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Highlights • Adding overripe seeds at post-fermentative stages modulated the copigmentation equilibria. • Differential Tristimulus Colorimetry assessed the improving effects on the wine color. • Double addition of seeds led to higher-stable wine color, darker, more vivid and bluish-hues. Abstract With the purpose of modulating the copigmentation equilibria of red wines, an environmentally sustainable process was performed based on post-fermentative addition of overripe seeds (OS). Simple (SW) and double (DW) addition were performed to produce different enrichment of phenolics from seeds, hence different copigmentation/polymerization ratios. The determination of the phenolic composition showed different global increases in OS-macerates wines (catechin, epicatechin, gallic acid and procyanidins B1 and B2). The double post-maceration (DW) was more effective than the simple post-maceration addition to improve the phenolic structure of wines. The application of Differential Tristimulus Colorimetry could assess the effects of this practice on the color characteristics and stability of wines. Results highlighted that both simple and double assays underwent colorimetric improvements against the control wines (CW, no seeds addition). DW led to the highest chromatic stability, showing lower lightness, higher chroma values and bluish hues than CW. This color difference was visually detectable. [ABSTRACT FROM AUTHOR]

Abstract BaBi 2 Nb 2 O 9 :Li+/Tm3+/Er3+/Yb3+ phosphors were successfully synthesized by the high-temperature solid-state method and up-conversion white-light emission has been achieved by tuning of the Tm3+ and Li+ contents. X-ray diffraction and room temperature photoluminescence were used, respectively, to investigate the structural and optical properties of the luminescent systems. Decay dynamics of 4F 9/2 levels in BBN:Tm3+/Er3+/Yb3+ and BBN:Er3+/Yb3+ phosphors have been analyzed to study the energy-transfer mechanism between Er3+ and Tm3+ ions. The introduction of Li+ ions into the BBN:0.5%Tm3+0.05%Er3+8%Yb3+ has induced an adjustment of tristimulus values shifting the chromaticity color coordinates of the phosphor towards to the ideal white region (x = 0.31 and y = 0.34). Furthermore, the high color purity white-light coming from the BBN:2%Li+0.5%Tm3+0.05%Er3+8%Yb3+ composition was obtained under moderate power density establishing the BBN phase as a host matrix able to generate RGB with energy saving. [ABSTRACT FROM AUTHOR]

This study investigated categorical perception for unique hues in order to establish a relationship between color appearance, color discrimination, and low-level (second-stage) mechanisms. We tested whether pure red, yellow, green, and blue, (unique hues) coincide with troughs, and their transitions (binary hues) with peaks of sensitivity in DKL-space. Results partially confirmed this idea: JNDs demarcated perceptual categories at the binary hues around green, blue and less clearly around yellow, when colors were isoluminant with the background and when accounting for the overall variation of sensitivity by fitting an ellipse. The categorical JND pattern for those three categories was in line with the effect of the second-stage mechanisms. In contrast, the results for unique red, binary red-yellow, and the JNDs for dark colors clearly contradicted categorical perception. There was a JND maximum around the center of red and JNDs strongly decreased away from the center. Although this observation alone would also be in line with categorical perception; unique red was shifted away from the center towards yellow so that unique red was close to the minimum instead of the maximum JND, hence contradicting categorical perception. In addition, we also showed that observers do not adjust unique hues more consistently than binary hues, confirming a previous study. Taken together, our findings suggest that some of the unique hues could be inherent in the early stages of color processing. At the same time, they also raise questions about complex effects of lightness, chroma and instructions on the measurements of JNDs and unique hues. [ABSTRACT FROM AUTHOR]

