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The RGB-spectral conversion method has been used to quantitatively visualize proton diffusion phenomena that occur in a time on the order of 10 ms when an acidic ion-exchange resin is placed on an agar gel containing an acid-base indicator. The absorption spectra of the mixed indicator of bromothymol blue and methyl red were reproduced from two sets of color coordinates: RGB and L*a*b* values. We recorded a video of the color change of bromothymol blue–methyl red (BTB–MR)-containing agar gel in contact with the ion-exchange resin at a time interval of 10 ms. We successfully obtained the absorption spectra in a short time and predicted the pH values around the resin. Our results suggest that the spectral conversion method based on color coordinates has the potential for measuring the behavior of materials in nonequilibrium systems. Moreover, the present method would be one of the novel sensing technologies for the continuous monitoring of spectral change, which can be utilized as precise inline analysis. [ABSTRACT FROM AUTHOR]

We investigated the influence of cobalt (II) oxide additive in the amount of 1-3 mol.% on the structure and optical-color characteristics of chromium-containing glass with the following composition (mol.%): 29.6 Na2O; 19.7 B2O3; 49.3 SiO2; and 1.5 Cr2O3. The dependence of the optical-color characteristics of the glasses under study on the thermal treatment of the glass melt at a temperature of 10500C for 20 minutes was established. The thermal treatment resulted in the volumetric crystallization with the subsequent development of the aventurine effect. According to X-ray phase analysis data, the decorative effect was caused by Cr2O3 crystals. By using IR spectroscopy and differential thermal analysis, the structure of the experimental glasses was studied, and the influence of thermal treatment of glass melts on the formation of the structure of glass-ceramic material was established. Aventurine glass of dark blue-green color was obtained with a color tone λ=490 nm, color purity P=11.35%, and lightness L=5.454 %. The nature of the influence of cobalt (II) oxide on the optical-color characteristics of chromium-containing aventurine glass based on the Na2O-B2O3-SiO2 system is of interest for further development of new compositions of decorative ceramic glazes and enamel coatings. [ABSTRACT FROM AUTHOR]

Development of new non‐toxic pigments of a wide range of applications (from coloring of bone cements to aesthetic cosmetology, including tattooing) of blue and green shades is an urgent task. In the present work, colored compounds with apatite structure were synthesized by solid‐phase method. The obtained products were crystallized in hexagonal syngony of P63/m space group. The alloying elements – chromophores Mn5+ and Cr5+ in tetrahedrally coordinated positions – were responsible for sky‐blue and turquoise colors of the compounds, respectively. The conducted complex study (crystal structure, IR spectroscopy, color measurements, diffuse reflectance spectroscopy, electron paramagnetic resonance, cytotoxicity, surface morphology) of the colored compounds opens new opportunities for the development of alternative pigments of similar color range and expansion of the field of application of pigments based on compounds of apatite structural type. The results of in vitro study of cytotoxicity demonstrated the potential suitability of sky‐blue color compound (Mn‐containing apatite) for further creation of cold pigments on its basis for tattoo ink and bone cement coloring. [ABSTRACT FROM AUTHOR]

Development of new non‐toxic pigments of a wide range of applications (from coloring of bone cements to aesthetic cosmetology, including tattooing) of blue and green shades is an urgent task. In the present work, colored compounds with apatite structure were synthesized by solid‐phase method. The obtained products were crystallized in hexagonal syngony of P63/m space group. The alloying elements – chromophores Mn5+ and Cr5+ in tetrahedrally coordinated positions – were responsible for sky‐blue and turquoise colors of the compounds, respectively. The conducted complex study (crystal structure, IR spectroscopy, color measurements, diffuse reflectance spectroscopy, electron paramagnetic resonance, cytotoxicity, surface morphology) of the colored compounds opens new opportunities for the development of alternative pigments of similar color range and expansion of the field of application of pigments based on compounds of apatite structural type. The results of in vitro study of cytotoxicity demonstrated the potential suitability of sky‐blue color compound (Mn‐containing apatite) for further creation of cold pigments on its basis for tattoo ink and bone cement coloring. [ABSTRACT FROM AUTHOR]

Ti1-xSmxO2-x/2 (x = 0.025, 0.05, and 0.1) solid solutions with the anatase structure were synthesized by the precursor method and characterized by x-ray diffraction and scanning electron microscopy. Titanium glycolate Ti(OCH2CH2O)2 in which Ti was partially replaced by Sm was used as the precursor. The Ti1-xSmxO2-x/2 solid solutions exhibited intense reddish-orange luminescence at room temperature upon excitation at 350 nm. The luminescence properties of the compounds were due to f5-intraconfigurational transitions of Sm. The highest luminescence intensity was achieved for Ti1-xSmxO2-x/2 with x = 0.05. The chromaticity coordinates and correlated color temperature values were close to those typical of red phosphors. [ABSTRACT FROM AUTHOR]

New photoluminescent materials have numerous possibilities in many different areas from technological applications to contemporary glass art and design, encouraging the development of new forms and products. Glass luminescent materials, known for their exceptional durability and recyclability, position glass as an ideal solution for fostering a more sustainable future. In recent years, white luminescence in glass and ceramics has been the subject of several investigations about its possible application in white light‐emitting diodes (WLED). Color coordinates and CIE chromaticity diagrams serve as valuable tools to represent and define the range of luminescent colors achievable in a particular composition. These aid in understanding wheter a composition can be used to produce white luminescence or various other colors. In this study, a soda‐lime silicate glass composition was doped with a mixture of different lanthanide oxides to increase the luminescence color palette. The same glass sample can also present different colors by changing the excitation light, allowing higher tunability of luminescent colors. It was effectively demonstrated the extensive spectrum of colors produced, which was represented through luminescence color coordinates for all synthesized glasses. Moreover, the possibility of detecting if an excited state process is occurring was studied by calculating the lanthanides factors and comparing them with those used in the glass synthesis. Nevertheless, it is shown that the energy transfer process has to be significant to influence the color coordinates and the calculation of the factors. [ABSTRACT FROM AUTHOR]

