CIE chart 1931. Adobe RGB vs. NTSC 1953 vs. DCI-P3

history

The International Commission on Illumination, also known as CIE, is a cooperative Global and exchange of information on all issues related to the science and art of light and lighting — color — vision — measurement of light and radiation Specially with regard to ICE photobiology and image technology is an independent, non-profit organization with a foundation Technical, scientific and cultural strong in 1991 as the International Photometric Commission CIP It serves member countries on a voluntary basis since its reorganization as the CIE in 1913. Light and brightness are known

Objectives of the CIE

1 Creating an international center to study all issues related to science and technology and the art of light and lighting and exchange information in this Context between countries

2 Compilation of standards and basic methods of metrology in the fields of light and lighting

3 Providing guidelines for the use of principles and methods of compiling international and national standards in the field of light and lighting

4Preparation and publication of standards, reports and other texts related to all issues related to science, technology and art in the field of light and lighting is

5 Maintaining communication and technical cooperation with other international organizations related to science, technology, standardization and art in the field of light and lighting

CIE1991 chart

The first quantitatively defined relationship between Moke length distributions in the electromagnetic-visible spectrum and physiological colors in color vision. Humans are the mathematical relationships that define these color spaces, essential tools for color management during exposure With colored ink, bright screens and recording devices such as digital cameras, this system was designed in 1931 by the International Commission on Ieclairag, which is known in English as the Commission. Internationally recognized lighting.

In Figure 1 below, you can see all the colors that the human eye can see, like the rest of the RGB and CMYK models.

color space

A color space is a wide range of colors that can be represented in a photo, specifically a color space can be seen as a set of a wider color model, for example RGB is a digital color model that combines He used red, green and blue colors with different shades, and this color space is based on the CIE scale as follows.

1SRGB

2Adobe RGB

3Pro Photo RGB

4NTSC1953

5PCI-P3-REC

Adobe RGB

RGB4 is a color space developed by Adobe Systems.INC and introduced in 1998 and after SRGB emerged as its competitor, in addition, Adobe RGB also appears in form number two for use in combination. Adobe Photoshop is designed with a wide range of complex color features. In general, Adobe RGB can be a space More advanced color considered this is often used by those working in digital arts and with more complex color management needs have.

S RGB

Before diving into how S RGB works, it should be noted that S RGB stands for Red Stahdod RGB. green This is the result A 1996 collaboration between HP and Microsoft for use with the emerging World Wide Web as well as Designed with computer monitors and color printers, as the name suggests, this color space profile is in mind It was taken to the color space was intended to become with the standard color space especially when more people They bought personal computers for their homes and more people used the Internet, this process took time It didn’t take long and without use after its introduction, S RGB became the default profile. Even today, S RGB is the closest thing. To a color space to a standard color space is the extensive use of S RGB to provide a more standardized experience in terms of brightness The colors shown and perceived in the digital device has helped is the most common color space and for those who Those who do not work in digital art or have more advanced needs are ideal in addition to photos taken using S RGB settings are displayed in the same way on the web.

DCI-P3

is an RGB color space first defined in 2005 as part of the Digital Cinema Initiative and used for distribution Motion pictures and digital effects used in 2005 LCC Digital Cinema Initiatives Hollywood and California Specifications Digital Cinema System released a version that defined the colorimetry of what was known as the DCI-2005 color space. According to section 83.4 in the specifications of the main blue color, that is Adobe RGB. S is RGB with a dominant wavelength of 462 nanometers The primary red is slightly deeper than Adobe RGB and S RGB with a dominant wavelength of 462.9 nm. The most important primary difference is green, which It is very close to the spectral location of S RGB and Adobe RGB. Primary green DCI-P3 has a dominant wavelength of 544.2 nanometers. Adobe RGB primary green is bluer with a dominant wavelength of 534.7 nm S RGB primary green is more yellow at 549.1

The CIE color chart covers 455% of PCI-P3. In the figure above, see the color spectrum of human vision in daylight or photopic vision. The experimental form in the 1920s describes in this study the participants visually a mixture of red colors. green and blue The primary with specific and pure colored lights matching this spectral location which is the outer edge of the chart and the maximum amount of vision Color Defines Humans A more scientific step is the surface colors reflected by the pointer range In this case, DIC-P3 covers 86.9% of the pointer range, and only S RGB covers 709% and 69.4%. While DCI-P3 was developed by the Organization for Digital Cinema Initiatives (CDCI) many related technical standards Published by the Society of Film and Television (SMPTE) such as SMPTEEG432 and SMPTRP431–2