Abstract: Physically based rendering systems often support spectral rendering to simulate light transport in the real world. Material representations in such simulations need to be defined as spectral distributions. Since commonly available material data are in tristimulus colours, we ideally would like to obtain spectral distributions from tristimulus colours as an input to spectral rendering systems. Reproduction of spectral distributions given tristimulus colours, however, has been considered an ill‐posed problem since single tristimulus colour corresponds to a set of different spectra due to metamerism. We show how to resolve this problem using a data‐driven approach based on measured spectra and propose a practical algorithm that can faithfully reproduce a corresponding spectrum only from the given tristimulus colour. The key observation in colour science is that a natural measured spectrum is usually well approximated by a weighted sum of a few basis functions. We show how to reformulate conversion of tristimulus colours to spectra via principal component analysis. To improve accuracy of conversion, we propose a greedy clustering algorithm which minimizes reconstruction error. Using pre‐computation, the runtime computation is just a single matrix multiplication with an input tristimulus colour. Numerical experiments show that our method well reproduces the reference measured spectra using only the tristimulus colours as input. [ABSTRACT FROM AUTHOR]

Recently, wide colour gamut displays which adopt highly saturated primaries of red, green, blue have been rapidly applied. These displays can evoke more vivid and more pleasing effects for images. However, images shown on these newly developing wide gamut devices cannot achieve preferred quality under the control of conventional signal standards that are developed based on smaller colour gamut. To achieve the preferred display effects on wide gamut devices in digital image reproduction, a whole procedure to optimise gamut settings of colour primaries were proposed, in which particular algorithms were designed to render images from signal standard such as sRGB via simulating various gamut settings on the given display. Thus, the optimum specifications of colour primaries can be determined by calculations of the proposed preference index. Furthermore, a psychophysical experiment along with a detailed discussion were carried out as a verification, in which the consistence between the preference index calculation and the visual data could certify the effectiveness of the proposed procedure and algorithms. This study may help display researchers and manufactories by supporting some recommendations to determine the primaries of wide gamut devices in applications. [ABSTRACT FROM AUTHOR]

A new measurement method for laser displays is proposed to solve the problems caused by the extremely narrow spectra of lasers. This method is called the discrete centroid wavelength method, and is capable of simultaneously measuring the centroid wavelength and radiometric quantity of blue, green, and red lasers. First, its superiority to the tristimulus-value direct-reading method was verified by numerical analysis. Subsequently, the high accuracy of our method was confirmed by performing actual measurements of a uniform-luminance screen generated by RGB lasers. [ABSTRACT FROM AUTHOR]

The acid-base properties of Allura Red AC and Ponceau 4R azo dyes were investigated by spectrophotometric, potentiometric and tristimulus colourimetry methods. Ionization constants of the functional groups were also found in aqueous solutions of the dyes. It was discovered that the wavelength of the maximum light absorption of Allura Red AC and Ponceau 4R solutions does not change significantly over a wide pH range. As a result, spectrophotometric methods yield little information for assessing the acid-base properties of the dyes. It was shown with a help of the tristimulus colourimetry method that it is possible to determine the ionization constants of the functional groups of the dyes even when there is significant overlap of the absorption bands of the acid-base forms. The basic spectrophotometric characteristics of the main forms of Allura Red AC and Ponceau 4R in water and organic solvents were calculated. The molar absorbance coefficients of azo forms were shown to increase as the dielectric permittivity of the solvent increases. It was determined that in aqueous solution the dyes exist in the azo form over a wide range of acidity – pH 2–12 for Allura Red AC ( λ max = 505 nm; ε λ = 3.1·10 4 dm 3 mol −1 cm −1 ) and 1–13 for Ponceau 4R ( λ max = 510 nm; ε λ = 1.7·10 −4 dm 3 mol −1 cm −1 ). The most probable protonation/deprotonation schemes were theoretically determined for Allura Red AC and Ponceau 4R using DFT calculations. [ABSTRACT FROM AUTHOR]

