Color Reproduction Research Articles

Color Models in the Process of 3D Digitization of an Artwork for Presentation in a VR Environment of an Art Gallery

This study deals with the color reproduction of a work of art to digitize it into a 3D realistic model. The experiment aims to digitize a work of art for application in a virtual reality environment concerning faithful color reproduction. Photogrammetry and scanning with a LiDAR sensor are used to compare the methods and work with colors during the reconstruction of the 3D model. An innovative tablet with a camera and LiDAR sensor is used for both methods. At the same time, current findings from the field of color vision and colorimetry are applied to 3D reconstruction. The experiment focuses on working with the RGB and L*a*b* color models and, simultaneously, on the sRGB, CIE XYZ, and Rec.2020(HDR) color spaces for transforming colors into a virtual environment. For this purpose, the color is defined in the Hex Color Value format. This experiment is a starting point for further research on color reproduction in the digital environment. This study represents a partial contribution to the much-discussed area of forgeries of works of art in current trends in forensics and forgery.

Inkjet printing of mixed layers comprising multinary semiconductor quantum dots and charge transport materials for light‐emitting diode displays

AbstractQuantum dots (QDs) are important luminescent structures with applications in wide‐color‐gamut displays requiring exceptional color reproducibility. Multinary semiconductor QDs are expected to serve as eco‐friendly materials to replace conventional QDs owing to the narrow spectral widths and tunable bandgaps of these QDs. However, the application of multinary QDs, which tend to exhibit defect‐related emissions, to QD light‐emitting diode (QLED) displays will require electroluminescence to be obtained from QLEDs incorporating inkjet‐printed emitting layers. The present work examines QLEDs exhibiting vibrant color emissions based on blue‐emitting Zn–Se–Te QDs, green‐emitting Ag–In–Ga–S QDs, and red‐emitting Ag–Cu–In–Ga–S QDs. Each such QLED contains QD emitting layers comprising a mixture of charge transport materials. The spectra obtained from these RGB QLEDs fabricated by spin‐coating show very high color purity. Passive matrix QLED displays incorporating these QDs are also fabricated by inkjet printing to demonstrate the high color purity that can be obtained from multinary QDs in displays. In conjunction with passive matrix driving, these displays produce clear moving images with vibrant electroluminescence originating from the multinary QDs. The present results indicate that these QDs have significant potential for utilization in wide‐color‐gamut displays.

COMPARATIVE ASSESSMENT OF VISUAL COLOR MATCHING FOR ARTIFICIAL AND NATURAL TEETH BY STUDENT OF DENTAL FACULTY AT KHARKIV NATIONAL MEDICAL UNIVERSITY

The purpose of this study was to conduct a comparative assessment of dental students’ ability to match the color of patients’ teeth with aesthetic restorations. Materials and Methods. The study was conducted from 2021 to 2024 with participation of 2nd- and 3rd-year students at the Faculty of Dentistry, Kharkiv National Medical University, Kharkiv, Ukraine. Results. Accurate determination and reproduction of natural tooth color is a challenging task in aesthetic dentistry, as color plays a crucial aesthetic role. This process depends heavily on the experience and perception of dentists and can be approached subjectively (visual analysis) or objectively (special devices). Although shade determination is a routine task for dentists, errors are still common. The study revealed that 2nd-year students struggled significantly with color matching, especially for natural teeth, with error rates of 66.6% for artificial teeth and 80.8% for natural teeth, indicating a need for more training. Students performed better using the VITA Classic shade guide, which is simplified, but matching the color of natural teeth requires additional practice. The results confirm that clinical training improves students’ color-matching skills. After training, 3rd-year students showed a marked decrease in error rates: 35.8% for artificial teeth and 53.3% for natural teeth. The Vita 3D Master scale proved more accurate due to its broader color-matching capabilities. Overall, the accuracy levels improved significantly, highlighting the effectiveness of the training program. Conclusion. The results of the study demonstrate that training significantly improves students' ability to accurately determine tooth color. The 3rd year students who underwent clinical training showed better results in matching the color of both artificial and natural teeth, reducing the number of errors by 35.8% and 53.3%, respectively. The Vita 3D Master scale proved to be more accurate due to a wider selection of colors and more evaluation parameters. The 81.5% increase in the overall score confirms the effectiveness of the training in improving the accuracy of tooth color determination in the educational process.

