Color Management Research Articles

Externally Driven Nonlinear Time-Variant Metasurfaces

Resonant photonic nanostructures exhibiting enhanced nonlinear responses and efficient frequency conversion are an emergent platform in nonlinear optics. High-index semiconductor metasurfaces with rapidly tuned high-Q resonances enable a novel class of time-variant metasurfaces, which expands the toolbox of color management at the nanoscale. Here, we report on the dynamic control of the nonlinear optical response in time-variant semiconductor metasurfaces supporting high-quality factor resonances in the near-infrared spectral range. Pump-probe measurements of germanium metasurfaces at negative pump-probe time delays reveals frequency conversion in the fundamental beam and a blue-shift of 10~nm (3.05$\omega$) and 40% broadening in the third harmonic signal due to the photoinduced time-variant refractive index. A time-dependent coupled-mode theory, in excellent agreement with the experimental data, validated the time-variant nature of the system. Our findings expand the scope of time-variant metasurfaces and may serve as base for the next generation of nanoscale pulse shapers, optical switches and light sources.

Non-standard colorimetry in ICC colour management

In ICC v4 colour management, data is exchanged between different colour encodings via a fixed Profile Connection Space (PCS), in which colorimetry is based on the D50 illuminant, and the CIE 1931 standard observer. According to the ICC specification, colorimetry that is based on a different illuminant, or observer should be transformed into the fixed PCS; however, while a chromatic adaptation method is specified for when illuminants are different, there is no method specified for differences in observer. The Waypoint method has been proposed as a means of transforming between different colorimetric data encodings. In this study a Waypoint-based method recommended by ICC was evaluated as a mechanism for transforming into the ICC PCS, as applied to a use case in digital textile printing in which source colorimetry is based on the D65 illuminant and the CIE 1964 observer. It was compared with an alternative approach in which a non-ICC PCS was used within a conventional ICC colour management framework. The results show that when both source and destination colorimetry are based on D65/10-degrees, both methods perform equally well. However, when the source and destination colorimetry do not match, the ICC approach of transforming via the standard PCS yields better results.

RAW images and videos for 30K panoramic projection using the ACES workflow

According to our recent paper [1], the concept of creating a still image panorama with the additional inclusion of video footage up to 30K resolution has proven to be successful in various application examples. However, certain aspects of the production pipeline need some optimization, especially the color workflow and the spatial placement of the video content. This paper aims to compare two workflows to overcome these problems. In particular, the following two methods are described in detail: 1) Improving the current workflow with the Canon EOS D5 Mark IV camera as the central device, 2) Establishing a new workflow using the new possibilities of the Apple iPhone 12 Pro MAX. The following aspects are the subject of our investigation: a) The fundamental idea is to use the ACES as the central color management system. It is investigated if the direct import from RAW to ACEScg via dcraw and rawtoaces shows advantages. In addition, the conversion from Dolby Vision to ACES for the video processing is investigated, and the result is evaluated. Furthermore, the influence of stitching programs (e.g., PTGUI) on the color workflow is observed and optimized. b) The second part of the paper deals with the spatial integration of the videos into the still panoramas. Due to the different crop factors, specific focal lengths must be applied when using the Canon EOS D5 Mark IV; this distorts the image and video materials differently and makes it difficult to place the video footage in the panorama. We investigate if the usage of the lens distortion removal algorithm improves results. Furthermore, the comparison of the performance and capabilities of the Apple iPhone 12 Pro MAX is also evaluated regarding this aspect. Finally, the recorded resolution of detailed vegetation and foliage in video footage is compared. The paper summarizes the results of the new proposed workflow and indicates necessary further investigation. [1] Hasche, Eberhard; Benning, Dominik; Karaschewski, Oliver; Carstens, Florian; Creutzburg, Reiner: Creating high-resolution 360-degree single-line 25K video content for modern conference rooms using film compositing techniques. In: Electronic Imaging, Mobile Devices and Multimedia: Technologies, Algorithms & Applications 2020, pp. 206-1-206-14(14), https://doi.org/10.2352/ISSN.2470-1173.2020.3.MOBMU-206

Color Imaging XXVII: Displaying, Processing, Hardcopy, and Applications Conference Overview and Papers Program

Color imaging has historically been treated as a phenomenon sufficiently described by three independent parameters. Recent advances in computational resources and in the understanding of the human aspects are leading to new approaches that extend the purely metrological view of color towards a perceptual approach in documents and displays. Part of this perceptual view is the incorporation of spatial aspects, adaptive color processing based on image content, and the automation of color tasks, to name a few. This dynamic nature applies to all output modalities, including hardcopy devices, but to an even larger extent to soft-copy displays with their even larger options of dynamic processing. Spatially adaptive gamut and tone mapping, dynamic contrast, and color management continue to support the unprecedented development of display hardware covering everything from mobile displays to standard monitors, and all the way to large size screens and emerging technologies. This conference provides an opportunity to present, to interact, and to learn about the most recent developments in color imaging researches, technologies and applications. Focus of the conference is on color basic research and testing, color image input, dynamic color image output and rendering, color image automation, emphasizing color in context and color in images, and reproduction of images across local and remote devices. The conference covers also software, media, and systems related to color. Special attention is given to applications and requirements created by and for multidisciplinary fields involving color and/or vision.