The use of spectral reflectance as fundamental color information finds application in diverse fields related to imaging. Many approaches use training sets to train the algorithm used for color classification. In this context, we note that the modification of training sets obviously impacts the accuracy of reflectance reconstruction based on classical reflectance reconstruction methods. Different modifying criteria are not always consistent with each other, since they have different emphases; spectral reflectance similarity focuses on the deviation of reconstructed reflectance, whereas colorimetric similarity emphasizes human perception. We present a method to improve the accuracy of the reconstructed spectral reflectance by adaptively combining colorimetric and spectral reflectance similarities. The different exponential factors of the weighting coefficients were investigated. The spectral reflectance reconstructed by the proposed method exhibits considerable improvements in terms of the root-mean-square error and goodness-of-fit coefficient of the spectral reflectance errors as well as color differences under different illuminants. Our method is applicable to diverse areas such as textiles, printing, art, and other industries [ABSTRACT FROM AUTHOR]

This article addresses some general practices for the computation of CIE tristimulus values (TSVs), including different methods used for the interpolation, extrapolation, and truncation of data in the visible wavelength range. In each case, a quantitative analysis is presented on the basis of a dataset with 2365 spectral reflectances covering a wide color gamut, assuming six CIE illuminants and the two CIE standard colorimetric observers. For interpolation, it is found that among five tested methods, the (cubic) spline method is the best one when the spectral reflectance factors are uniformly sampled over the visible wavelength range. For extrapolation, it is found that the second-order extrapolation method gives better results than the use of nearest available data points or linear extrapolation methods. With respect to truncation, considering five different usual truncated ranges, it is found that the range from 360 to 780 nm provides more accurate results than the range from 380 to 780 nm currently recommended by CIE for nonfluorescent samples, and the use of the truncated range from 400 to 700 nm in place of the CIE-recommended range of 360 to 830 nm leads to TSVs with considerably high color differences of up to 0.9 CIELAB units. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 10-18, 2017 [ABSTRACT FROM AUTHOR]

A new spectral reflectance estimation method based on CIE XYZ values under multi-illuminants was proposed to obtain multi-spectral images accurately by using digital still cameras. CIE XYZ values under multi-illuminants were initially predicted from raw RGB responses by using a polynomial model with local training samples. Then, spectral reflectance was constructed from the predicted CIE XYZ values via the pseudo-inverse method. Experimental results indicated that the new spectral reflectance estimation method significantly outperformed the traditional colorimetric characterization method without requiring extra training samples or greatly increasing computational complexities. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 68-77, 2017 [ABSTRACT FROM AUTHOR]

A modified enzyme method is reported for the determination of cholinesterase inhibitors based on the use of a granulated composite carrier with immobilized butyrylcholinesterase. The detection system includes butyrylthiocholine as the substrate andN-(2,3-dimethyl-5-oxo-1-phenyl-3-pyrazoline-4-yl)-2-chloro-5-sulpho-4-iminobenzoquinone as a redox indicator. This method was characterized using carbamate physostigmine and sarin (O-isopropyl methylphosphonofluoridate). The method was also used in a simple tube detector. Evaluation was based on the observation with the naked eye of the decolorization of the redox indicator in comparison to a control time and by tristimulus colorimetry. The limits of detection were 0.5 µg/mL for physostigmine and 7 × 10−4 mg/m3for sarin visually, or 0.06 µg/mL for physostigmine and 1.1 × 10−4 mg/m3for sarin by colorimetry. [ABSTRACT FROM AUTHOR]

Color measurement by the colorized vision system is a superior method to achieve the evaluation of color objectively and continuously. However, the accuracy of color measurement is influenced by the spectral responses of digital sensor and the spectral mismatch of illumination. In this paper, two-color vision system illuminated by digital sensor and LED array, respectively, is presented. The Polynomial-Based Regression method is applied to solve the problem of color calibration in the sRGB and CIE  L⁎a⁎b⁎ color spaces. By mapping the tristimulus values from RGB to sRGB color space, color difference between the estimated values and the reference values is less than 3ΔE. Additionally, the mapping matrix ΦRGB→sRGB has proved a better performance in reducing the color difference, and it is introduced subsequently into the colorized vision system proposed for a better color measurement. Necessarily, the printed matter of clothes and the colored ceramic tile are chosen as the application experiment samples of our colorized vision system. As shown in the experimental data, the average color difference of images is less than 6ΔE. It indicates that a better performance of color measurement is obtained via the colorized vision system proposed. [ABSTRACT FROM AUTHOR]