For wide gamut backlight display application, main problems of CsPbX 3 (X = Br/I, I) quantum dots (QDs) glasses as red emission materials are too long emission wavelengths, low luminescence intensity and worse uniformity. The full width at half maximum (FWHM) and decay time should also be considered. Here, Ni2+ doped CsPbX 3 (X = Br/I, I) QDs in borogermanate glasses have been successfully fabricated by melt quenching and heat treatment. Transmittance, absorbance, photoluminescence (PL), PL excitation (PLE), PL decay and PL temperature characteristics are measured. By Ni2+ doping in the CsPbX 3 (X = Br/I, I) QDs glasses (QDGs), PL intensity is significantly improved to higher level of 106–107 counts (enhanced by 1.6–1.7 times). The peak wavelength is adjusted to suitable range of 630–650 nm by double anion CsPb(Br/I) 3 QDs. The uniformity is greatly improved by using suitable composition and concentration of CsPbX 3 (X = Br/I, I) QDs. In addition, the FWHM of 32–46 nm is sufficiently narrow. The PL decay shows sufficiently short lifetime of less than 100 ns. The PL temperature dependence fitting shows large exciton binding energy 376–400 meV. For wide color gamut display application, we have used three primary colors with the standard blue, green and red lights in NTSC standard, and the red light has been replaced by using perovskite CsPbX 3 (X = Br/I, I) QDGs. For the perovskite CsPbX 3 (X = Br/I, I) QDGs emitted at 667 nm and 644 nm, the color gamut area has been increased by 11% and 9%, respectively. The results indicate that the red light QDG materials can be applied to wide color gamut display. [ABSTRACT FROM AUTHOR]

Copyright of Chinese Journal of Liquid Crystal & Displays is the property of Chinese Journal of Liquid Crystal & Displays and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the present study, colored compounds with an apatite structure of compositions Sr 5 (P x V y Cr z O 4) 3 F (x + y + z = 1.0) were synthesized using a solid-state method. All compounds, except when z = 0.0, were colored in different shades of green. P5+ and V5+ ions are not coloring ions, so the color varied depending on the amount of Cr5+. A comprehensive analysis of the structures of the newly synthesized ternary solid solutions was conducted, and the crystallographic boundaries of the isomorphous mixture were refined. The reliability factors obtained from the refinement demonstrate that the ternary solid solutions crystallize in a hexagonal symmetry, space group P 6 3 / m. The pentavalent P, V, and Cr ions occupied equivalent tetrahedrally coordinated positions in the structure. The bond lengths in the tetrahedral positions are distorted more as the content of the pentavalent ion with a larger radius increases. The conducted comprehensive investigation (crystal structure, infrared spectroscopy, color measurements) of the colored compounds with an apatite mineral structure of compositions Sr 5 (P x V y Cr z O 4) 3 F (x, y, z = 0.0 to 1.0) opens up new possibilities for the development of alternative pigments and expands the application range of pigments based on similar materials. [Display omitted] [ABSTRACT FROM AUTHOR]

BaMoO4 was obtained via facile mechanochemical synthesis at room temperature and a solid-state reaction. An evaluation of the phase composition and structural and optical properties of BaMoO4 was conducted. The influence of different milling speeds on the preparation of BaMoO4 was explored. A shorter reaction time for the phase formation of BaMoO4 was achieved using a milling speed of 850 rpm. A milling speed of 500 rpm led to partial amorphization of the initial reagents and to prolongation of the synthesis time of up to 3 h of milling time. Solid-state synthesis was performed via heat treatment at 900 °C for 15 h. X-ray diffraction analysis (XRD), infrared (IR) and UV diffuse reflectance (UV-Vis) and photoluminescence (PL) spectroscopy were carried out to characterize the samples. Independently of the method of preparation, the obtained samples had tetragonal symmetry. The average crystallite sizes of all samples, calculated using Scherrer's formula, were in the range of 240 to 1540 Å. IR spectroscopy showed that more distorted structural MoO4 units were formed when the compound was synthesized via a solid-state reaction. The optical band gap energy of the obtained materials was found to decrease from 4.50 to 4.30 eV with increasing crystallite sizes. Green- and blue-light emissions were observed for BaMoO4 phases under excitation wavelengths of 330 and 488 nm. It was established that the intensity of the PL peaks depends on two factors: the symmetry of MoO4 units and the crystallite sizes. [ABSTRACT FROM AUTHOR]

In this study, cotton fabrics were dyed with different combinations of aluminum potassium sulfate (eco-friendly mordant), besides weld and madder as natural dyes. Then, the L*, a* and b* color coordinates were measured. The statistical analysis indicated that all three mentioned materials have significant effect on the color coordinates of the dyed fabric samples. In the next step, it was tried to model the relation between the concentration of mentioned materials and each color coordinate separately using regression method, artificial neural network (ANN), fuzzy logic and support vector machine (SVM). Moreover, in order to increase the models' accuracy, the genetic algorithm, particle swarm optimization (PSO) and gray wolf optimization (GWO) were applied to optimize the parameters of ANN, fuzzy logic and SVM. Mean absolute percentage error (MAPE) was calculated to assess the model's accuracy. It was revealed that the regression method indicates an acceptable accuracy only for L*, but the other models can predict all color coordinates with high accuracy. Finally, it was found that in prediction of L* and b*, ANN optimized with GWO presents the most accurate model with MAPE of 1.29% and 2.51%, respectively. While in the case of a*, ANN optimized with PSO possess the least MAPE (4.65%). [ABSTRACT FROM AUTHOR]

It was shown that the magnitude of fluctuating asymmetry can be used to assess the plant development stability. The shortcomings of the plant physiological state assessment were pointed out, both the visual one and that using the previously created colorimeter. (Research purpose) The study aimed to develop a device for determining the plant development stability by measuring the leaf color. (Materials and methods) The device was tested on cucumber plants grown under different spectra. The surface color was measured on the second and third leaves in the order of their emergence on the plant, to the left and right of the central vein: at the top of the leaf, at the bifurcation of the second veins of the second order, at the base of the leaf. During measurements, the device was brought to the leaf. The principle of the microcontroller-based colorimeter operation was described. (Results and discussion) The asymmetry of the values of the color coordinates of the symmetrical points on the cucumber leaf surface was found to be fluctuating and can be used to assess the plant development stability. The differences in the light environment quality, affecting the plant biometric parameters, are manifested in the asymmetry of the color coordinates of the symmetrical points on the leaf surface and the higher values of growth parameters (in plants under better light environment conditions) correspond to lower values of fluctuating asymmetry. (Conclusions) The developed colorimeter was proved to be compact and ergonomic, easy to manufacture, inexpensive, easy to operate and applicable to the field usage. The device enables to identify differences in the development stability of the plants grown under different light sources. The experimental conditions revealed that the fluctuating asymmetry values were 0.0301 relative units under LEDs and 0.0471 relative units under sodium lamps in the red range. In the green range they were 0.0228 and 0.0305, in the blue one 0.0253 and 0.0416 relative units, respectively.

