Color gamut explained: Rec. 709 vs DCI-P3 vs Rec. 2020

A color gamut is the range of colors a camera can capture, a file format can store, or a monitor can physically display. In digital video, three color gamuts dominate: Rec. 709 for standard-definition and high-definition SDR video, DCI-P3 for digital cinema and Apple displays, and Rec. 2020 as the wide-color container for 4K HDR.

Understanding how these color spaces interact explains why a movie can look vibrant on a MacBook Pro screen but flat on an office monitor, and why 4K HDR movies are stored in a color space that no consumer television can fully display.

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Three color gamuts on the map of every visible color

• Rec. 709 / sRGBHD video, the web and most SDR
• DCI-P3 (Display P3)Mac screens; most HDR films are graded in it
• Rec. 2020The container of HDR and UHD video

What is a color gamut and how does the chromaticity diagram work?

To compare color spaces objectively, color scientists plot them on a two-dimensional chromaticity diagram. The most famous is the CIE 1931 color space chromaticity diagram, established by the International Commission on Illumination.

The curved, horseshoe-shaped outer perimeter of the diagram represents pure spectral colors—single wavelengths of light ranging from violet (around 380 nanometers) to deep red (around 700 nanometers). Everything enclosed within that boundary represents the complete range of colors visible to the average human eye.

Because electronic displays produce color by mixing Red, Green, and Blue subpixels, any screen’s color gamut can be plotted as a triangle inside that horseshoe:

1. The three corners: The three vertices of the triangle represent the physical Red, Green, and Blue primaries of that specific standard.
2. The enclosed area: The interior of the triangle represents every color shade that the display system can create by mixing those three primaries in varying proportions.
3. The white point: The center coordinates define reference white (such as D65, representing average noon daylight at 6504 Kelvin).

The larger the triangle, the wider the color gamut, meaning the system can reproduce more saturated greens, fiery reds, and deep oceanic teals that smaller triangles cannot reach.

The three gamuts at a glance (share of visible colors as commonly cited for the CIE 1931 diagram; figures vary with the method):

What is Rec. 709 and why was it the standard for so long?

Recommendation ITU-R BT.709, commonly abbreviated as Rec. 709, was introduced in 1990 to standardize high-definition television. Rec. 709 shares the exact same primary chromaticity coordinates as sRGB, the standard RGB color space created by HP and Microsoft in 1996 for computer monitors.

Rec. 709 covers about a third of the visible colors. It suited the CRT televisions and early LCDs it was designed for, but it leaves out many colors we see in nature:

• Emerald greens, saturated cyans, and rich foliage are compressed into yellowish greens.
• Saturated red roses and crimson sports cars clip into orange-red tones.
• Deep violet and indigo tones lose chromatic intensity.

Despite these limitations, Rec. 709 remained the universal broadcast standard for more than three decades because virtually every television, monitor, and smartphone manufactured between 1995 and 2015 could reliably reproduce it without complex color management. To learn how bit depth pairs with these gamuts, read 8-bit vs 10-bit color.

What is DCI-P3 and how does Apple Display P3 differ?

In 2005, the Digital Cinema Initiatives (DCI)—a joint consortium of major Hollywood studios including Disney, Warner Bros., and Sony Pictures—standardized DCI-P3 for theatrical digital cinema projectors.

DCI-P3 is a noticeably bigger triangle than Rec. 709, mostly toward green and red: neon, rich foliage and deep reds fit inside it.

In late 2015, Apple brought cinema-grade wide color to personal computing by introducing Display P3 with the 27-inch Retina 5K iMac. Today, Display P3 is standard across all MacBook Pro, MacBook Air, iPad Pro, and iPhone displays.

However, Display P3 is not identical to theatrical DCI-P3:

• Theatrical DCI-P3: Designed for dark cinema auditoriums. It uses a 2.6 gamma curve and a slightly greenish-yellow white point calibrated to xenon arc lamp projectors (correlated color temperature around 6300 K).
• Apple Display P3: Adapts the wide DCI-P3 primary color coordinates for desktop computing. It pairs those vibrant primaries with the standard sRGB 2.2 transfer curve and the D65 daylight white point (6504 K).

