In this article, Refik Telhan, a member of PRINTING United Alliance's Print Properties Committee (PPC), examines the growing challenge of observer metameric mismatch in soft proofing, particularly as wide color gamut (WCG) displays become more prevalent in the graphic arts industry. While early soft proofing systems using standard gamut (sRGB) displays showed strong visual consistency across observers, Telhan explains that modern WCG displays introduce new complexity due to the spectral characteristics of their narrowband primaries.
Historically, differences between printed output and display appearance were largely attributed to illuminant metamerism, especially related to fluorescent lighting and optical brightening agents in paper. However, Telhan argues that today’s primary issue is increasingly observer metamerism—where different individuals perceive the same displayed color differently, even under controlled viewing conditions. This occurs because WCG displays do not reproduce colors spectrally like real-world objects or printed materials, but rather create metameric matches using RGB primaries that vary significantly in spectral power distribution.
The article highlights that while printing inks and proofs are spectrally similar and thus visually consistent across observers, displays often are not scrutinized spectrally, even though they effectively function as light sources. As display primaries become narrower and more widely separated in wavelength to achieve wider gamuts, observer variability increases to unacceptable levels for color-critical work such as soft proofing.
Telhan further discusses the limitations of relying solely on the CIE 1931 standard observer and traditional colorimetric calibration, noting that a colorimetric match does not guarantee a visual match for all observers. He introduces the Observer Metameric Mismatch Index (OMMI), standardized in IEC TS 61966-13:2023, as a more appropriate metric for evaluating displays intended for multi-observer, color-critical environments.
Importantly, the article emphasizes that WCG displays are not inherently problematic, but their use must be informed by their observer variability. For personal creative work, a WCG display tuned to an individual observer may be appropriate. However, for soft proofing and collaborative workflows, Telhan argues that low OMMI displays and broadband primaries remain better suited.
He concludes by calling for display manufacturers and standards bodies—particularly ISO soft proofing standards—to incorporate OMMI into specifications, enabling users to make informed decisions when selecting displays for color-critical applications.
Become a member of the Print Properties Committee to shape the industry with the latest standards, tools, and innovation to drive print, packaging, and graphic communications. Access specifications developed by the Print Properties Commitee at www.gracol.org