Background: Bruising is one of the most common types of injury clinicians observe among victims of violence and other trauma patients. However, research has shown commonly used qualitative description of cutaneous bruise colour via the naked eye is subjective and unreliable. No published work has formally evaluated the reliability of tristimulus colourimetry as an alternative for assessing bruise colour, despite its clinical and research applications in accurately assessing skin colour. The purpose of this study was to systematically evaluate the test-retest and inter-observer reliability of tristimulus colourimetry in the assessment of cutaneous bruise colour.Methods: Two researchers obtained repeated tristimulus colourimetry measures of cutaneous bruises with participants of diverse skin colour. Measures were obtained using the Minolta CR-400 Chomameter. Commission Internationale d'Eclairage (CIE) L*a*b* colour space was used. Data was analysed using intraclass correlation coefficients (ICC), Cronbach's alpha, and minimal detectable change (MDC) on all three L*a*b* values.Results: The colorimeter demonstrated excellent test-retest or intra-rater reliability (L* ICC=0.999; a* ICC=0.973; b* ICC=0.892) and inter-rater reliability (L* ICC=0.997; a* ICC=0.976; b* ICC=0.982).Conclusions: With consistent placement, the tristimulus colourimetry is reliable for the objective assessment and documentation of cutaneous bruise colour for purposes of clinical practice and research. Recommendations for use in practice/research are provided. [ABSTRACT FROM AUTHOR]

We consider the general case of a set of three sensors that show a response proportional to analyte concentration and apply tristimulus analysis to represent the set of responses as tristimulus coordinates in a two-dimensional representation. These coordinates are a signature of the analyte and can be used for analyte identification. We extend the tristimulus analysis for cases where the sensors may present either positive or negative sensitivities, a situation in which the usual tristimulus analysis has limitations. We propose a different approach, taking the coordinates where the tristimulus vector crosses the unitary radius spherical shell, taking the angular coordinates as signature of the analyte. We also consider the case of binary mixtures and derive the set of equations that can be used to determine the relative concentration of each one of the analytes in the binary mixture from the tristimulus coordinates of the mixture. [ABSTRACT FROM AUTHOR]

The least squares method for computing colorimetric weighting tables is presented and its connection with the optimum weights method is investigated. Each requires solving three linear systems of equations with the same coefficient matrix but three different right hand side vectors. It is shown that the two methods have nearly the same performance when the wavelength interval of the data is large. The two methods however, will perform differently when Δ λ is small. Comparisons are also made between the least squares method, the optimum weights method, the zero- and second-order weighting tables, and the ASTM weighting tables, both the original 1985 tables and the new 2013 Tables V and VI. The results show that the least squares method is the best for measurement intervals equal to or lower than 10 nm, and is competitive with the optimum weights method for 20 nm steps. The results presented in this article will contribute to the work of CIE Technical Committee TC1-71 Tristimulus Integration as it seeks to make recommendations for the calculation of tristimulus values. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 125-142, 2016 [ABSTRACT FROM AUTHOR]

Finding the spectral features of color sample sets is a main issue of colorimetry. It is widespread to apply Principal Component Analysis in these researches. Several studies were written about the reconstruction of samples with known spectra using principal components, and some works dealt with approximate reconstruction from tristimulus values. Our study examines how spectral reconstruction done with genetic optimization works in case of different illuminants. The authors have taken only the tristimulus values of the color samples given. Also, they examine the reconstruction in case of illuminants that have unknown spectral power distributions, then they give the solution for these cases in brief. [ABSTRACT FROM AUTHOR]