Copyright of Horticulture / Kertgazdaság is the property of Herman Otto Intezet Nonprofit Kft. and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Scientists are increasingly interested in new inorganic luminescence materials that could be excited with near-infrared (NIR) radiation. These materials can be used as luminescent thermometers, bio-imaging agents, anti-counterfeiting pigments, etc. In this manuscript, we report the synthesis and investigation of optical properties of two series of K2Gd(PO4)(WO4):20%Tb3+ (KGPW): the first, KGPW:20%Tb3+ doped with 1–20% Eu3+, and the second, KGPW:10%Yb3+,20%Tb3+ doped with 1–20% Eu3+. The phase-pure specimens were prepared using a solid-state synthesis method. Down-shifting and upconversion luminescence studies have been performed using 340 and 980 nm excitation, respectively. For upconversion emission luminescence, Yb3+ ions were used as sensitizers in the KGPW phosphors. In these phosphors, Yb3+ ions absorb the 980 nm radiation and transfer the energy to Tb3+ ions. At his point, Tb3+ ions either emit themselves or transfer part or all of their energy to Eu3+ ions. It was observed that the emission color of the synthesized phosphors could be successfully tuned from the green to red by varying the Tb/Eu concentration ratio regardless of the 340 or 980 nm excitation. Such color change proves that one luminescent material (KGPW) can provide three colors (i.e., green, orange, and red). Herein, the optical properties, such as reflection, down-shifting excitation and emission spectra, upconversion emission spectra, fluorescence lifetime, thermal quenching, color coordinates, and quantum efficiency, were studied using steady-state and kinetic spectroscopy. [ABSTRACT FROM AUTHOR]

• ZnO/ZnS:Mn/GaN core–shell nanorods device was obtained using PLD and hydrothermal method. • The PL spectrum of ZnO/ZnS:Mn/GaN core–shell nanorods consists of four emission bands located at about 375, 450, 530 and 590 nm. • Under the forward bias, there are two luminescence bands located at 415 and 610 nm in the EL spectra. • The color coordinates of the EL spectra are very close to that of standard white light. ZnO/ZnS:Mn/GaN core–shell nanorods device was obtained by depositing ZnO/ZnS:Mn core–shell nanorods on GaN substrate using pulsed laser deposition and hydrothermal method. The optical properties of the device were studied. The PL spectrum of ZnO/ZnS:Mn/GaN consists of four emission bands located at 375, 450, 530 and 590 nm. The forward opening voltage is about 6 V. Under forward bias, there are two luminescence bands located at 415 and 610 nm, and the intensity increases with the increase of forward voltage. The color coordinates of EL spectra are very close to standard white light, indicating that the device has potential application in white light LED. Compared to ZnO/GaN nanorods device, the white light quality of ZnO/ZnS:Mn/GaN core–shell nanorods device is better, and it is more suitable as a long-term light source. [ABSTRACT FROM AUTHOR]

Textile finishing is the last stage to improve fabric aesthetic characteristic and impart functional properties, but at the same time it can produce some undesirable effects like shade change and variation in mechanical properties of fabric. These shade variations are undesirable and create major losses for the textile industry. These losses are related to rework and reprocessing of dyed fabric after finishing. To cope this issue, dyers are making decision on trial and error bases, therefore, this work has been conducted to quantify the shade change value. In this research work, an artificial intelligence-based system is developed to foresee the behavior of color before finishing. Color, shade percentage, finish type, finish concentration, and 31 reflectance values in the visible range 400–700 nm were selected as input for the training of artificial neural networks. The five networks were trained individually for the Δ color coordinates (△L, △a, △b, △C and △h). The networks were tested and cross-validated with 85% accuracy. The developed models were executed for the predictions of △L, △a, △b, △C, and △h with mean absolute errors 0.0765, 0.0869, 0.1528, 0.0829 and 0.1626, respectively. Mean absolute error values are showing a close correlation between actual and predicted values.

Copyright of Journal of Natural Fibers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Sea buckthorn (Hippophae rhamnoides L.) is consumed mainly in its processed form. Therefore, the investigation of the physicochemical properties of its berries is a current task in the aspect of food processing. The aim of this study was to determine the physicochemical parameters (soluble solid content, total titratable acidity, sugar/acid ratio), color characteristics (L*, a*, b*) and fatty acid profile of five varieties ('Askola', 'Clara', 'Habego', 'Leikora', 'Mara') and one Hungarian candidate, R-01, to establish a basis for experiments on the processability of the whole berries (e.g., drying). The weight of the berry of 'Leikora' (0.64 g) was significantly higher than the other investigated fruits. The differences between the values of soluble solid content (6.3–10.84 °Brix) and titratable acid (1.4–3.7%) content of berries were significant. 'Mara' had the highest sugar/acid ratio. Regarding the fatty acid profile, the amount of unsaturated fatty acids was measured between 72.6–83.4%, including polyunsaturated fatty acids, which were between 32.3–58.1%. The seeds of the tested samples contained high concentrations of linoleic acid (17.0–33.2%) and linolenic acid (15.3–24.9%), mainly in the case of the 'Mara', 'Clara' and 'Askola' varieties. Candidate R-01 could be used as a raw material for functional foods due to its significant content of palmitoleic acid and a favourable omega-6/omega-3 ratio. [ABSTRACT FROM AUTHOR]

Acanthamoeba keratitis is an aggressive and rapidly progressing ocular pathology whose main risk factor is the use of contact lenses. An early and differential diagnosis is considered the main factor to prevent the progression and improve the prognosis of the pathology. However, current diagnosis techniques require time, complex and costly materials making an early diagnosis challenging. Thus, there is a need for fast, accessible, and accurate methods for Acanthamoeba detection by practitioners for timely and suitable treatment and even for contact lens user as preventive diagnosis. Here, we developed a dual-mode colorimetric-based method for fast, visual, and accurate detection of Acanthamoeba using gold nanoparticles (AuNPs). For this strategy, AuNPs were functionalized with thiolated probes and the presence of target Acanthamoeba genomic sequences, produce a colorimetric change from red to purple. This approach allows the detection of 0.02 and 0.009 μM of the unamplified Acanthamoeba genome by the naked eye in less than 20 min and by color analysis using a smartphone. Additionally, real samples were successfully analyzed showing the potential of the technology considering the lack of point-of-care tools that are mostly needed. [ABSTRACT FROM AUTHOR]