Switchable Camouflage via Reflective Display

In nature, dynamic camouflage is performed by cephalopods and reptiles. Humans attempt to perform dynamic camouflage by employing display devices to show the surrounding background. In this work, a switchable camouflage device based on an electrophoretic display (EPD) is proposed. Color‐filter EPDs display colors by reflecting light through the color filters and black‐and‐white EPDs. The number of subpixels is found to be an important factor on color performance. To improve the poor saturation of color‐filter EPDs, the number of color filter subpixels is reduced. Compared with filters with three and four subpixels, a dual‐subpixel filter proposed in this work significantly improves the average saturation of red, green, and blue colors, with increases of 49% and 112%, respectively. Subsequently, the spectral characteristics of the color filter and black‐and‐white EPD are optimized by using genetic algorithm to reduce the average color difference between the display and the switchable target color, which can be reduced as low as 0.18. To visually demonstrate the color reproduction capability of the dual‐subpixel EPD, sample applications including the switchable vegetation and digital camouflages are designed and have a high degree of agreement with the background. In this work, an innovative and effective approach is introduced to dynamic camouflage.

Individual color matching functions from cross‐media color‐matching experiment

AbstractHuman color vision exhibits substantial variability, challenging the accurate measurement and reproduction of individual color appearances. This paper introduces a novel cross‐media color‐matching experiment that combines physical pigments and digital displays, providing a practical and efficient solution to measure individual color matching functions (CMFs). By using the Kubelka–Munk theory to synthesize broadband spectral pigments, optimized metameric pairs can be created to significantly differentiate categorical observers. Psychophysical experiment results reveal the superiority of specific CMFs for individual observers, surpassing standard models like the CIE 1931 2‐degree CMFs. This study also underscores the significance of employing CMFs for personalized color reproduction and explores the potential benefits of using higher bit‐depth displays, narrower‐band displays, and increasing repetition counts to enhance the accuracy of the color matching process.

Impact of Illuminant Metamerism on Colour Fidelity in Graphic Reproduction of Artistic Images

The aim of the research was to to evaluate the quality of illuminant metamerism by using Colour rendering index through similar paintings and half-tone reproduction images within the graphic industry. Employing the methodology of visual perception and testing conducted by standard observers, the study scrutinises how different colour techniques of paintings respond to diverse light sources under standardised conditions. This investigation is pivotal for understanding the chromatic fidelity and consistency of paintings and their reproduction with half-tone colours, by measuring the grey balance field, for all images. To find the most suitable light source and to complete the colour quality, the Osram LED light at 3000 K, 4000 K, and 6500 K is used. The resulting index could be deceptive in cases of significant disparities. The American IES TM-30-18 colour rendering index (CRI) metric, quantifies illumination metamerism's ability to faithfully depict natural colours. At every stage (R1–R15), the average colour reproduction CRI must be more than 90.

Quantitative analysis of the color accuracy and reproducibility in digital textile printing: Discrepancies within color reproduction media

In this study, the overall color reproducibility of a digital textile printing (DTP) process was investigated within a wide range of color gamuts, and the design color factors influencing color reproduction in the initial design stage of DTP were analyzed. During the DTP process, digital image samples, display samples, and fabric samples, each representing 1296 colors, were created. The color reproduction ranges of these samples and the discrepancies in their lightness, chroma, hue, and overall color were analyzed. It was found that the display samples exhibited the widest color reproduction range, particularly in terms of lightness and chroma. In contrast, the fabric samples showed the narrowest color reproduction range. Furthermore, it was shown that color reproducibility was significantly reduced when the medium transitions from display to fabric during the DTP process, with an average overall color difference of 24.34 Δ E*ab being detected between the display and fabric samples. The low color reproducibility of this DTP process was particularly influenced by the K ratio and the L*10 and C*ab,10 values of the initial design. More specifically, the K ratio and the L*10 value of the initial design imparted significant effects on the lightness reproducibility, whereas the C*ab,10 value of the initial design had a significant impact all on the lightness, chroma, hue, and overall color reproducibilities.