Pro Photo RGB

GB7 is made by Kodak and usually only on high quality cameras It is available that covers the entire visible spectrum and 100% It was registered by Michael Poynter in 1980. Indeed, a wide range of colors that The coverage is so wide that even the colors that are included with the eyes Humans are not visible. If you look at the diagram, you will see two areas outside the spectrum Visible there is this inappropriate capacity can be when working with colors invisible to us When working in a color space with such a wide range of depth, it is recommended to create a slow problem Work in 16-bit to avoid poster effects, this often happens in 8-bit modes Occurs because the gradient steps are larger

NTSC-1953

C-19538 The first American standard for analog television broadcasting by the National Committee for the NTSC Television System in 1951 It was developed until 1953. In 1961, it was named M-System. In 1953, the second NTSC standard was adopted, which allowed Color TV broadcast compatible with stock available with black and white receivers Analogue is PAL and SECAM, NTSC color is mainly associated with the M system, the only other TV sector system for The use of NTSC was J system.

The National Television System was established in 1940 by the United States Federal Communications Commission (FCC) to resolve disputes between Companies over the introduction of a nationwide analog television system in the United States were established in March 1941. He designed a technical standard for black and white television based on the 1936 recommendations of the Radio Manufacturers Association (RMA). There have been technical advances in sideband technology, which creates the opportunity to increase image resolution NTSC 1940 scan line as a compromise between the 1941 RCA scan line standard currently used by network television. NBCRCA is used and the desire of Philco and Pumoht to increase the number of scan lines between 525 and 1936 chose this. The frame rate standard recommends 605 frames per second, which includes two interlaced fields per frame, 80,004 lines per second. fields and 30 fields per second. Other standards in the final recommendation are 5:202 aspect ratio and FM frequency modulation for the signal. A sound that was completely new at the time. In January 1950, to standardize color television, the FCC revised the 1950 line color television standard in brief. October 405 approved, developed by CBC The CBS system was incompatible with existing black and white receivers from a color wheel. rotation was used, it reduced the number of skif lines from 525 to 5 and increased the field rate from 405 to 60, but the frame rate It was only effective at 144 frames per second.Legal action by rival RCA kept commercial use of the system off until June 1951.

And regular broadcasting lasted only a few months until the production of all color televisions was apparently banned by the Defense Mobilization Office in October Because of the Korean War, it canceled its system on March 24, 1951, and replaced it with the NTSC color standard in December 1951. The cooperation of several companies, including RCA and Philco, developed. In December 1953, the FCC unanimously approved what is now called the NTSC color television standard, later known as RS-1700. It was defined as confirming that the standard and color maintained full backward compatibility with existing black and white televisions. Information color to black and white image by introducing a color subset exactly 315/e88 MHz usually as 3.579545 MHz and About 9.3 MHz was added, and the frequency was chosen so that the horizontal line rate of the horizontal line of the Crofion signal was exactly between Horizontal line rate modulation components of the illumination signal with partial degradation of the illumination signal can be filtered as well as visibility in sets Existing that it is not filtered to minimize due to the limitations of frequency division circuits in standard color time It was announced

Rec.2020

ITU-RBT.2020 recommendation, better known as Rec.2020 or BT.2020, various aspects of HDTV High definition HDTV with SDR standard dynamic range and wide WCG color gamut including resolution frame rate with Metric scan. Bit depth Preliminary color. RGB color display. Iuma-Chromachroma. . Subsamplin95 and a transfer function Opto-Electronic The first version of Rec.2020 was published on the website of the International Telecommunication Union (ITU) on August 23, 2012 and from At that time, two other versions have been published. Rec.2020 is extended for high dynamic range HDR by Rec.2100, which uses the same primary color as Rec.2020. does.

Technical details Rec.2020

Resolution: Rec.2020 defines two standard image formats 4K 2160 3840 and 8K 4320 7680. These two aspect ratios They have 16:9 and use square pixels.

Frame rate: Rec.2020 specifies the following frame rate:

23.97.6P . 24P . 25P . 29.97P . 30P . 50P . 59.94P . 60P . 100P . 119.88P . 12P

Only progressive scan frame rates are allowed.

Digital representation: Rec. 2020 defines the bit depth of 10 bits per sample or 12 bits per sample.

10 bits per sample Rec.2020 uses video levels where the black level is defined as 64 and the peak The name is defined as 940. Codes 10020–10023 and 0–3 are used for video timing reference. Codes 9 Up to 63 provide video data below the black level, while codes 1 to 41 provide video data above the nominal peak. they give.

conclusion

1 Adobe RGB and DCI-P3 color spectrum are larger S RGB color spectrum and have many colors in common with Adobe RGB. But in DCI-P3, the first color spectrum expands to red and yellow.

2 It is mostly used for websites, but for professional photographers, ProPhoto is used for editing and has a larger workspace for printing, and ProPhoto is suitable for color printing.

3DCI-P3 color space is suitable and used for gaming monitors.

4NTSC color space is used for content production.

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