The phenolic composition (by HPLC-DAD-MS) and color characteristics (by Imaging Tristimulus Colorimetry) of four strawberry cultivars that have shown good climate adaptation to subtropical area (Nikte, Zamorana, Jacona and Pakal) have been assessed. 24 monomeric phenolics were identified, including 15 anthocyanins, 5 phenolic acids, 1 flavanol and 4 flavonols. Nikte and Zamorana showed the highest phenolic potential mainly due to their higher content of anthocyanins, while Pakal was richer in phenolic acids. Regarding color, Nikte and Zamorana were the more similar cultivars having the lowest values of lightness and hue. On the contrary, the color of Pakal was quite different from all the rest, due to the specific distribution between pelargonidin and cyanidin. The inclusion of both phenolic and colorimetric information in the Linear Discriminant Analysis allowed reaching very good discriminations among cultivars. [ABSTRACT FROM AUTHOR]

Color measurements, including physical appearance, are important yet often misunderstood and underappreciated aspects of a control strategy for drug substances and drug products. From a patient safety perspective, color can be an important control point for detecting contamination, impurities, and degradation products, with human visual acuity often more sensitive for colored impurities than instrumental techniques such as HPLC. Physical appearance tests and solution color tests can also serve an important role in ensuring that appropriate steps are taken such that clinical trials do not become unblinded when the active material is compared with another product or a placebo. Despite the importance of color tests, compendial visual tests are not harmonized across the major pharmacopoeias, which results in ambiguous specifications of little value, difficult communication of true sample color, and significant extra work required for global registration. Some pharmacopoeias have not yet recognized or adopted technical advances in the instrumental measurement of color and appearance, whereas others begin to acknowledge the advantage of instrumental colorimetry, yet leave implementation of the technology ambiguous. This commentary will highlight the above-mentioned inconsistencies, provide an avenue toward harmonization and modernization, and outline a scientifically sound approach for implementing quantitative technologies for improved measurement, communication, and control of color and appearance for both solutions and solids. Importantly, this manuscript, for the first time, outlines a color method validation approach that is consistent with the International Conference on Harmonization's guidance on the topic of method validation. © 2015 Wiley Periodicals, Inc. and the American Pharmacists Association J Pharm Sci 104:3299-3313, 2015 [ABSTRACT FROM AUTHOR]

An integrated spectral imaging system constructed by synchronizing a programmable light source, a high-speed monochrome camera, and a display device is proposed to produce tristimulus images of static and moving objects effectively in real time onto the display. This system is called the CIE-XYZ display. Active spectral illuminants, containing both the device characteristics of camera and display, are projected onto object surfaces as time sequence. The images are captured synchronously by the camera and quickly transmitted to the display device in the RGB signal form so that the accurate tristimulus images are displayed. First, we describe the principle of the CIE-XYZ tristimulus display. The theoretically optimal illuminants contain negative parts in the spectral curves. Second, we design practical illuminants with all positive spectral curves. The color images in our system are composed of the time sequence of RGB component images. Then, the synthesized color images on the display contain color artifacts when objects move fast. An image processing algorithm for correcting the motion color artifact is proposed based on optical flow estimation using a graphics processing unit. The comprehensive performance of the proposed system and algorithms is examined using both static and moving objects. © 2014 Wiley Periodicals, Inc. Col Res Appl, 40, 329-340, 2015 [ABSTRACT FROM AUTHOR]

