Adobe RGB color space
The Adobe RGB (1998) color space or opRGB is a color space developed by Adobe 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 computer display. The Adobe RGB (1998) color space encompasses roughly 30% of the visible colors specified by the CIELAB color space – improving upon the gamut of the sRGB color space, primarily in cyan-green hues. It was subsequently standardized by the IEC as IEC 61966-2-5:1999 with a name opRGB (optional RGB color space) and is used in HDMI.[1]
Abbreviation
opRGB
- Adobe RGB (1998) color space
- IEC 61966-2-5:2007
- ISO 12640-4:2011
Published
1997
1998
2007
November 7, 2007[1]
Historical background[edit]
Beginning in 1997, Adobe Systems was looking into creating ICC profiles that its consumers could use in conjunction with Photoshop's new color management features. Since not many applications at the time had any ICC color management, most operating systems did not ship with useful profiles.
Lead developer of Photoshop, Thomas Knoll decided to build an ICC profile around specifications he found in the documentation for the SMPTE 240M standard, the precursor to Rec. 709 (but not in primaries: 240M also defined EOTF and thus was display referred, sRGB was created by connecting BT.470 PAL and SMPTE C). SMPTE 240M's gamut is wider than that of the BT.709 gamut and the same as BT.470 NTSC (System B, G). However, with the release of Photoshop 5.0 nearing, Adobe made the decision to include the profile within the software.
Although users loved the wider range of reproducible colors, those familiar with the SMPTE 240M specifications contacted Adobe, informing the company that it had copied the values that described idealized primaries, not actual standard ones (in a special annex to the standard). The real values were much closer to sRGB's, which avid Photoshop consumers did not enjoy as a working environment. To make matters worse, an engineer had made an error when copying the red primary chromaticity coordinates, resulting in an even more inaccurate representation of the SMPTE standard. On the other hand red and blue primary are the same as in PAL and green is the same as in NTSC 1953 (blue is the same as in BT.709 and sRGB).
Adobe tried numerous tactics to correct the profile, such as correcting the red primary and changing the white point to match that of the CIE Standard Illuminant D50 (though that will also change the primaries and is thus pointless), yet all of the adjustments made CMYK conversion worse than before. In the end, Adobe decided to keep the "incorrect" profile, but changed the name to Adobe RGB (1998) in order to avoid a trademark search or infringement.[3]