Real Surface Colours Research Articles

New RGB primary for various multimedia systems

Color gamut is one of the most important performance indicators of multimedia systems because a wide color gamut enables the reproduction of more real surface colors. The color gamut of multimedia systems depends on the RGB (red-green-blue) primary. There are various RGB primaries, such as ITU-R BT.709, ITU-R BT.2020, sRGB, Adobe RGB, and DCI-P3. ITU-R BT.709 and sRGB have a very small color gamut, while ITU-R BT.2020 has an extremely wide one. Adobe RGB and DCI-P3 have RGB primaries with the characteristics of color printers and digital cinema projectors, respectively. Also, some of these RGB primaries are not compatible with each other. Thus, the contents of a system should be converted for use in other systems. This paper proposes an RGB primary for use in various multimedia systems. In the proposed method, sRGB, Adobe RGB, and DCI-P3 – the most frequently used RGB primaries – are unified. In this paper, the color gamut efficiency and human visual preference of the proposed RGB primary are checked. The proposed RGB primary is expected to be utilized as an international-standard RGB primary for multimedia systems.

Comparison of real colour gamuts using a new reflectance database

AbstractA large set of data, comprising the spectral reflectances of real surface colours, has been accumulated. The data comprise 16 groups with different materials and include 85,879 measured spectra. From these data, CIELAB colorimetric coordinates were calculated under CIE illuminant D50 and the CIE 1931 standard colorimetric (2°) observer. Several published colour gamuts including those developed by Pointer and ISO reference colour gamut [ISO Graphic Technology Standard 12640‐3:2007] were compared using the present data set. It was found that the Pointer gamut is smaller than the new real data in most of the colour regions. The results also showed that the ISO reference colour gamut is larger than the new real accumulated data in most regions. The present finding indicates that there is a need to derive a new colour gamut based on the newly accumulated data for common applications. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 442–451, 2014

Super Hi-Vision Video Parameters for Next-Generation Television

The crux of the move to ultrahigh-definition television is to simply deliver a wider field of view, which only requires an increase in pixel count to 3840 × 2160 or 7680 × 4320 pixels, which are well accepted standards. However, this overlooks important factors such as color/tone rendition and motion portrayal, which could be crucial to delivering an enhanced visual experience with next-generation television (next-gen TV) systems. To this end, system parameters are proposed including colorimetry and frame frequency for next-gen TV. The proposed colorimetry system is based on the real RGB color system and has a color gamut covering 99.9% of real surface colors while using physically realizable RGB primaries. Further, a frame frequency of 120 Hz is proposed on the basis of subjective assessments of motion picture quality.

62.1: Five‐Primary‐Color 60‐Inch LCD with Novel Wide Color Gamut and Wide Viewing Angle

AbstractWe have newly developed a 5‐primary‐color 60‐inch FHD LCD with pixels composed of R1CGR2BY six sub pixels. The prototype is designed to reproduce all of real surface colors. We have also improved its viewing angle performances by applying a multi‐primary color matching technology.

Request for real surface colours

Color Research & ApplicationVolume 27, Issue 5 p. 374-374 Communications and Comments Request for real surface colours Michael R. Pointer, Michael R. Pointer mike.pointer@npl.co.uk National Physical Laboratory, Queens Road, Teddington TW11 0LW UKSearch for more papers by this author Michael R. Pointer, Michael R. Pointer mike.pointer@npl.co.uk National Physical Laboratory, Queens Road, Teddington TW11 0LW UKSearch for more papers by this author First published: 27 August 2002 https://doi.org/10.1002/col.10082Citations: 6AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article.Citing Literature Volume27, Issue5October 2002Pages 374-374 RelatedInformation

Gamut considerations for accurate colour reproduction on a computer display

This paper explores the influence of the gamut of cathode-ray tube (CRT) display devices on the reproduction of real surface colours. The commonly shown two-dimensional colour gamuts of additive devices are extended to a consideration of the relative luminance (and lightness) required of an image and its effects on the gamuts available in reproductions of commonly used test colours. The effect of flare on the available gamut is also explored at different levels of ambient illumination and screen reflectance. A surprisingly large number of, for instance, Macbeth ColorChecker Chart colours are shown to be outside the colour gamut of typical display devices, at the luminance needed for accurate colour reproduction. The number of colours considered is broadened to include a very extensive range of real surface colours which are compared with the display gamuts over the full range of luminance found in practice. Conclusions are drawn as to the best uses of colour spaces to describe colour gamuts and practical issues concerning gamut limitations in the accurate reproduction of surface colours.