Due to the effect of solution kinetics and crystallization kinetics of quantum dot (QD) during inkjet printing, the inkjet printing technique is prone to form coffee-ring patterns and in-homogenous films. Pioneering efforts are usually limited to mixed solvent or additive inks, in this paper, we investigated polymer QD films with good uniformity obtained by inkjet printing, in order to control the uniformity of quantum dot films in pixels, the mechanism of action of wettability science on inkjet printing was considered through the action of nitrous oxide (N2O) on the surfaces of substrates and banks. In the absence of N2O treatment, the inkjet-printed QD droplets would pile up and adhere to the bank walls due to capillary forces before the pinning process. With the N2O surface treatment, the contact angle of the QD ink on the substrate was increased from 16° to 62°. The wettability of the QDs between the substrate and the bank was reduced, and the side build-up phenomenon was significantly reduced. By changing the thickness of the QD film from 4.5 μm to 15 μm, the color coordinates of the spectrum were changed from (0.2320, 0.1556) to (0.1480, 0.6933).

The aim of this thesis is to achieve accurate discrimination and prediction of tomato growth period and color through hyperspectral techniques. The overall structure of the thesis is presented in the form of a graphical abstract, which is well-organized and easy to understand. In the research process, we first collected the hyperspectral information of tomato, which included the spectral data of the whole tomato and the spectral data of specific marker points (points precisely measured by using a colorimeter). For the hyperspectral information of the whole tomato, we used Principal Component Analysis (PCA) for feature extraction, and then applied algorithms such as Support Vector Machine (SVM), K-nearest neighbors (KNN) and Linear Discriminant Analysis (LDA) for classification prediction. The experimental results showed that the prediction accuracy of these methods could reach up to 93.1%, which demonstrated the effectiveness of hyperspectral information in tomato growth period discrimination. For the hyperspectral information of the marked points, we screened out the characteristic wavelengths that had a significant effect on tomato color prediction using the CARS and SPA methods. Subsequently, based on these characteristic wavelengths, we constructed predictive regression models such as partial least squares regression (PLSR), multiple linear regression (MLR), principal component regression (PCR) and support vector regression (SVR) for predicting the color parameters (L*, a*, b*, c, h) of tomato. Among all the constructed predictive regression models, we chose the model with the best performance by comparison and used it to generate the regression equation. Finally, combined with the pseudo-color image technique, we achieved a visual representation of tomato color, which provides a strong support for the rapid and non-destructive detection of tomato quality. [Display omitted] • Hyperspectral technology non-destructive detection of tomato growth period and color difference. • The highest recognition rate of the growth period classification model was 93.1 %. • The regression model of each color difference index has achieved good results. • Visualization of tomato color difference by pseudo-color image. Growth period determination and color coordinates prediction are essential for comparing postharvest fruit quality. This paper proposes a tomato growth period judgment and color coordinates prediction model based on hyperspectral imaging technology. It utilizes the most effective color coordinates prediction model to obtain a color visual image. Firstly, hyperspectral images were taken of tomatoes at different growth periods (green-ripe, color-changing, half-ripe, and full-ripe), and color coordinates (L*, a*, b*, c, h) were obtained using a colorimeter. The sample set was divided by the sample set partitioning based on joint X-Y distances (SPXY). The support vector machine (SVM), K-nearest neighbors (KNN), and linear discriminant analysis (LDA) were used to discriminate growth period. Results show that the LDA model has the best prediction effect with a prediction set accuracy of 93.1%. In addition, effective wavelengths were selected using competitive adaptive reweighted sampling (CARS) and successive projections algorithm (SPA), and chromaticity prediction models were established using partial least squares regression (PLSR), multiple linear regression (MLR), principal component regression (PCR) and support vector machine regression (SVR) Finally, the color of each pixel of the tomato is calculated using the optimal model, generating a visual distribution image of the color coordinate. The results showed that hyperspectral imaging can non-destructively detect tomatoes' growth stage and color coordinates, providing great significance for designing a tomato quality grading system. [ABSTRACT FROM AUTHOR]

[Display omitted] • Green light-emitting Ba 2 BiV 3 O 11 :Er3+ nanophosphors were synthesized via a solution combustion method. • The Rietveld Refinement technique explains crystal structure along with phase purity. • The detailed structural and photophysical analysis is done effectively. • Dexter's theory was utilized to examine the concentration quenching mechanism. • Significant application in various lighting devices, wLEDs, and latent fingerprinting applications. Monoclinic structure-based Er3+-activated Ba 2 BiV 3 O 11 nanophosphors have been developed via an easy and cost-efficacious urea-aided solution combustion (SC) procedure. Various spectroscopic and structural investigations thoroughly examine the produced powders. The crystal structure has been resolved by employing a combination of X-ray diffraction (XRD) and the Rietveld refinement practice. The developed powdered nanosamples are crystallized in a monoclinic crystal system with P21/a space group. Further, to evaluate the composition of elements and their relative distribution, energy dispersive X-ray (EDAX) analysis was performed. The band gap values for the host matrix and the optimal nanophosphors were measured using a DR spectrophotometer; the obtained values were 3.47 eV and 3.40 eV, respectively. The strongest excitation peak at 381 nm is closely-matched with the characteristic wavelength of commercialized near ultraviolet (NUV) based LEDs. The characteristic emission spectra of Ba 2 Bi 1-x Er x V 3 O 11 (x = 0.01–0.1) phosphors show the strongest emission at 553 nm (4S 3/2 → 4I 15/2). Additionally, photometric parameters such as quantum efficiency (86 %), color coordinates (x = 0.2568 and y = 0.4551), and correlated color temperature (CCT = 7722 K) are obtained from PL data and are strongly advised for use in wLEDs, color displays, imaging, lighting, and latent fingerprint applications. [ABSTRACT FROM AUTHOR]

