Color Reproduction Research Articles

Influence of Heating Temperature on the Ink Transfer to Polymer Substrates in the Retransfer Printing Process

This study explores the effect of heating temperature on the ink transfer to Poly(vinyl chloride) and Poly(ethylene terephthalate) substrates in a specific retransfer printer. A notable correlation between heating temperature and solid color density was observed. The color density increases with heating temperature until reaching a critical threshold, typically around 140°C. Beyond this threshold, color density begins to decline due to ink penetration into the substrate, reducing ink film thickness on the surface of the substrates. This critical temperature is predominantly influenced by the properties of the ink rather than the characteristics of the substrate. The experimental study also reveals that variations in temperature-dependent ink transfer lead to noticeable color differences compared to standard references. An optimal temperature range of 120°C to 140°C was established, within which the process colors conform to the ISO 12647 standard, achieving DE values below 5. These results highlight the importance of maintaining appropriate ink transfer conditions to ensure precise color reproduction in printing processes.

Psychophysical Research on Color Appearance and Color Reproduction

Psychophysical Research on Color Appearance and Color Reproduction

Analysing Colour Shift effect of various Lamination Techniques on Coated Media using Offset Printing

Colour accuracy is the inevitability in every printing industry. Even minor deviations may impact severely in terms of print quality. Offset printing is widely used printing technique and also known for high quality production and efficiency also relies on precise colour reproduction in order to meet print quality expectations as per industry standards. Lamination and other post printing operations are common for embellishment to improve visibility aspects. In contrast, lamination technique cause colour shift in terms of colorimetric attributes which alters the appearance of printed colour significantly. This research is an attempt to analyze colour shift effect due to various lamination techniques on coated media printed by using offset printing. This research will explore the relationship between colour shift and lamination techniques while offset printing.

Evaluation of Color Difference Models for Wide Color Gamut and High Dynamic Range.

Color difference models (CDMs) are essential for accurate color reproduction in image processing. While CDMs aim to reflect perceived color differences (CDs) from psychophysical data, they remain largely untested in wide color gamut (WCG) and high dynamic range (HDR) contexts, which are underrepresented in current datasets. This gap highlights the need to validate CDMs across WCG and HDR. Moreover, the non-geodesic structure of perceptual color space necessitates datasets covering CDs of various magnitudes, while most existing datasets emphasize only small and threshold CDs. To address this, we collected a new dataset encompassing a broad range of CDs in WCG and HDR contexts and developed a novel CDM fitted to these data. Benchmarking various CDMs using STRESS and significant error fractions on both new and established datasets reveals that CAM16-UCS with power correction is the most versatile model, delivering strong average performance across WCG colors up to 1611 cd/m2. However, even the best CDM fails to achieve the desired accuracy limits and yields significant errors. CAM16-UCS, though promising, requires further refinement, particularly in its power correction component to better capture the non-geodesic structure of perceptual color space.

The Creative Watercolor Flow in the Digital Epoch: A Novel Approach to Cross-Disciplinary Aesthetics Integration

This article aims to explore the combination of watercolor and digital animation, analyzing how this interdisciplinary fusion expands the expressive boundaries of traditional art and enhances the artistic charm of digital animation. Firstly, it analyzes the current development status of watercolor and digital animation, pointing out their characteristics throughout history. Subsequently, it discusses in detail the application of watercolor techniques in digital animation, including the use of color, stroke simulation, and digital reproduction techniques for watercolor effects. In addition, a thorough analysis is conducted on the advantages and challenges of their combination, listing key elements and providing accurate assessments. Finally, it predicts future trends in the combination of watercolor art and digital animation, suggesting potential innovative directions. This study not only provides new creative perspectives for artists and animators but also offers theoretical support for the academic understanding of the possibilities and challenges of media integration in the digital age.

