This paper describes the specifications and usage of standard RGB color spaces promoted today by standard bodies and/or the imaging industry. As in the past, most of the new standard RGB color spaces were developed for specific imaging workflow and applications. They are used as interchange spaces to communicate color and/or as working spaces in imaging applications. Standard color spaces can facilitate color communication: if an image is in ‘knownRGB,’ the user, application, and/or device can unambiguously understand the color of the image, and further color manage from there if necessary. When applied correctly, a standard RGB space can minimize color space conversions in an imaging workflow, improve image reproducibility, and facilitate accountability. The digital image color workflow is examined with emphasis on when an RGB color space is appropriate, and when to apply color management by profile. An RGB space is “standard” because either it is defined in an official standards document (a de jure standard) or it is supported by commonly used tools (a de facto standard). Examples of standard RGB color spaces are ISO RGB, sRGB, ROMM RGB, Adobe RGB 98, Apple RGB, and video RGB spaces (NTSC, EBU, ITU-R BT.709). As there is no one RGB color space that is suitable for all imaging needs, factors to consider when choosing an RGB color space are discussed.