Background The actual skin colorimeters analyse reflect values from a limited number of broad spectral bands and consequently present limited reproducibility and specificity when measuring skin colour. Here, Antera 3D®, a new device which uses reflectance mapping of seven different light wavelengths spanning the entire visible spectrum, has been compared with Mexameter® MX-18, an established narrow-band reflectance spectrophotometer and with Colorimeter® CL-400, an established tristimulus colorimetric instrument. Methods Thirty volunteers were exposed to a controlled ultra-violet B light. Measurements with Antera 3D®, Mexameter® MX-18 and Colorimeter® CL-400 were done before treatment and after 2, 7 and 14 days. Results Antera 3D® showed to have a better sensitivity and specificity than Mexameter® MX-18 regarding the melanin parameter. A similar sensitivity between Antera 3D® and Mexameter® MX-18 was found for erythema determination and also for the Commission Internationale de l'Eclairage L*, a* and b* parameters between Antera 3D® and Colorimeter® CL-400. Good correlations were observed for all the parameters analysed. Repeatability of Mexameter® MX-18 and Colorimeter® CL-400 values were lower than that of Antera 3D® for all the parameters analysed. Conclusion Antera 3D®, such as Mexameter® MX-18 and Colorimeter® CL-400, are robust, sensitive and precise equipment for the skin colour analysis. [ABSTRACT FROM AUTHOR]

Background The actual skin colorimeters analyse reflect values from a limited number of broad spectral bands and consequently present limited reproducibility and specificity when measuring skin colour. Here, Antera 3D®, a new device which uses reflectance mapping of seven different light wavelengths spanning the entire visible spectrum, has been compared with Mexameter® MX-18, an established narrow-band reflectance spectrophotometer and with Colorimeter® CL-400, an established tristimulus colorimetric instrument. Methods Thirty volunteers were exposed to a controlled ultra-violet B light. Measurements with Antera 3D®, Mexameter® MX-18 and Colorimeter® CL-400 were done before treatment and after 2, 7 and 14 days. Results Antera 3D® showed to have a better sensitivity and specificity than Mexameter® MX-18 regarding the melanin parameter. A similar sensitivity between Antera 3D® and Mexameter® MX-18 was found for erythema determination and also for the Commission Internationale de l'Eclairage L*, a* and b* parameters between Antera 3D® and Colorimeter® CL-400. Good correlations were observed for all the parameters analysed. Repeatability of Mexameter® MX-18 and Colorimeter® CL-400 values were lower than that of Antera 3D® for all the parameters analysed. Conclusion Antera 3D®, such as Mexameter® MX-18 and Colorimeter® CL-400, are robust, sensitive and precise equipment for the skin colour analysis. [ABSTRACT FROM AUTHOR]

In photorealistic image synthesis the radiative transfer equation is often not solved by simulating every wavelength of light, but instead by computing tristimulus transport, for instance using sRGB primaries as a basis. This choice is convenient, because input texture data is usually stored in RGB colour spaces. However, there are problems with this approach which are often overlooked or ignored. By comparing to spectral reference renderings, we show how rendering in tristimulus colour spaces introduces colour shifts in indirect light, violation of energy conservation, and unexpected behaviour in participating media. Furthermore, we introduce a fast method to compute spectra from almost any given XYZ input colour. It creates spectra that match the input colour precisely. Additionally, like in natural reflectance spectra, their energy is smoothly distributed over wide wavelength bands. This method is both useful to upsample RGB input data when spectral transport is used and as an intermediate step for corrected tristimulus-based transport. Finally, we show how energy conservation can be enforced in RGB by mapping colours to valid reflectances. [ABSTRACT FROM AUTHOR]

The tristimulus color sensor system, a trichromatic camera, is developed to estimate the spectral radiance of objects. However, since the spectral sensitivity of the system does not match the Commission International de l’Eclairage (CIE) 1931 color matching function, it yields inaccurate colorimetric and spectral information. This work proposes methods using two light sources for estimating accurate spectral radiance and verifies that the accuracy achieved using these two illuminant methods exceeds that achieved using single illuminant methods. The two illuminant methods successfully reduce the mean color difference in CIELAB from 31.24 to 0.8 and provide a spectral accuracy of 0.0103. Furthermore, a tristimulus color sensor system is developed to verify the performance of these methods. [ABSTRACT FROM AUTHOR]