Color, being one of the most important sensory characteristics, could be associated to the phenolic compound content and/or the antioxidant activity of fruits and vegetables. In this study, linear ordering was used to build quality rankings of red table grapes based on color parameters or phenolic compounds. First, the principle component analysis (PCA) was used to show the association between color of red grape skins (evaluated in CIE L*a*b* and L*C*h systems) and their individual phenolic compounds (investigated by the HPLC), total polyphenol content (TPC), total anthocyanins (ACNs), as well as the antioxidant activity (DPPH) of five table grape varieties. It could be observed that the lightness (L*) and hue angle (h) are the color coordinates strongly related to some phenolic compounds and ACN, whereas a* was related to DPPH and TPC. Five distinct clusters could be observed from PCA analysis with dark-colored grape varieties showing high levels of ACN (3.48–5.83 mg/g), low lightness (47.8–53.0), and high h values (353.7–359.8°). L*, a*, and h color coordinates were used to build table grape ranking. The second ranking was built based on phenolic compound content. Results of the two rankings were correlated. High Tau Kendall correlation coefficient (0.51, p = 0.000) indicated that linear ordering analysis, based on the simple color measurements, could be a useful tool for rapid screening of the quality of grapes. This could be valuable information for producers and consumers of the fruit making decision on the market. [ABSTRACT FROM AUTHOR]

Abstract Background To assess color compatibility between dental structures (human enamel and dentine) and three different types of ceramic systems. Methods Samples (1 and 2 mm-thick) of extracted tooth (containing dentine and enamel areas) and three ceramic systems with different shades and opacities (HT–High Translucent, T–Translucent) were prepared for this study: Vita Suprinity—VS (HT, T; A1, A2, A3, A3.5, B2, C2, D2) (Vita Zahnfabrik); Vita Enamic—VE (HT, T; 1M1, 1M2, 2M2, 3M2) (Vita Zahnfabrik) and Noritake Super Porcelain EX-3—NKT (A1, A2, A3, A3.5, B2, C2, D2) (Kuraray Noritake Dental). Reflectance measurements of all samples were performed over black backgrounds using a non-contact spectroradiometer (SpectraScan PR-670, Photo Research) under a CIE 45°/0° geometry. CIE L*a*b* color parameters were measured and CIELAB/CIEDE2000 color differences (ΔE00/ΔE* ab) and corresponding Coverage Error (CE) of ceramic system for dentine or enamel samples were calculated. Color data was analyzed using one-way ANOVA and post-hoc multiple comparisons tests. CE values were interpreted by comparisons with available 50:50% acceptability color threshold (AT) for dentistry. Results Statistically significant differences in lightness were found among all ceramic systems and human dentine (p 0.05) with VEHT. Thin samples (1 mm) of dentine and enamel showed significant statistical differences (p

A series of K2Bi(PO4) (MoO4) samples doped with 0.5%–50% Pr3+ was synthesized by a solid state synthesis method. The crystal phase was monitored by powder X-ray diffraction (XRD) and morphological characteristics were investigated by scanning electron microscopy (SEM). The luminescence properties: photoluminescence excitation and emission spectra, thermal quenching, and fluorescence lifetime values of Pr3+- doped samples were evaluated. The samples showed orange-red luminescence under near-UV excitation. It turned out that the profile of Pr3+ emission spectra is concentration and temperature dependent. Concentration quenching was observed in samples with higher than 1% Pr3+ concentration. Moreover, the calculated color coordinates showed good thermal stability in the 77–500 K temperature range. Based on the obtained results it can be concluded that prepared samples can be used in luminescent security pigments.

Scientists are increasingly interested in new inorganic luminescence materials that could be excited with near-infrared (NIR) radiation. These materials can be used as luminescent thermometers, bio-imaging agents, anti-counterfeiting pigments, etc. In this manuscript, we report the synthesis and investigation of optical properties of two series of K2Gd(PO4)(WO4):20%Tb3+ (KGPW): the first, KGPW:20%Tb3+ doped with 1–20% Eu3+, and the second, KGPW:10%Yb3+,20%Tb3+ doped with 1–20% Eu3+. The phase-pure specimens were prepared using a solid-state synthesis method. Down-shifting and upconversion luminescence studies have been performed using 340 and 980 nm excitation, respectively. For upconversion emission luminescence, Yb3+ ions were used as sensitizers in the KGPW phosphors. In these phosphors, Yb3+ ions absorb the 980 nm radiation and transfer the energy to Tb3+ ions. At his point, Tb3+ ions either emit themselves or transfer part or all of their energy to Eu3+ ions. It was observed that the emission color of the synthesized phosphors could be successfully tuned from the green to red by varying the Tb/Eu concentration ratio regardless of the 340 or 980 nm excitation. Such color change proves that one luminescent material (KGPW) can provide three colors (i.e., green, orange, and red). Herein, the optical properties, such as reflection, down-shifting excitation and emission spectra, upconversion emission spectra, fluorescence lifetime, thermal quenching, color coordinates, and quantum efficiency, were studied using steady-state and kinetic spectroscopy.

Featured Application: Methods for the reproduction of the color of translucent objects by printing structural color are the first steps in the generation of a 3D effect in 2D and 2.5D prints. They will find applications not only in decorative printing but also in security printing since they are hard to duplicate by standard methods. Unlike regular pigments based on selective light absorption, the so-called "effect pigments″ are based on the phenomena of structural color, or selective reflectance. Structural color has appealing aesthetic qualities, such as angle-dependent hue, and is able to produce lightfast colors. When used as a pigment, however, the gamut of the print is more limited, the color is difficult to measure, and therefore color management and preprint process become challenging. The aim of this paper is to compare the behavior of effect pigments in the processes of lithographic and screen printing with standard pigments used in so-called process inks, and to analyze their optical properties when used on their own or in combination with absorption pigments. An image of amber beads was printed as screen prints and lithographs. Three sets of inks were used: Set one: Standard process inks in the colors cyan, magenta, yellow and black (CMYK); set two: RGB inks formulated with Merck Spectraval™ pearlescent pigments which allow additive red, green, blue printing on a black substrate; and set three: golden inks formulated with pigments from the Merck Iriodin™ and Pyrisma™ effect pigment range. The image was printed on white and black paper. The optical appearance was assessed visually, and spectra and color coordinates were measured. [ABSTRACT FROM AUTHOR]