An Exploration into Color Reproduction for Inkjet FDM Color 3D Printing

Advancing in inkjet fused deposition modeling (FDM) color 3D printing enables to create dedicated aesthetical appeal. However, the complete fabrication of a target color remains limited due to the unusual mismatch in 3D color management systems. In particular, the 3D aspect that makes the 3D color systems different from standard 2D printing, such as ink and substrate characteristics, viewing conditions, and base materials. Therefore, to the best of our knowledge, there is no suitable established method that supports color reproduction for inkjet FDM color 3D printing. In this paper, we analyze the color profile of an inkjet FDM color 3D printer to obtain a color model that could bridge the gap between a digital design (as an input) and the actual 3D printed results (as an output). We then created the color model by reproducing each color mapped to every possible color pair to determine the closest color between the target and printing colors on the basis of the color difference value, which can be rendered in lieu of the original printing colors. We verify our proposed color model by printing the mapped color and conduct a color measurement to compare it with the target colors. From the experimental results, we showed that our mapped colors can represent those desired by the user with an 80% success rate, which can be matched through controlled conditions.

The Amber Project: A Survey of Methods and Inks for the Reproduction of the Color of Translucent Objects

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.

A precise method of color space conversion in the digital printing process based on PSO-DBN

Neural networks have been widely used in color space conversion in the digital printing process. The shallow neural network easily obtains the local optimal solution when establishing multi-dimensional nonlinear mapping. In this paper, an improved high-precision deep belief network (DBN) algorithm is proposed to achieve the color space conversion from CMYK to L*a*b*. First, the PANTONE TCX color card is used as sample data, in which the CMYK value of the color block is used as input and the L*a*b* value is used as output; then, the conversion model from CMYK to L*a*b* color space is established by using DBN. To obtain better weight and threshold, DBN is optimized by a particle swarm optimization algorithm. Experimental results show that the proposed method has the highest conversion accuracy compared with Back Propagation Neural Network, Generalized Regression Neural Network, and traditional DBN color space conversion methods. It can also adapt to the actual production demand of color management in digital printing.

ИССЛЕДОВАНИЕ КАЧЕСТВА СИСТЕМ УПРАВЛЕНИЯ ЦВЕТОМ БУМАГИ

Paper color is one of the most important indicators of paper quality. Currently there is no information on functional color management systems. The study contains an analysis of information on the quality of color management on various paper machines for the production of printed papers. The research methodology consisted in the formation of a sample of numerical values of color coordinates in the CIE system from the archives of the APCS servers and laboratories of quality departments at factories. The analysis of the quality of operational control systems was carried out on the basis of the calculated histograms of the color coordinates of finished paper. The article presents the results of statistical processing of data about changes in the color coordinates L, a, b of the finished paper. Based on those results, the correlation of the dosage of chemical reagents and the color of the paper web is visible.

Sputtering‐Deposited Thin Films on Textiles for Solar and Heat Managements: A Mini‐Review

The application of magnetron sputtering technology in the functionalization of textiles has attracted increasing attention owing to its green nature. The thin films deposited on textiles provide additional opportunities for precise control of solar and heat flows by tuning the optical properties. In this review, the principles of color regulation, thermal management (including photothermal conversion and reflective insulation) properties, and simultaneous color and thermal management of sputtered thin films based on their interaction with solar radiation (visible and near‐infrared light) and thermal radiation are briefly summarized, and their research progress in textile coloring and thermal management as well as thermal management of colored textiles is reviewed. In addition, the challenging and future research of sputtered films on textiles for coloring and thermal management is briefly presented.

Developing test color samples to compute color fidelity of light sources for printing matter

Based on the clustering optimization of test color samples and a psychophysical experiment, the objective and subjective color fidelity of light sources for printing matter is evaluated, and an improved evaluation method thus has been proposed. Firstly, for representing the output characteristics of printing press, the International Color Consortium standard color target samples (ICC SCTS), which is measured in the process of color management, is used as a large color sample set. In a 6D spectral color space proposed in this paper, the optimized color sample set (OCSS) is obtained by Self Organizing Maps Neural Networks (SOMNN) clustering algorithm from ICC SCTS. Taking OCSS, ICC SCTS, and standard color sample set (SCSS) as the test color sample set, three objective color fidelity indexes (CFIs) CIE-Ra, Ra,2012, and CIE-Rf of 1202 light sources are calculated. The correlation metrics of the CFIs show that the OCSS highly improved the objective accuracy of color fidelity evaluation for printing matters. Secondly, in the psychophysical experiment, 20 observers have evaluated the visual color difference of the OCSS under the illumination of nine pairs of test and reference light sources. The subjective CFIs are calculated by using the visual color difference of OCSS obtained from the psychophysical experiment. In order to improve the subjective and objective consistency of CFIs, a polynomial modified model for objective color difference of OCSS is proposed. By the optimization of test color samples and the modification of color difference calculation, the method developed in this paper can be effectively and conveniently applied to the subjective and objective evaluation of light source for printing matters.