Color Characterization Model Using Subspace Polynomial Fitting Method for Modern Displays

ABSTRACT The prevailing color characterization model was established on the assumption of channel independence. However, modern displays did not typically exhibit good channel independence on color reproduction. With the emergence of modern displays, the computing performance of the existing characterization models is insufficient. In this study, we propose a subspace polynomial fitting model, constructing polynomial fitting relationships across one, two, and three channels respectively, based on the channel independence of the display to determine the division criterion of subspace (0, M, N, 255), which can form 64 combinations of training samples. The model outperformed existing models, with the maximum ∆E 00 color differences of the 777 tested combinations between the model predictions and the measurements across the seven displays ranging from 1.27 to 5.73. In addition, based on the subspace polynomial regression model, 4913 data sets of multilayer perceptron (MLP) neural networks can be constructed for reverse color characterization. Similarly, 777 tested combinations were calculated for seven displays, resulting in maximum color differences of 2.35 to 3.83 ∆E 00.

Analysis of the color-oversaturation problem in WCGDs and promising EOTF-based solution strategies

The gamut and EOTF (Electro-Optical Transfer Function) of a display together determine its color performance. Gamut determines the range of displayable colors, and the EOTF determines the color accuracy and depth. Image reproduction often comprises two parts: the image source and the display terminal. To ensure the universality of different terminals, the image source is generally produced in a standardized gamut standard, while the terminal pursues a wider gamut and more spectacular color performance. As a widely welcomed form of display, WCGDs (Wide Color Gamut Displays) boast stunning color performance. However, certain colors in WCGDs displays are oversaturated, which is unacceptable to the human eye. This paper analyzes the oversaturation problem of WCGDs. Firstly, a display model based on EOTF and gamut parameters is established. Then the color point vector field varies with EOTF is derived and the drift of luminance and chromaticity are analyzed separately. Finally, two strategies are present to optimize the color oversaturation problem of WCGDs based on the analysis conclusions and verify its effectiveness. This paper presents a detailed analysis and possible strategy for color oversaturation in WCGDs, providing a theoretical basis for the accurate color reproduction and efficient color management of WCGDs.

Color Reproduction of Chinese Painting Under Multi-Angle Light Source Based on BRDF

It is difficult to achieve high-precision color reproduction using traditional color reproduction methods when the angle is changed, and, for large-sized artefacts, it is also significantly difficult to collect a large amount of data and reproduce the colors. In this paper, we use three Bidirectional Reflectance Distribution Function (BRDF) modeling methods based on spectral imaging techniques, namely, the five-parameter model, the Cook–Torrance model and the segmented linear interpolation model. We investigated the color reproduction of color chips with matte surfaces and Chinese paintings with rough surfaces under unknown illumination angles. Experiments have shown that all three models can effectively perform image reconstruction under small illumination angle intervals. The segmented linear interpolation model exhibits a higher stability and accuracy in color reconstruction under small and large illumination angle intervals; it can not only reconstruct color chips and Chinese painting images under any illumination angle, but also achieve high-quality image color reconstruction standards in terms of objective data and intuitive perception. The best test model (segmented linear interpolation) performs well in reconstruction, reconstructing Chinese paintings at 65° and 125° with an illumination angle interval of 10°. The average RMSE of the selected reference color blocks is 0.0450 and 0.0589, the average CIEDE2000 color difference is 1.07 and 1.50, and the SSIM values are 0.9227 and 0.9736, respectively. This research can provide a theoretical basis and methodological support for accurate color reproduction as well as the large-sized scientific prediction of artifacts at any angle, and has potential applications in cultural relic protection, art reproduction, and other fields.

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.

Spectral-image-based lighting adaptive color reproduction of paper cultural heritages

An end-to-end image reproduction method is proposed to render cultural heritage images under arbitrary illuminating conditions. When displayed on a characterized display, the appearance of paper-based cultural heritages is reproduced as actually observed under the target illumination, by leveraging spectral images of the artworks and spectral power distribution (SPD) of the identical illumination. Psychophysical experiments are conducted to verify that the proposed method outperforms the traditional pipelines on reproducing real scenes, including the CIECAM02 color appearance model. The method has the potential to be applied in the digitization and exhibition of paper cultural heritages.

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.

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.

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.

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.