A generic red, green, and blue (RGB) LED system encompasses complex interactions of power, heat, light, and color, which pose a major challenge for achieving precise control over luminance and color-mixing in high-quality lighting applications. In this article, new nonlinear empirical models of a practical RGB LED system with closed-loop control are formulated. They enable precise prediction of luminous flux and color coordinates by using the three distinct reference voltages as the control variables for independent current regulation across the RGB LED strings. The proposed empirical models are experimentally verified by using a hardware prototype of a dc–dc single-inductor three-output LED driver with proportional–integral compensators and time-interleaving control scheme. The measured values of luminous flux and color coordinates agree closely with the predicted values from the models. [ABSTRACT FROM AUTHOR]

Sea buckthorn (Hippophae rhamnoides L.) is consumed mainly in its processed form. Therefore, the investigation of the physicochemical properties of its berries is a current task in the aspect of food processing. The aim of this study was to determine the physicochemical parameters (soluble solid content, total titratable acidity, sugar/acid ratio), color characteristics (L*, a*, b*) and fatty acid profile of five varieties (‘Askola’, ‘Clara’, ‘Habego’, ‘Leikora’, ‘Mara’) and one Hungarian candidate, R-01, to establish a basis for experiments on the processability of the whole berries (e.g., drying). The weight of the berry of ‘Leikora’ (0.64 g) was significantly higher than the other investigated fruits. The differences between the values of soluble solid content (6.3–10.84 °Brix) and titratable acid (1.4–3.7%) content of berries were significant. ‘Mara’ had the highest sugar/acid ratio. Regarding the fatty acid profile, the amount of unsaturated fatty acids was measured between 72.6–83.4%, including polyunsaturated fatty acids, which were between 32.3–58.1%. The seeds of the tested samples contained high concentrations of linoleic acid (17.0–33.2%) and linolenic acid (15.3–24.9%), mainly in the case of the ‘Mara’, ‘Clara’ and ‘Askola’ varieties. Candidate R-01 could be used as a raw material for functional foods due to its significant content of palmitoleic acid and a favourable omega-6/omega-3 ratio.

Ecofriendly exploration of Arjun bark (Terminalia arjuna) is a herbal natural colorant for cotton dyeing. This is because the demand for natural dyes has been increased worldwide due to their therapeutic usage and other food, textiles, agriculture, engineering, and medical applications. Therefore, this study has been carried out due to the isolation of colorant from Arjun bark in an acidified methanolic medium after exposure to ultrasonic rays up to 60 min. Additionally, using bio-mordants, it has been found that the application of 10% of Zeera (Cuminum cyminum) extract as meta-bio-mordant, 3% of Ilaichi (Elettaria cardamomum) extract as meta-bio-mordant, and10 % of Harmal (Peganum harmala) and Neem (Azadirachta indica) extract as meta-bio-mordants has given excellent color strength. These bio-mordants have not only made the coloration process more eco-friendly, viable, and greener, but also improved color strength with various tonal effects from red to reddish brown shades. Thus, it has been found that ultrasonic treatment as an environment-friendly tool has not only enhanced the color strength of natural colorant isolated from Arjun bark onto the cotton fabric under mild conditions. [ABSTRACT FROM AUTHOR]

Marigold (Tagetes sp.) is rich in health-promoting secondary metabolites like polyphenolic compounds and carotenoids. Though the marigold petals are excellent repository of natural pigments like carotenoids and natural antioxidants, enormous amount of dry biomass of marigold petals generated after usage is getting wasted. Thus, to utilize the marigold biomass generated effectively, there is a need of systematic study on level of natural antioxidants and pigments in diverse colored marigold petals. To address this issue, a study was conducted with the objective to determine the color coordinates, total phenolics (TPC), flavonoids (TFC), carotenoids, and in vitro antioxidant potential (AOP) in marigold flowers with varying petal colors ranging from off-white to deep orange. Significant differences were observed among the different marigold genotypes for their color coordinates, TPC, TFC, total carotenoids, and AOP. The TPC, TFC, and total carotenoid content ranged between 7.35–12.02 g GAE, 3.00–5.20 g CE, and 0.019–2.53 g βCE/100 g dry petal, respectively. Petal color is the prime-determinant of the carotenoids, petals with light to deep orange color had significantly high amount of carotenoids than the petals with off-white to yellow color. Color coordinate a* and Chroma were positively correlated with carotenoid content, and TPC was positively correlated with AOP measured in terms of both radical scavenging activity and reducing power, while TFC was positively correlated with AOP measured in terms of radical scavenging activity. To summarize, marigold flower petals can be commercially exploited as a source of natural phenolics with antioxidant potential for utilization in food industries in place of artificial antioxidant compounds. [ABSTRACT FROM AUTHOR]

Pumpkin (Cucurbita maxima), also called squash is a mass consumption fruit used in agroindustrial transformations to obtain new food products. This study aimed to evaluate the physical, physiological and physicochemical properties during a storage period of 42 days and the nutritional compounds of the freshly harvested fruit fractions. According to the CIEL*a*b* space, both the pulp and peel did not present significant changes in L* and a* values during the evaluated storage time; however, in the peel, a change in the b* values was evidenced. In addition, there was a decrease in the firmness of 10.8% in the fruit with peel and in the pulp, it was of 19.8% was observed, with a whole fruit weight loss of 2.33% and an average respiration rate of 6.9 mg CO2 kg-1h-1. According to physicochemical characteristics evaluated in the pulp, the values of pH, percentage of humidity, acidity, water activity and total soluble solids had no statistically significant changes occurred during the storage time. At the nutritional level, pumpkin is a good source of minerals, with a high concentration of potassium in all its fractions, and also has in total carotenoids (4.11±1.6 mg of β-carotene g-1 oven dry (o.d) in pulp and 6.24±2.7 mg of β-carotene g-1 (o.d) in peel). It was possible to conclude that the pumpkin has a low respiration rate, maintaining its physicochemical characteristics suitable for consumption throughout the evaluation period, presenting suitable conditions. [ABSTRACT FROM AUTHOR]