Because quince is a fruit that shows a very strong tendency for developing an intense browning when exposed to air, even though for short periods of time, the aim of this work was to evaluate the kinetics of colour change for quince exposed to atmospheric air at ambient temperature over a period of 2 hours. The quince was cut into slices that were left exposed to air, and colour measurements were done right after cutting and every 5 min, using a tristimulus colorimeter measuring the CIELab coordinates, L*, a* and b*. The results confirmed that quince suffers a high degree of browning, with total colour difference increasing strongly from 0 to 30 and browning index increasing from 50 to near 140. Furthermore, the major colour changes occurred during the first 30 min of exposure. Different models were tested to fit experimental data and the results showed that the most commonly used models, zero-order and first-order kinetics were totally inadequate in the present case, while the less cited models revealed to be very good at describing the kinetics of colour change for quince: logistic, modified Maskan and exponential rise. [ABSTRACT FROM AUTHOR]

Tristimulus values are spectrum integrals, involving a test light, that predict the quantities of three primary lights that when mixed together will match the test light. As described widely elsewhere, tristimulus values depend on the selected primary lights. However, tristimulus values are invariant to change of the integrand's domain (e.g., from wavelength to frequency), and also to change of range (e.g., from quanta to energy units). Starting with that invariance, this tutorial note explains how to transform the factors in the tristimulus-value integrand so as to obtain consistency among these representations of the tristimulus value. [ABSTRACT FROM AUTHOR]

An introduction is presented in which the editor discusses various reports within the issue on topics including the metal-like packaging printing, recoloring method for textile fabric images, and tristimulus values.

The problem of choice of tristimulus color coordinates which uniquely depend on chromophore concentration in an investigated material has been considered. A theoretical study shows that there are no simple analytical formulas for such dependences, and the majority of tristimulus coordinates of various color spaces: RGB, CIE ( XYZ), CIE ( L*a*b*), CIE ( L*C*H*), HSB, and CMYK poorly correlate with the concentration of molecules responsible for color. However, analysis of published papers on this subject provides abundant evidence showing that at least one tristimulus coordinate of the CIE ( L*a*b*) color space, specifically L* (lightness), is related to chromophore concentration C by a simple, steadily descending exponential function. The empirical formula L* = L*( C) can be successfully applied for instrumental treatment of experimental colorimetric data for the determination of chromophore concentrations. [ABSTRACT FROM AUTHOR]

In this study, we propose color images with color enhancement for congenital red-green color deficiency on the basis of the model proposed by Mochizuki et al. [In Terrassa, Spain: Proceedings for CGIV, Springfield VA: IS&T 2008;208-213] with the aim of facilitating color customization in displays used by color-deficient observers. Three types of color enhancements for deficiency were addressed in this study: colors were enhanced along the protan confusion line (i.e., P-enhancement), deutan confusion line (i.e., D-enhancement), and a line between the protan and deutan confusion lines (i.e., mix-enhancement). We investigated the color-enhanced image that is most preferred by each group of protan, deutan, and normal observers. Protan and deutan in this study indicate observers that are both dichromats and anomalous trichromats. Nine protan, nine deutan, and six normal observers participated in the experiment. The results showed that among the three types of color enhancements, the D-enhancement provided the best performance for protan observers. For deutan observers, all three types provided effective enhancement, although the P- and mix-enhancements were slightly better than the D-enhancement. Our results indicated that color enhancement increases the preference evaluations of protan and deutan observers. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 234-251, 2014; Published Online 20 February 2013 in Wiley Online Library (). DOI 10.1002/col.21795 [ABSTRACT FROM AUTHOR]

