P3 is an
RGB color space
An RGB color space is any additive color space based on the RGB color model. An RGB color space is defined by chromaticity coordinates of the red, green, and blue additive primaries, the white point which is usually a standard illuminant, an ...
. DCI-P3 (Digital Cinema Initiative) is used with digital theatrical motion picture distribution
(DCDM). Display P3 is a variant developed by
Apple Inc.
Apple Inc. is an American multinational technology company headquartered in Cupertino, California, United States. Apple is the largest technology company by revenue (totaling in 2021) and, as of June 2022, is the world's biggest company ...
for wide-gamut displays.
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History
Development of the standard
In 2005,
Digital Cinema Initiatives, LCC in
Hollywood,
California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
released the ''Digital Cinema System Specification version 1.0'', which defined the
colorimetry
Colorimetry is "the science and technology used to quantify and describe physically the human color perception".
It is similar to spectrophotometry, but is distinguished by its interest in reducing spectra to the physical correlates of color ...
of what would become known as the DCI-P3 color space.
According to section 8.3.4 in the specification, the blue
primary color
A set (mathematics), set of primary colors or primary colours (see American and British English spelling differences#-our, -or, spelling differences) consists of colorants or colored lights that can be mixed in varying amounts to produce a gamu ...
is the same as
Rec. 709
Rec. 709, also known as Rec.709, BT.709, and ITU 709, is a standard developed by ITU-R for image encoding and signal characteristics of high-definition television.
The most recent version is BT.709-6 released in 2015. BT.709-6 defines the P ...
,
sRGB, and
Adobe RGB
The Adobe RGB (1998) color space or opRGB is a color space developed by Adobe Systems, Inc. in 1998. It was designed to encompass most of the colors achievable on CMYK color printers, but by using RGB primary colors on a device such as a compu ...
, with a dominant wavelength of 464.2
nm. The red primary is a slightly deeper red than sRGB and Adobe RGB, with a
dominant wavelength
In color science, the dominant wavelength is a method of characterizing a color's hue. Along with purity, it makes up one half of the Helmholtz coordinates. A color's dominant wavelength is the wavelength of monochromatic spectral light that evo ...
of 614.9
nm.
The most significant difference is the green primary which is much closer to the spectral locus than either sRGB or Adobe RGB. DCI-P3's green primary has a dominant wavelength of 544.2
nm. Adobe RGB's green primary is more blueish with a dominant wavelength of 534.7
nm. sRGB's green primary is more yellowish at 549.1
nm.
DCI-P3 covers 45.5% of the
CIE 1931 chromaticity diagram
The CIE 1931 color spaces are the first defined quantitative links between distributions of wavelengths in the electromagnetic visible spectrum, and physiologically perceived colors in human color vision. The mathematical relationships that defin ...
(see inset image), which describes the color
gamut
In color reproduction, including computer graphics and photography, the gamut, or color gamut , is a certain ''complete subset'' of colors. The most common usage refers to the subset of colors which can be accurately represented in a given circ ...
of daylight human vision (
Photopic vision
Photopic vision is the vision of the eye under well-lit conditions (luminance levels from 10 to 108 cd/m2). In humans and many other animals, photopic vision allows color perception, mediated by cone cells, and a significantly higher visua ...
) as determined experimentally in the 1920s. In that study, participants visually matched a mixture of red, green, and blue "primary" lights to specific, pure monochromatic colored lights. This defined the spectral locus, which is the outer rim of the diagram, and the maximum extent of human color vision.
A more practical gamut is that of ''reflected surface colors'' which is described by
Pointer's gamut. In this case, DCI-P3 covers 86.9% of Pointer's gamut.
Rec.709/sRGB only covers 69.4%.
While DCI-P3 was developed by the Digital Cinema Initiatives (DCI) organization, many of the relevant technical standards are published by the
Society of Motion Picture and Television Engineers
The Society of Motion Picture and Television Engineers (SMPTE) (, rarely ), founded in 1916 as the Society of Motion Picture Engineers or SMPE, is a global professional association of engineers, technologists, and executives working in the m ...
(SMPTE) such as SMPTE EG 432-1 and SMPTE RP 431-2.
On November 10, 2010, SMPTE published SMPTE EG 432-1:2010, which includes a variant of the color space using a
D65 white point
A white point (often referred to as reference white or target white in technical documents) is a set of tristimulus values or chromaticity coordinates that serve to define the color "white" in image capture, encoding, or reproduction. Depending on ...
(about 6503.51 K) instead of the ~6300 K white point of DCI-P3.
On April 6, 2011, SMPTE published SMPTE RP 431-2:2011 which defines the reference viewing environment.
Display technology
Initially, DCI-P3 was available with
theatrical
Theatre or theater is a collaborative form of performing art that uses live performers, usually actor, actors or actresses, to present the experience of a real or imagined event before a live audience in a specific place, often a stage. The p ...
xenon-arc projection systems. This emerging technology presented challenges for filmmakers working with digital media on desktop workstations—that is, how to accurately view the colorspace of the theatrical viewing environment during the production and post production process.
In 2008,
HP released the first "HP DreamColor" monitor which could display 97% of DCI-P3 color space.
In 2014,
Eizo
is a Japanese visual technology company, founded in March 1968, which manufactures display products and other solutions for markets such as business, healthcare, graphics, air traffic control, and maritime. The company is headquartered in Ha ...
introduced the first professional 4K monitor with support of the P3 color space.