A comparative analysis of machine learning methods for display characterization

This paper explores the application of various machine-learning methods for characterizing displays of technologies LCD, OLED, and QLED to achieve accurate color reproduction. These models are formed from input (device-dependent RGB data) and output (device-independent XYZ coordinates) data obtained from three different displays. Training and test datasets are built using RGB data measured directly from the displays and corresponding XYZ coordinates measured with a high-precision colorimeter. A key aspect of this research is the application fuzzy inference systems for building interpretable models. These models offer the advantage of not only achieving good performance in color reproduction, but also providing physical insights into the relationships between the RGB inputs and the resulting XYZ outputs. This interpretability allows for a deeper understanding of the display’s behavior. Furthermore, we compare the performance of fuzzy models with other popular machine-learning approaches, including those based on neural networks and decision trees. By evaluating the strengths and weaknesses of each method, we aim to identify the most effective approach for display characterization. The effectiveness of each method is assessed by its ability to accurately reproduce and display colors, as measured by the ΔE00 visual error metric. Our findings indicate that the Fuzzy Modeling and Identification (FMID) method is particularly effective, allowing for an optimal balance between high accuracy and interpretability. Its competitive performance across all display types, combined with its valuable interpretability, provides insights for potential future calibration and optimization strategies. The results will shed light on whether machine learning methods offer an advantage over traditional physical models, particularly in scenarios with limited data. Additionally, the study will contribute to the understanding of the interpretability benefits offered by fuzzy inference systems in the context of LCD display characterization.

Impact of Substrate Material, Esthetic Material Thickness, and Cement on Color Reproduction in Implant-Supported Fixed Restorations.

Purpose This study aimed to evaluate the impact of substrate material, esthetic material type and thickness, and cement shade on the final color reproduction of implant-supported fixed restorations. The goal was to identify optimal combinations for achieving clinically acceptable esthetic outcomes. Material and methods An in vitro study was conducted using four substrate materials, hybrid polyetherketoneketone (PEEK)-based ceramic-reinforced polymer (BioHPP), chromium-cobalt alloy (CrCo), grade 5 titanium (Ti), and white zirconium oxide ceramic (WZirCAD), and three esthetic materials, lithium disilicate ceramic (e.max CAD), polymethyl methacrylate (PMMA), and zirconia oxide ceramic (e.max ZirCAD), at five different thicknesses (0.5, 1, 1.5, 2, and 2.5 mm). Color differences (ΔE*) were measured using a spectrophotometer, both with and without cement application. Statistical analysis was performed using the Kruskal-Wallis test and Bonferroni correction to assess the effects of material combinations on color reproduction. Results The study found that a 1 mm thickness of e.max CAD on BioHPP and CrCo substrates provided the best color matching, with ΔE* values closest to clinical acceptability. PMMA showed higher ΔE* values, indicating lower color stability compared to e.max CAD and e.max ZirCAD. Cement shade had a near-significant influence on final color perception, particularly with e.max ZirCAD on CrCo substrates. Conclusions The study suggests that using e.max CAD at 1 mm thickness on BioHPP or CrCo substrates provides superior esthetic results, underscoring the need for careful material selection in clinical practice. Further in vivo research is recommended to validate these findings and explore long-term outcomes.

Synergistic effect induces self crystallization of CsPbBr3 quantum dots in Borosilicate glass matrix By LiF

Cesium lead halide perovskite (CsPbX3) quantum dots (QDs) are recognized as viable substitutes for conventional fluorescent powder color converters, which can improve the color gamut and reproducibility of liquid crystal displays (LCDs). Encapsulating QDs in glass can effectively solve the water oxygen stability of QDs, but the glass matrix impedes the nucleation of QDs and the precipitation of QDs requires secondary heating. In our research, we successfully accomplished the self-crystallization of CsPbBr3 QDs facilitated by LiF within a B2O3-SiO2-ZnO borosilicate glass matrix.The results indicate that the self crystallization of CsPbBr3 QDs induced by LiF in borosilicate glass matrix has a synergistic effect. The Li+ ions can break the glass network structure and facilitate ionic migration and transport, while F- ions have good electronegativity due to ion aggregation, and can strongly attract Cs+ and Pb2+ ions with larger atomic radii, thereby promoting the rapid nucleation and growth of CsPbBr3 QDs, ultimately synthesizing QDs with uniform particle size, narrow half peak width, good optical properties, and thermal stability.