Gamuts in Colour Reproduction

AbstractThe concept of the gamut of a colour reproduction system is explained, starting from the spectrophotometric description of colorants used. The extension is made from spectrophotometry to C1E 1931 XYZ colorimetry, a system still in use for the description of colour gamuts. Advantages of the CIE 1976 u’,v’ uniform chromaticity chart are discussed and related to CIE 1976 L*u*v* and L*a*b* uniform colour spaces. The use of Status A trilinear density plots is described and examined in terms of visual uniformity related to the Munsell system. The three-dimensional representation of a colour gamut in CIE 1976 L*a*b* colour space is related to colour sensitometric results which explain and allow Interpretation of the colorimetry. Applications of the systems reviewed are made to real surface colours and a variety of reflection and transmission photographic systems under different conditions of use, as well as to images formed by visual display units and broadcast television.

Considerations on new primaries for high definition television

A constant-luminance-coding (CIELAB) codec is presented for high-definition TV (HDTV) use that offers the possibility of enlarging the reproducible color TV spectrum by selecting a new set of primary colors. Tests on a BBC standard color card showed that this type of processing gives full flexibility for the choice of receiver and camera primaries and transparency for the transmission of all real surface colors. Subjective tests were carried out to investigate the importance of a wider color spectrum and the acceptability of CIELAB coding in a compatible HD-MAC system. It was found that more saturated primaries help to minimize calorimetric distortions if CIELAB coded signals are decoded by a conventional decoder.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A colour‐appearance transform for the CIE 1931 standard colorimetric observer

AbstractA physiologically plausible model of colour vision, based on the CIE 1931 standard colorimetric observer, is shown to provide a colour order system giving reasonably good predictions of the unique‐hue loci, of constant‐hue loci, and of constant‐saturation loci, as judged by comparison with the Munsell and NCS systems, for daylight illumination. When combined with a chromatic‐adaptation transform of the von Kries type, the model is also shown to give quite good predictions for real surface colours seen in tungstenlight (SA) illumination.

Color Gamut of Liquid Crystal Polysiloxanest

Abstract Polysiloxanes with suitable side-chains form a cholesteric liquid crystal phase that can be applied to a substrate to produce a durable coating which exhibits strong colours below the glass transition temperature. The peak reflectance is almost 0.5 and a nearly 1.0 peak reflectance can be obtained using a half-wave retardation plate coated on both sides with the material and viewed from one direction against a black background. Values below 0.5 and between 0.5 and 1.0 have been also obtained using suitable solvents and alignment techniques. Many desired spectral reflectance distributions can be then obtained because of the additive color properties of such cholesteric coatings. As a result it is possible to produce a larger colour gamut than with real surface colours such as pigments and dyes. Employing commercially available material experimental work was carried out demonstrating a greatly expanded colour gamut on the chro-maticity diagram. Also it is possible to modify the spectral reflectance distribution of coloured substrates by coating them with a material having a reflectance peak at the desired band of wavelength.

The Gamut of Real Surface Colours

AbstractA maximum gamut for real surface colours has been derived from the analysis of the colour coordinates of 4089 samples. The gamut has been derived in both the CIE 1976 L* u* v* colour space and the CIE 1976 L* a* b* colour space. The data are compared with the gamut produced by a typical dye set used in a photographic colour paper, and with the gamut of a typical television‐receiver display tube. Comparison with printing inks is difficult because of the large number available, but a large set of ink colours was used in deriving the maximum real‐colour gamut.

Publications Sponsored by the Colour Measurement Committee—VIII

Methods of describing the extent of agreement between the ΔE values calculated from a colour‐difference equation and the corresponding visual estimates of colour difference are discussed. Lack of agreement will be due to a combination of errors in the visual assessments, in the measurements, and in the colour‐difference equation itself. If there were no error in the instrumental measurements, the equation error for a particular colour difference would be the difference between the calculated ΔE value and the mean visual assessment of a very large number of observers (ΔVtrue). Experimental data in the form of acceptances (%) can be converted to ΔV values directly proportional to the observed colour differences. The overall equation error for n colour differences can be calculated from Eqn 1. The Davidson and Friede data are considered to be the most satisfactory of those presently available for testing the suitability of equations for industrial colour‐tolerance work and have been used to assess the accuracy of several well‐known equations. After allowing for errors in the visual assessment and in the instrumental measurements, σ(log ΔE) for the 1964 CIE equation was 0.22. Similar values (0.16‐0.23) were found for other equations. A lower a‐value was found for a very simple empirical equation essentially based on the x, y chromaticity diagram rather than on any transformation of it. The usual transformations tend to be based on data covering the whole chromaticity gamut, whereas real surface colours cover only a fraction of the possible area. This fact, together with the knowledge that most equations are based on data corresponding to small fields of view or large colour differences, could account for the relative failure of the standard equations.