In 2015, Apple's
iMac
iMac is a family of all-in-one Mac desktop computers designed and built by Apple Inc. It has been the primary part of Apple's consumer desktop offerings since its debut in August 1998, and has evolved through seven distinct forms.
In it ...
desktop became the first consumer computer with a built-in
wide-gamut display, supporting the P3 color space. Apple's implementation, known as Display P3, uses a D65 white point, and uses the sRGB
TRC (sometimes referred to as
gamma
Gamma (uppercase , lowercase ; ''gámma'') is the third letter of the Greek alphabet. In the system of Greek numerals it has a value of 3. In Ancient Greek, the letter gamma represented a voiced velar stop . In Modern Greek, this letter re ...
).
In 2016, the
UHD Alliance announced their specifications for
Ultra HD Premium which requires devices to display at least 90% of the DCI-P3 color space (in area, not volume).
Also in 2016, Apple,
Samsung
The Samsung Group (or simply Samsung) ( ko, 삼성 ) is a South Korean multinational manufacturing conglomerate headquartered in Samsung Town, Seoul, South Korea. It comprises numerous affiliated businesses, most of them united under the ...
, and
Microsoft
Microsoft Corporation is an American multinational technology corporation producing computer software, consumer electronics, personal computers, and related services headquartered at the Microsoft Redmond campus located in Redmond, Washing ...
released mobile and desktop devices with P3 support.
P3 colorimetry
DCI-P3 specifications are designed for viewing in a fully darkened theater environment. The projection system uses a simple 2.6 gamma curve, the nominal white luminance is 48 cd/m
2 with the white point defined as a
correlated color temperature
Color temperature is the color of light emitted by an idealized opaque, non-reflective body at a particular temperature measured in kelvins. The color temperature scale is used to categorize the color of light emitted by other light sources ...
of ~6300 K. It is incorrect to refer to this as "D63" as this white point is not a CIE standard illuminant, and is not on the
Planckian locus
In physics and color science, the Planckian locus or black body locus is the path or ''locus'' that the color of an incandescent black body would take in a particular chromaticity space as the blackbody temperature changes. It goes from deep ...
. Instead, the white point is slightly greener. This resulted from optimizing for best light output with the
xenon arc lamp
A xenon arc lamp is a highly specialized type of gas discharge lamp, an electric light that produces light by passing electricity through ionized xenon gas at high pressure. It produces a bright white light to simulate sunlight, with application ...
projectors commonly used in theaters.
Display P3 is a color space created by Apple Inc. It uses the DCI-P3 primaries, but instead of the ~6300 K white point, Display P3 uses the
CIE standard illuminant D65
CIE standard illuminant D65 (sometimes written D65) is a commonly used standard illuminant defined by the International Commission on Illumination (CIE). It is part of the D series of illuminants that try to portray standard illumination conditio ...
as the white point, which is the most common standard for self-illuminated displays and devices (sRGB and
Adobe RGB
The Adobe RGB (1998) color space or opRGB is a color space developed by Adobe Systems, Inc. in 1998. It was designed to encompass most of the colors achievable on CMYK color printers, but by using RGB primary colors on a device such as a compu ...
both use D65). Also, unlike the DCI-P3 projection gamma of 2.6, Display P3 uses the
sRGB transfer curve, which is approximately equivalent to a display with a 2.2 gamma. Display P3's gamut is approximately 50% larger than
sRGB in volume and 25% in surface.
Since
iPhone 7
The iPhone 7 and iPhone 7 Plus are smartphones that were designed, developed, and marketed by Apple Inc. They are the tenth generation of the iPhone. They were announced on September 7, 2016, at the Bill Graham Civic Auditorium in San Fr ...
, the built in camera creates images tagged with the Display P3
ICC profile
In color management, an ICC profile is a set of data that characterizes a color input or output device, or a color space, according to standards promulgated by the International Color Consortium (ICC). Profiles describe the color attributes of a ...
.
P3-D65 with the PQ TRC is also used for some of
Netflix
Netflix, Inc. is an American subscription video on-demand over-the-top streaming service and production company based in Los Gatos, California. Founded in 1997 by Reed Hastings and Marc Randolph in Scotts Valley, California, it offers a fil ...
deliverables, including
HDR and without
BT.2020
ITU-R Recommendation BT.2020, more commonly known by the abbreviations Rec. 2020 or BT.2020, defines various aspects of ultra-high-definition television (UHDTV) with standard dynamic range (SDR) and wide color gamut (WCG), including picture ...
container, but later Netflix added BT.2020 primaries too. Red of P3 is slightly outside BT.2020 triangle.
DCI-P3+ and Cinema Gamut
An expanded gamut known as the DCI-P3+ color space is also available, which in turn is a smaller version of the Cinema Gamut color space.
DCI-P3+ uses the same ~6300 K white point as DCI-P3. Cinema Gamut is specified as having a D65 white point.
References
[The Society of Motion Picture and Television Engineers, 2011, New York: ''RP 431-2, D-Cinema Quality – Reference Projector and Environment for the Display of DCDM in Review Rooms and Theaters'']
{{Color space
Color space
Film and video technology
SMPTE standards
Ultra-high-definition television