Inkjet‐printed quantum dot light‐emitting diodes: Development and challenges for display applications

AbstractQuantum dot (QD) technology is rapidly advancing and draws much attention for display applications where accurate and vibrant color reproduction is highly required. Currently, significant research is being conducted in developing quantum dot light‐emitting diode (QD‐LED) as next‐generation displays. QD‐LEDs offer several advantages, including high color purity, wide color gamut, and lower manufacturing costs. Recent advancements in QD synthesis and device engineering have significantly improved the performance of QD‐LEDs, but several challenges must be addressed for the successful commercialization. In this article, we provide an overview of QD‐LED developments and key issues that are required to be solved for realizing practical inkjet‐printed QD‐LED displays.

Monastic Color Reproduction: A Software Tool for Printing and Assessing the Monk Skin Tone Scale

Monastic Color Reproduction: A Software Tool for Printing and Assessing the Monk Skin Tone Scale

Textile color formulation methods: A literature review

AbstractColor has become an essential element in our communication and our judgment on products. In textile, the formulation of any color is an essential process to ensure color continuity from the master standard to all subsequent production batches. Indeed, the objective is to normalize its reproduction all along the color reproduction procedure. In the literature, researches concerning textile color formulation are important, so this review focuses on these different techniques and methods of color matching for dye mixtures and precolored fiber blends. This step involves determining the dyes or fibers to use (alone or in mixtures) and their appropriate proportions to reproduce the wanted colors. The main techniques used for dye mixtures are based on colorimetric, spectrophotometric, and artificial intelligence techniques. While for precolored fiber mixtures the used techniques are dived into theoretical and experimental models. In addition to the review of these different techniques, a quantitative analysis was carried out.

Analysis of Color and Artistic Conception in Painting Art

The charm of painting, as a bright pearl in the treasure house of culture, lies in its visual language constructed through colors and lines, which conveys the artist’s unique perception of life and profound emotions. Color, as the most intuitive and expressive language in painting, is not only a simple reproduction of material colors but also a projection of the artist’s inner world. Artistic conception, as a core concept in traditional Chinese painting theory, refers to the emotional atmosphere and spiritual mood embedded in paintings. The purpose of this paper is to discuss the interaction between color and mood in painting art, to analyze the techniques of using color in different painting styles and their influence on the creation of mood, and to provide new perspectives and methods for the creation of paintings.

Introducing a novel approach to dental color reproduction using AI technology.

This article aims to describe a systematic method for tooth color reproduction with ceramics restorations employing artificial intelligence (AI) software named Matisse. It provides a comprehensive analysis of the entire process, beginning with shade-taking and extending to ceramic application in a complex clinical case in the anterior region-specifically, a single central restoration supported by an implant. The clinical case presented highlights the potential of Matisse software for generating ceramic (inSync-Jensen Dental, USA) and staining (Miyo-Jensen Dental, USA) recipes over a zirconia abutment (Katana-Noritake Dental, Japan). This approach achieves an optimal single central restoration utilizing CAD-CAM and layering techniques. The systematic method employing the Matisse software achieved accurate color reproduction for a single central restoration supported by an implant. This result was achieved by the dental ceramist within the first attempt and without seeing the patient in the entire process. The Matisse AI-assisted protocol offers a systematic and scientifically grounded method for color reproduction in dentistry for indirect restorations.

Color-restoring and energy-saving imaging monitoring for intelligent offshore engineering

Images play a crucial role in artificial intelligence (AI) for offshore engineering, which provide a large amount of data for machine intelligence to ensure the safe operation and maintenance of offshore structures. However, due to the attenuation of sunlight in water or monitoring at nighttime, underwater imaging monitoring systems need a light source, which consumes a lot of energy and impacts the load capacity of an offshore monitoring system. In addition, due to the nonlinearity of attenuation at different wavelengths, underwater images generally suffer from color deviation, tending to be blue and green, which decreases the accuracy of machine learning and intelligent recognition in unmanned offshore engineering. In order to reduce energy consumption and enhance color restoration, we proposed and designed a three-detector underwater imaging system (TD&TP-UIS) based on a prism, in which three detectors were used to enhance the utilization efficiency of light, and a gated band coating was designed on the prism to enhance the color reproduction. A series of experiments were carried out in water tanks, pools, Qiandao Lake, and other places to verify the advantage of color restoration and energy saving using the TD&TP-UIS.

