A color space is the coordinate system a video's colors live in: a set of primaries (which pure red, green, and blue), a white point, and a transfer function (gamma - how numbers become brightness). The reason "the client's monitor looks different" is a definitional question, not a superstition: two devices can faithfully display the same file in two different spaces and produce two different pictures. The short version for video work: Rec.709 and sRGB share identical primaries and differ mainly in transfer function; deliver web and social video in Rec.709, and unconverted log footage will look flat everywhere until you do convert it.
The three ingredients
- Primaries - the exact chromaticities of the red, green, and blue the space is built on. Wider primaries = more of the visible spectrum addressable.
- White point - the chromaticity that counts as "white" (essentially all modern video uses D65).
- Transfer function - the curve mapping stored numbers to displayed brightness. This is the sneaky one, because two spaces can share primaries and white point yet still display differently.
The spaces that matter
| Space | Used for | The detail that matters |
|---|---|---|
| Rec.709 (ITU-R BT.709) | HD broadcast and web video delivery | Display reference ~BT.1886, roughly gamma 2.4 |
| sRGB (IEC 61966-2-1) | Web pages, graphics, stills | Identical primaries and white point to Rec.709; transfer ≈2.2 (piecewise) |
| Rec.2020 (ITU-R BT.2020) | UHD and HDR containers | Wide-gamut container; HDR transfer functions (PQ/HLR) ride inside it |
| DCI-P3 | Digital cinema projection | Wider than 709, narrower than 2020; the "cinema" gamut marketing references |
The 709/sRGB relationship is the one to internalize: same colors addressable, slightly different brightness curve. It is why a video exported "for web" generally looks right on computers regardless of the 709-vs-sRGB label, and why the tiny transfer difference rarely matters until someone color-critical is judging a frame against a reference.
Why the same video looks different on two screens
- Transfer mismatch - the file's curve and the display's assumption differ (the 709 ~2.4 vs sRGB ~2.2 family of mismatches).
- Untagged or misinterpreted files - players that ignore color metadata guess, and guesses vary by device and browser.
- Display variance - panels differ in gamut coverage and factory calibration; the same Rec.709 file on an accurate panel vs a saturated "vivid mode" panel is visibly two pictures.
- Camera log mistaken for a display space - S-Log, V-Log, D-Log and friends are acquisition spaces that look gray and flat by design; until converted to 709 they are not "wrong," they are unfinished. The drone version of this exact confusion is in the drone review guide.
What this means in review links
Web review players are SDR-first and mostly display your file as-is on whatever the viewer's screen assumes - which is fine news for Rec.709 deliverables: they preview faithfully on ordinary computers. The failure cases are the two extremes: unconverted log (flat, gray, "the client thinks the grade is missing") and HDR (tone-mapped or clipped unpredictably on SDR displays; HDR previews in browsers remain inconsistent). Both failure modes, plus the other drift sources, are diagnosed in why video looks different in a review link - and the approval-side discipline for color work (review the cut's decisions, do final QC on a calibrated display) is in the color-grading approval workflow. Practical delivery answer for web and social: Rec.709, converted, tagged.
FAQ
Is sRGB the same as Rec.709?
Almost - and the difference is the interesting part: identical RGB primaries and white point, but different transfer functions (~2.2 piecewise for sRGB vs the ~2.4 BT.1886 display reference for 709). For everyday video delivery the practical difference is small; for reference-grade viewing it exists.
What color space should I deliver for web and social?
Rec.709, converted from your working space and tagged. Every major platform's pipeline assumes it, and review players display it faithfully on ordinary screens.
Why does my log footage look gray and washed out?
Log is a camera acquisition space that flattens contrast to preserve highlight and shadow detail for grading - flatness is the design, not damage. It looks "wrong" until you apply the conversion (LUT or transform) into a display space like Rec.709.
What is Rec.2020 for?
It is the wide-gamut container for UHD and HDR - the space HDR signals reference. Delivering plain SDR web video in 2020 gains nothing, because virtually every player and screen in that chain is displaying 709/sRGB.
Do review tools color-manage playback?
Most web review players display the file as-is and rely on you having delivered display-ready video - which is exactly why converted, tagged Rec.709 is the review-upload standard. Delivering log or untagged files shifts interpretation onto each viewer's device, and you get different colors per reviewer.