Previous attempts to predict chromatic-adaptation correspondence have led to a sharpening dilemma-i.e., Von Kries primaries are chosen that do not include in the positive octant all the realizable (x,y) chromaticities. This leads to paradoxical adaptation predictions for the colors that have negative Von Kries coordinates. A solution is proposed here that expresses the asymmetric-matching relation of chromatic adaptation as the product of two matrix transformations, given source illuminant 1 and destination illuminant 2: from source tristimulus values via adaptation matrix 1 to the adapted state coordinates, and from the adapted state via the inverse of adaptation matrix 2 to the destination illuminant tristimulus values. To avoid the sharpening instability, the entire spectrum locus must lie within the positive octant of the adapted state tristimulus space. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 275-278, 2014; Published Online 14 March 2013 in Wiley Online Library (). DOI 10.1002/col.21799 [ABSTRACT FROM AUTHOR]

An innovative imaging colorimeter measurement system which corrects tristimulus images by referencing an integrated spot spectroradiometer is introduced. Improvements offered to the display test industry by the new measurement system over current colorimeter designs are verified by measurements with comparable instruments and the analysis of a modern mobile display. [ABSTRACT FROM AUTHOR]

Abstract: This work reports the study of the application of simple chemical sensors based on carbon nanostructure composite thin films for the detection of Fusarium sp., Drechslera sp., Aspergillus sp. section Nigri and Aspergillus sp. section Circumdati fungi present in melons (Cucumis melo Naudin). The responses of chemical sensor conductance G and capacitance C at 27kHz were measured and used to calculate their ΔG and ΔC variations for melons during the ripening process under shelve conditions with intentionally promoted proliferation of Fusarium sp., Drechslera sp., Aspergillus sp. section Nigri and Aspergillus sp. section Circumdati fungus. These fungi are known to be frequent agents of occurring rot of melon during storage. Its early detection allows a relevant increase in shelf life, and in situ monitoring of fungal infections represents a very efficient tool to improve storage quality. The sensors response showed that the presence of fungi in melons can be electronically identified during the ripening process. We applied a method analogous to that used in colorimetry, the construction of the tristimulus space, to calculate the coordinates that can be univocally represented in a bidimensional graph, characterizing the sample. We show that the coordinate sequence constitutes a path evolving from the uninfected fruit to the fungi-only coordinates in a 20 days sequence of measurements after fungi inoculation. [Copyright &y& Elsevier]

Abstract: Color perception plays a major role in the consumer evaluation of perfume quality. Consumers need first to be entirely satisfied with the sensory properties of products, before other quality dimensions become relevant. The evaluation of complex mixtures color presents a challenge even for modern analytical techniques. A variety of instruments are available for color measurement. They can be classified as tristimulus colorimeters and spectrophotometers. Obsolescence of the electronics of old tristimulus colorimeter arises from the difficulty in finding repair parts and leads to its replacement by more modern instruments. High quality levels in color measurement, i.e., accuracy and reliability in color control are the major advantages of the new generation of color instrumentation, the integrating sphere spectrophotometer. Two models of spectrophotometer were tested in transmittance mode, employing the d/0° geometry. The CIEL ⁎ a ⁎ b ⁎ color space parameters were measured with each instrument for 380 samples of raw materials and bases used in the perfume compositions. The results were graphically compared between the colorimeter device and the spectrophotometer devices. All color space parameters obtained with the colorimeter were used as dependent variables to generate regression equations with values obtained from the spectrophotometers. The data was statistically analyzed to create predictive model between the reference and the target instruments through two methods. The first method uses linear regression analysis and the second method consists of partial least square regression (PLS) on each component. [Copyright &y& Elsevier]

An introduction to the journal is presented in which the editor discusses various reports in the issue on the topics including one on automotive industry, the other on perceptual factors for color composition and the third on tristimulus values.

The CIE defines chromaticity coordinates as the ratio of each of a set of three tristimulus values to their sum. As shown here, for two-equation systems such as 1964 ( u′, v′), there is always a tristimulus coordinate system that allows this definition to work. However, to include systems like that of MacLeod and Boynton in which three equations define chromaticity, an extension of the CIE definition would require a linear transformation that follows the ratio process. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 317-318, 2014; Published Online 20 December 2013 in Wiley Online Library (). DOI 10.1002/col.21863 [ABSTRACT FROM AUTHOR]