Spectral prediction method based on the transformer neural network for high-fidelity color reproduction

Color distortion often occurs during transmission and reproduction processes, and existing spectral prediction methods have the disadvantage of low prediction accuracy in halftone reproduction. Addressing this issue, this paper establishes a halftone dataset composed of four-color inks (CMYK) mixtures. Based on this, the transformer network is introduced to model and characterize the spectral features of mixed inks, and a forward color formulation prediction model and a reverse spectral prediction model combining halftone reproduction with spectral sequences are proposed, namely the spectrum-color transformer (SC-Former). Color reproduction quality assessment experiments are conducted using the dataset established in this paper and the international standard Ugra/Fogra Media Wedge V3.0 test set. The experimental results show that the SC-Former model outperforms traditional physical models and data-driven prediction models in terms of color reproduction effects and spectral prediction accuracy. This research contributes to the development of high-fidelity color reproduction techniques.

Research on the virtual design and implementation of colored glass for BIPV

In this study, we proposed a design and implementation method to display various high-saturation colors of Building Integrated Photovoltaics (BIPV) modules. The color reproduction results were compared and analyzed through simulations, using two methods, physical thickness and reflectance spectrum to reproduce RGB colors of Fraunhofer ISE’s (Germany) color BIPV module, a leading research institute. To achieve colored glass, a single-layer structure of Nb2O5 was simulated on the glass and deposited by the PVD sputtering method. Through this approach, we successfully produced an array of clear color glass. We performed simulations to attain RGB colors through a multi-layer structure model. We investigated the effects of key factors such as material, thickness, and the number of layers (SiO2, Si3N4, Nb2O5, TiO2) on reflectance and color attainment. Finally, assuming a color module deposited with a triple-layer structure of Nb2O5/SiO2/Nb2O5 was installed in a real building, the expected annual power generation was simulated and compared with the normal BIPV module.

Generic color correction for tone mapping operators in high dynamic range imaging.

One of the significant challenges in tone mapping is to preserve the perceptual quality of the tone-mapped images. Traditional tone mapping operators (TMOs) compress the luminance of high dynamic range (HDR) images with little to no consideration of image color information resulting into suboptimal colors. Existing color management algorithms require either manual parameter tuning or introducing lightness and hue shifts. The current study aimed to develop a color correction model in plausible agreement with the psychophysical phenomenon of color appearance perception for optimal color reproduction of tone mapped images. The proposed model leverages CIECAM16 perceptual correlates i.e., lightness, chroma, and hue. It is adaptive and entirely automatic while preserving the lightness of the tone-mapped image and maintaining the hue from the HDR image. Moreover, it does not require any gamut mapping correction algorithm in natural color reproduction. The effectiveness of the model was validated using objective and subjective methods. The experiments revealed that the model achieved optimal color reproduction in terms of the naturalness of the colors.

Comparison of Chromatic Assimilation Effects Depending on Printing Substrate in the Munker-White Model

Understanding the influence of paper surface structures on color perception is crucial for the printing industry. This research investigates the impact of horizontal and vertical parallel lines on chromatic assimilation using the Munker-White grid model. The study employs the perceived ∆E00 metric to quantify color differences and determine whether these textures affect perceived color accuracy and consistency differently. Results reveal variations in color perception due to surface textures. The biggest color difference (ΔE00) occurred at 60% RTV coverage for cyan, where the vertical structure showed a significantly lower value than the horizontal. For the yellow primary stimulus, the greatest difference was observed at 20% RTV coverage, with both structures showing high initial values that decrease with increased coverage. These findings provide valuable insights for improving color management practices and enhancing the quality and reliability of color reproduction on various substrates, contributing to advancements in printing technology and color science.