The trivalent rare‐earth (RE3+) doped phosphors show tremendous achievement in narrow band multicolor line emission for various applications. However, the 4f–4f absorption transition of these ions is forbidden in UV and blue light excitation. Usually, a sensitizer having spin allowed transition was used as a co‐dopant to excite these ions via the energy transfer phenomenon. Another approach promisingly using to excite these ions by efficient energy transfer from the intrinsic emission of the Ca2LuTaO6 double perovskite phosphors host lattice. Phosphors of Ca2LuTaO6 with double perovskite structure were synthesized by using a high‐temperature solid‐state reaction method. The produced Ca2LuTaO6 double perovskite phosphors show an intrinsic broad band emission centered at 424 nm under the excitation of 313 nm UV light. The origin of this broad band blue emission was deeply investigated by using computation and experimental approaches. The trivalent activator Dy3+ and Eu3+ were doped is a single and co‐dopant in the produced Ca2LuTaO6 phosphors to check their excitation in UV and near‐UV spectral region. X‐ray diffraction and scanning electron microscopy were used to investigate the structure and phase analysis. Various characterizations such as photoluminescence excitation, emission, and CIE chromaticity coordinates were measured which illustrate the potential of Dy3+ and Eu3+ activated Ca2LuTaO6 double perovskite phosphors for narrow band multicolor line emission for various applications. [ABSTRACT FROM AUTHOR]

ZnGa2S4 luminescent compound is prepared by solid‐state reaction, which is confirmed by X‐ray diffraction to have a tetragonal structure. The photoluminescence (PL) emission and excitation spectra, infrared (IR) reflectivity and Raman scattering of the defective ZnGa2S4 compound are studied experimentally. High stability of the shape and peak positions of the PL spectra is observed in a wide range temperature range (100–290 K). It was determined that PL intensity increases with decreasing temperature. Higher correlated color temperature (CCT) value >6000 K implies the suitability of using this material for light emitting diodes. Five modes of optical phonons are found in both IR reflectance and Raman spectra of ZnGa2S4 and identified from point group symmetry analysis. The calculations of the dynamic properties are carried out within the framework of the density functional theory (DFT) with full optimization of the lattice parameters. Results of calculations show that, the phonon‐dispersion curve is sensitive to S–Se replacement in ZnGa2S4 and gives rise to clearly pronounced energy gaps in the phonon spectrum. [ABSTRACT FROM AUTHOR]

ZnGa2S4 luminescent compound is prepared by solid‐state reaction, which is confirmed by X‐ray diffraction to have a tetragonal structure. The photoluminescence (PL) emission and excitation spectra, infrared (IR) reflectivity and Raman scattering of the defective ZnGa2S4 compound are studied experimentally. High stability of the shape and peak positions of the PL spectra is observed in a wide range temperature range (100–290 K). It was determined that PL intensity increases with decreasing temperature. Higher correlated color temperature (CCT) value >6000 K implies the suitability of using this material for light emitting diodes. Five modes of optical phonons are found in both IR reflectance and Raman spectra of ZnGa2S4 and identified from point group symmetry analysis. The calculations of the dynamic properties are carried out within the framework of the density functional theory (DFT) with full optimization of the lattice parameters. Results of calculations show that, the phonon‐dispersion curve is sensitive to S–Se replacement in ZnGa2S4 and gives rise to clearly pronounced energy gaps in the phonon spectrum. [ABSTRACT FROM AUTHOR]

Character display of automotive electronic gear lever is affected by LED lamp beads and transparent cover trim panel. The problems in the manufacturing processes include abnormal color coordinates, abnormal luminance value, and incomplete characters. The algorithm for rapid detection based on CMOS industrial cameras was proposed to replace manual visual inspection and improve abnormal recognition rate and detection efficiency. The color coordinates and luminance model for transient detection of the electronic gear lever were established through the temperature drift. The improved method of circle projection feature was used to achieve recognition. Curvature detection was used for incomplete detection of characters. The effectiveness was verified by experiments. Results show that high and low luminance weight traceability for color coordinate calibration has good consistency, and the luminance and gray values have an exponential relationship after the temperature drift of the characters. The method of circular projection feature has high robustness for the recognition of inclined and reduced character outlines. Curvature detection is effective for incomplete contours. The curvature steps of characters at different positions are six, four, and three, and the threshold is uniformly set to 0.15. The outflow rate of the problem electronic gear lever is reduced, and the productivity is increased by 0.3 percent with this detection method. This study provides a reference for the test platform of other types of electronic gear lever and rapid detection of characters. [ABSTRACT FROM AUTHOR]

In present work, five novel europium complexes [Eu(L)3·Phen (2), Eu(L)3·Bipy (3), Eu(L)3·Neo (4), Eu(L)3·Biq (5) and Eu(L)3·Batho (6)] were synthesized, derived from [Eu(L)3·2H2O] (1) complex by using ligand (HL) 5-hydroxy-2-(hydroxymethyl)-4H-pyran-4-one and coligands 1,10-phenanthroline, bipyridine, neocuproine, 2,2′-biquinoline and bathophenanthroline. In order to seek excellent photoluminescent properties, coligands were introduced in the complexes to form a rigid conjugated system, thus enhancing luminescence properties of complexes. The synthesized complexes reveal four narrow characteristic emission lines of Eu(III) consistent with 5D0 → 7FJ transitions, where J = 0, 1, 2 and 3 at about 580, 595, 614 and 650 nm, respectively. The 5D0 → 7F2 transition is responsible for strong red luminescence. Color coordinate diagram also indicates that x, y coordinates lie in deep red region. Thermal data are in favour of high thermal stability of synthesized compounds. Owing to their high thermal stability and strong red luminescence, these complexes might be used in fabrication of optoelectronic devices. [ABSTRACT FROM AUTHOR]

Color, being one of the most important sensory characteristics, could be associated to the phenolic compound content and/or the antioxidant activity of fruits and vegetables. In this study, linear ordering was used to build quality rankings of red table grapes based on color parameters or phenolic compounds. First, the principle component analysis (PCA) was used to show the association between color of red grape skins (evaluated in CIE L*a*b* and L*C*h systems) and their individual phenolic compounds (investigated by the HPLC), total polyphenol content (TPC), total anthocyanins (ACNs), as well as the antioxidant activity (DPPH) of five table grape varieties. It could be observed that the lightness (L*) and hue angle (h) are the color coordinates strongly related to some phenolic compounds and ACN, whereas a* was related to DPPH and TPC. Five distinct clusters could be observed from PCA analysis with dark-colored grape varieties showing high levels of ACN (3.48–5.83 mg/g), low lightness (47.8–53.0), and high h values (353.7–359.8°). L*, a*, and h color coordinates were used to build table grape ranking. The second ranking was built based on phenolic compound content. Results of the two rankings were correlated. High Tau Kendall correlation coefficient (0.51, p = 0.000) indicated that linear ordering analysis, based on the simple color measurements, could be a useful tool for rapid screening of the quality of grapes. This could be valuable information for producers and consumers of the fruit making decision on the market.

