What Exactly is Adobe RGB?

A TV or projector that has the Adobe RGB color space is a key selling point for integrators to use to upgrade clients to 4K.

Adobe RGB is a standard that was first introduced in 1998 to coincide with Adobe’s launch of its Photoshop 5.0 program. Adobe says the color space adheres to International Color Consortium (ICC) guidelines.

According to Adobe, as part of an ICC-based color management system, color profiles are created for devices so colors in an image can be modified throughout the workflow process to compensate for any differences between devices.

Adobe includes its ICC profile, called the Adobe RGB color space, in all of its color managed software tools. Highlighting some of Adobe’s RGB specifications are these calibration points of interest (based on CIE Standards):

Reference White Point (CIE, 1931):

  • X=0.3127/Y=0.3290
  • Luminance level of white displayed should be 160.00 cd/m2

Chromaticity Coordinates (CIE, 1931):

  • Red: X=0.6400/Y=0.3300
  • Green: X=0.2100/Y=0.7100
  • Blue: X=0.1500/Y=0.0600

Outlining ITU-R BT.2020 Picture Characteristics

Back in August 2012, the International Telecommunications Union (ITU) Radio Communications Sector issued its recommendations for the reproduction of Ultra HD content. The initiative is called ITU-R Recommendation BT.2020 (also called Rec. 2020 or simply BT.2020) and it outlines broadcast for the delivery of audio and video, frequency management, and time signals and frequency standard omissions.

Arguably the most important components of the ITU’s recommendation from the installer perspective are the picture spatial and picture temporal characteristics, as well as the trade group’s recommendation for system colorimetry.

Here are some of the ITU-R’s recommendations from its BT.2020 technology outline:

Picture Spatial Characteristics:

  • Picture Aspect Ratio: 16:9
  • Pixel Count Horizontal x Vertical: 7,680 x 4,320/3,840 x 2,160
  • Pixel Aspect Ratio: 1:1 (Square Pixels)
  • Pixel Addressing: Pixel ordering in each row is from left to right, and rows are ordered from top to bottom

Picture Temporal Characteristics:

  • Frame Frequency in Hertz (Hz): 120, 60, 60/1.001, 50, 30, 30/1.001, 25, 24, 24/1.001
  • Scan Mode: Progressive
  • Chromaticity Coordinates (CIE, 1931)
  • Red Primary: X 0.708/Y 0.292
  • Green Primary: X 0.170/Y 0.797
  • Blue Primary: X 0.131/Y 0.046
  • Reference White (D65): X 0.3127/Y 0.329

To learn more about Adobe RGB and how the standard can help integrators upgrade clients to 4K, click here.