Because Display P3 uses the standard D65 white point, everyday desktop text and web graphics retain identical neutral white tones, while wide-color photography and video can expand into the richer DCI-P3 primaries.

What is Rec. 2020 and why do movies use it as a container?

Recommendation ITU-R BT.2020, published in 2012, defines the color space for Ultra-High-Definition Television (UHDTV). Its boundaries were chosen using monochromatic spectral laser primaries at 630 nm (red), 532 nm (green), and 467 nm (blue).

Rec. 2020 covers about three quarters of the visible colors, much more than Rec. 709, including most saturated colors found in nature.

Here is the central paradox of modern video: virtually no consumer display can show 100% of Rec. 2020.

Good consumer screens reach close to all of P3 and only part of Rec. 2020, and most HDR films are graded on monitors set to P3, with the result stored as Rec. 2020.

The film industry uses Rec. 2020 as an archival container. When a studio grades an Ultra HD Blu-ray or a 4K streaming master for Netflix or Apple TV+, the bitstream is flagged as Rec. 2020. However, the colorist works within the physical boundaries of DCI-P3. Using Rec. 2020 as a universal container ensures that as future RGB laser projectors and quantum-dot displays expand beyond P3, content will not have to be re-encoded from scratch. Explore dynamic range standards in What is HDR?.

What happens when a display cannot show a wide gamut color?

When an HDR video contains color coordinates that fall outside the physical capabilities of your screen, the playback engine must decide what to do with the out-of-bounds data. There are two primary approaches:

1. Gamut clipping: The display engine takes every color outside its triangle and snaps it directly to the nearest edge of its physical gamut. For example, if a scene features a glowing green laser sword encoded at the outer limits of Rec. 2020, an sRGB monitor clips all the saturated variations to maximum sRGB green (code value 0, 255, 0). The laser sword becomes a flat, solid neon blob with no internal highlight graduation, textural shading, or specular core.
2. Gamut mapping (compression): Instead of chopping off out-of-gamut shades, the rendering engine compresses the entire color space inward. Saturated extremes are mapped to the edge of the panel’s physical gamut, while colors just inside the boundary are scaled down proportionally. This preserves the delicate tonal steps, highlights, and shadow gradients inside saturated objects, though overall saturation is slightly lowered.

Methods for converting Rec. 2020 colors to a smaller gamut are described in Report ITU-R BT.2407; brightness gets the same kind of treatment, called tone mapping (see HDR formats compared).

How does macOS manage wide color gamuts across screens?

Apple Silicon Macs feature system-level color management through Apple ColorSync.

Unlike operating systems where wide-gamut monitors can cause regular desktop icons and skin tones to appear unnaturally oversaturated and neon-tinted, macOS uses system-wide ICC color matching:

• Source tagging: Every image, video stream, and window buffer carries a specific color space profile (such as sRGB, Display P3, or BT.2020).
• Display profiling: macOS reads the factory color calibration profile of the built-in Liquid Retina XDR screen or external monitor.
• Real-time conversion: Before presenting frames to the desktop compositor, macOS translates source color coordinates into the display’s native profile using floating-point math.

Open a Rec. 709 video on a Display P3 MacBook Pro and its colors stay inside the Rec. 709 triangle: skin tones look natural, not sunburned. Open a Rec. 2020 HDR film and the window can use the screen’s whole P3 range.

What to do next

Wide color gamuts make modern films look lifelike, but only when every step of the playback chain respects color space boundaries. Rec. 709 remains the standard for SDR video, Display P3 provides cinema-quality richness on Apple hardware, and Rec. 2020 acts as the master container for 4K HDR.

To see wide-gamut video as intended, use a player that respects each file’s color tags. MacLC does; it is free to download.