Background: To assess color compatibility between dental structures (human enamel and dentine) and three different types of ceramic systems. Methods: Samples (1 and 2 mm-thick) of extracted tooth (containing dentine and enamel areas) and three ceramic systems with different shades and opacities (HT–High Translucent, T–Translucent) were prepared for this study: Vita Suprinity—VS (HT, T; A1, A2, A3, A3.5, B2, C2, D2) (Vita Zahnfabrik); Vita Enamic—VE (HT, T; 1M1, 1M2, 2M2, 3M2) (Vita Zahnfabrik) and Noritake Super Porcelain EX-3—NKT (A1, A2, A3, A3.5, B2, C2, D2) (Kuraray Noritake Dental). Reflectance measurements of all samples were performed over black backgrounds using a non-contact spectroradiometer (SpectraScan PR-670, Photo Research) under a CIE 45°/0° geometry. CIE L*a*b* color parameters were measured and CIELAB/CIEDE2000 color differences (ΔE00/ΔE*ab) and corresponding Coverage Error (CE) of ceramic system for dentine or enamel samples were calculated. Color data was analyzed using one-way ANOVA and post-hoc multiple comparisons tests. CE values were interpreted by comparisons with available 50:50% acceptability color threshold (AT) for dentistry. Results: Statistically significant differences in lightness were found among all ceramic systems and human dentine (p < 0.001), while no significant differences were registered between enamel and VSHT, T and VEHT. 1 mm dentine showed no statistical differences with VST and VSHT for a* coordinate, while 2 mm dentine showed no significant differences (p > 0.05) with VEHT. Thin samples (1 mm) of dentine and enamel showed significant statistical differences (p < 0.05) for b* coordinate with less translucent materials (NKT, VET and VST). For dentine samples, none of the ceramic materials provided a CE lower than AT. VSHT provided the best CE for 1 mm-thick (CE00 = 1.7, CEab = 1.9) and for 2 mm-thick (CE00 = 2.3; CEab = 2.5) enamel samples. Conclusions: Color coordinates of evaluated esthetic ceramic systems were statistically different from those of human dentine in almost all cases. The evaluated ZrO2 lithium silicate glass–ceramic (VS), with its two levels of translucency, provided lower CE values with human enamel samples while conventional feldspathic ceramic (NKT) and hybrid ceramic systems (VE) demonstrated a better color compatibility with dentin samples. [ABSTRACT FROM AUTHOR]

In the field of display technology, the panels are mainly composed of pixels of three primary colors of red, green and blue, which have basically the same spectra in the same production batch due to the consistency of the production process. Thus, using commercially available color cameras to measure color coordinates of the panels is possible. However, actually the spectra of different panels of the same production batch or even different areas of the same panel are slightly different, which will lead to a certain error in principle. In this paper, we analyzed the effects of spectral shift of OLED panels on the accuracy of color coordinate measurement using simulated color camera response curve. We simulated multiple situations of different spectral shifts and then quantitatively analyzed the influence of spectral shift on the color coordinates based on the simulated color camera response curve and CIE1931 tristimulus values respectively. [ABSTRACT FROM AUTHOR]

Three ternary samarium(III) complexes with 6-methyl-4-oxo-4H-1-benzopyran-3-carboxaldehyde, 4-methyl-1,10-Phenanthroline, and 2,2′-Biquinoline and Bathocuproine have been prepared and characterized. The complexes exhibit crystalline character and excellent thermal stability. On irradiation with ultraviolet radiation, the complexes display characteristic emission peaks of samarium(III) ion. The color coordinates, decay curves, and quantum yield have been discussed in detail. The investigations demonstrate that the synthesized complexes might be practically useful in bio-assays, electroluminescent devices, and liquid lasers due to their fascinating optical properties. [ABSTRACT FROM AUTHOR]

A method to synthesize spinel (MgAl2O4)–based compounds doped with magnesium ions was developed, which makes it possible to create red-emitting phosphors (band peak at 651 nm) or green-emitting phosphors (band peak at 525 nm) due to the luminescence of Mn4+ or Mn2+, respectively, and also phosphors that have both (red and green) emission bands. Both types of luminescence exhibit quite high thermal stability; particularly, the green luminescence does. Namely, the temperature at which the luminescence intensity halves in comparison with the maximum intensity is T0.5 = 448 and 737 K for the red (Mn4+) and green (Mn2+) luminescence, respectively. On the other hand, for the phosphors that have both emission bands, the temperature dependences of the intensities of the red and green luminescence more closely resemble each other because of the energy transfer from Mn4+ ions to Mn2+ ions. Both emission bands are efficiently excited in the blue spectral region, which enables the use of the conventional three-color RGB (red–green–blue) method to create LED white-light sources based on a combination of a blue light-emitting diode and a phosphor containing manganese ions with an optimally chosen ratio between the intensities of the green and red emission bands. [ABSTRACT FROM AUTHOR]

Unlike regular pigments based on selective light absorption, the so-called “effect pigments″ are based on the phenomena of structural color, or selective reflectance. Structural color has appealing aesthetic qualities, such as angle-dependent hue, and is able to produce lightfast colors. When used as a pigment, however, the gamut of the print is more limited, the color is difficult to measure, and therefore color management and preprint process become challenging. The aim of this paper is to compare the behavior of effect pigments in the processes of lithographic and screen printing with standard pigments used in so-called process inks, and to analyze their optical properties when used on their own or in combination with absorption pigments. An image of amber beads was printed as screen prints and lithographs. Three sets of inks were used: Set one: Standard process inks in the colors cyan, magenta, yellow and black (CMYK); set two: RGB inks formulated with Merck Spectraval™ pearlescent pigments which allow additive red, green, blue printing on a black substrate; and set three: golden inks formulated with pigments from the Merck Iriodin™ and Pyrisma™ effect pigment range. The image was printed on white and black paper. The optical appearance was assessed visually, and spectra and color coordinates were measured.