rec.709.

That is why so much of post-production is getting footage *into* Rec.709. A standard picture profile records it directly. Log footage deliberately does not, and has to be converted. S-Log3 to Rec.709, D-Log to Rec.709 and Apple Log to Rec.709 cover that step for specific cameras. Choosing the right file for it is the job of the Rec.709 LUT post; this page is only the destination. When the same conversion has to land on every clip from a shoot, that is a batch job, which is where BatchTone comes in below.

Once there, the order is the usual one from colour grading basics: correct, then grade, then check skin tones, which show a wrong conversion before anything else does.

Getting a folder of footage into Rec.709

Understanding the standard does not make the conversion any less repetitive. A card of log clips from one camera needs the identical transform on every file, and that is the part that costs an evening.

A LUT is the portable way to carry that transform (what a LUT is covers the file), and BatchTone applies one to a whole folder of photos and video clips in one pass, with a per-file strength dial for clips exposed differently. The result is a folder already in Rec.709, ready to grade in Resolve, Premiere or Final Cut. There is a seven-day trial with everything unlocked.

If you have a handful of clips, you do not need it: the LUT slot in your editor does the same conversion one clip at a time. And it applies a transform, nothing more. It will not fix a clip that was badly exposed, and it does not replace the grade.

Common questions

Is Rec.709 the same as HD?

Rec.709 is the standard that defines HD video, including the 1920×1080 frame and its colour. In everyday use "Rec.709" refers to the colour part (gamut, white point and gamma), which is also used at other resolutions.

Is Rec.709 gamma 2.2 or 2.4?

The standard only defined the camera curve. BT.1886 later set 2.4 for display in a dim room, which is the grading norm; 2.2 is common on consumer screens in bright rooms.

Is Rec.709 good enough for YouTube?

Yes. YouTube's standard-range playback is Rec.709, and it is the correct target for any SDR upload. HDR uploads use Rec.2020 with PQ or HLG and get an automatic SDR version.

What is the difference between Rec.709 and Rec.2020?

Rec.2020 has a far larger gamut, about 76% of the CIE 1931 chart against 36% for Rec.709 (computed from the primaries in ITU-R BT.2020 and BT.709), and is used for UHD and HDR. Rec.709 is the smaller, universally supported SDR standard.

Does my camera record Rec.709?

If you use a standard, neutral or natural picture profile, yes. If you shoot a log profile, no: it records a flat image that needs converting to Rec.709 before delivery.

Read next

Explainers · 6 min read

Rec.709 LUT: which one your footage actually needs

A Rec.709 LUT converts log or flat footage into the colour space screens actually display, so it is a technical correction rather than a style. The right one is specific to your camera's profile — S-Log3, C-Log3, V-Log, N-Log and D-Log each need their own — and the manufacturer's own conversion LUT is almost always better than a generic pack. Apply it first, as the base, then grade on top of it; doing those in the other order is what makes a conversion look wrong.

Read it
Explainers · 4 min read

What is a LUT? The whole idea in five minutes

A LUT is a lookup table: a file that says, for a grid of input colours, what each one should come out as. Applying a LUT means looking up every pixel in that grid and interpolating between the nearest entries.

Read it
How-to · 4 min read

S-Log3 to Rec.709: converting a shoot, not a clip

S-Log3 records flat to keep highlight range, and a Rec.709 conversion LUT maps it back to normal contrast. The conversion itself takes a minute; the work is applying it to every clip on the card, which is a batch job rather than an edit.

Read it

One look. A whole shoot.

BatchTone applies your .cube LUTs across photos and video at once, with a strength dial on every file. Seven-day trial, everything unlocked.

Download for macOS