Statistical evaluation of a Color Managed Digital Printing Workflow (CMDPW) consistency [4th C of CMW

The purpose of this applied research was to determine the Color Managed Digital Printing Workflow (CMDPW) consistency (4th C of the color management) over a period of time [100 days, (N = 100)]. The quality of digital color printing is determined by these influential factors: screening method applied, type of printing process, calibration method, device profile, ink (dry-toner or liquid-toner), printer resolution and the substrate (paper). For this research, only the color printing attributes such as the overall average color deviation [ACD, ΔE (2000)] and the solid ink density (SID) were analyzed to examine the CMDPW process consistency in a day-to-day digital printing operation. These are the color attributes which are monitored and managed for quality accuracy during the printing. Printed colors of the random sample size (n = 80) were measured against the GRACoL2013 standards to derive the colorimetric/densitometric values. Reference colorimetric values used in the analysis were the threshold deviations (acceptable color deviations) as outlined in the ISO12647-7 standards (GRACoL2013). A control charts analysis was applied for further determining the process (CMDPW) SID and ACD variation. The data collected were run through multiple software applications (MS-Excel/SPSS/Minitab) to apply various statistical methods. Analyzed data from the experiment revealed that the printed colorimetric values were in match (aligned) with the GRACoL 2013 (reference/target). Since the SID values of CMYK colors were in control throughout the process, this enabled the CMDPW to produce consistent acceptable color deviation (Average Printed ΔE (2000) = 2.978; SD = 0.437; Acceptable Threshold color deviation is ΔE (2000) ≤ 3.00).

Triple-layer remote phosphor structure: A potential packaging configuration to enhance both color quality and lumen efficiency of 6,000–8,500 K WLEDs

Abstract To achieve further enhancement in the lighting quality of white light-emitting diodes (WLEDs), this study proposed a packaging structure with three different phosphor layers, called triple-layer remote phosphor structure. This structure can provide an overall control over the light color distribution of WLEDs. The yellow-green-emitting CaAl2O4:Mn2+ phosphor and red-emitting CaMoO4:Eu3+ phosphor are used along with the original yellow-emitting YAG:Ce3+ phosphor to fabricate the triple-layer structure. The concentration of yellow-emitting YAG:Ce3+ phosphor is required to be decreased as the concentrations of other phosphors increase to keep the predetermined correlated color temperatures. The color rendering index (CRI) and the color quality scale (CQS) are measured to reach a thorough color quality assessment for WLEDs. The color management can be achieved by adjusting the concentration of red-emitting CaMoO4:Eu3+ phosphor to enhance the red emission. In addition, adjustment of the concentration of yellow-green-emitting CaAl2O4:Mn2+ phosphor can result in higher luminous efficiency owing to its control over the green light components. Higher CRI is observed when CaMoO4:Eu3+ concentration increases, while an increase in CaAl2O4:Mn2+ phosphor leads to much lower CRI. The CQS – on the other hand – is remarkably high when the CaMoO4:Eu3+ concentration range is about 10wt%–14wt%, regardless of the proportion of the CaAl2O4:Mn2+ phosphor. Furthermore, 40% enhancement in luminous efficiency is also achieved since light scattering is minimized by the boosted green-light emission spectra. Manufacturers can take these findings as reference to fabricate high-quality WLED lights that fulfill all their requirements.

경상북도 영천시 농촌 중심지 활성화를 위한 경관색채가이드라인 연구

It is intended to present examples of improvement of urban landscape design through the landscape color strategy of Yeongcheon-si, Gyeongsangbuk-do, a city centered on rural areas. This study would like to propose improvements to the underdeveloped urban facilities and the old street scenery, which are common problems of rural cities. It is hoped that the image brought by the change in color will give vitality to the region, and that the lives of residents will be greatly improved in quality. First of all, prior to the study, a survey and analysis of the color status of Yeongcheon-si, Gyeongsangbuk-do, were preceded. In addition, a opinion survey was conducted on the unique color of Yeongcheon-si, and through it, i tried to understand how the city image was formed. In earnest, the color strategy was formed and the representative colors of the landscape reflecting the regional characteristics of Yeongcheon were extracted. Then, keynote colors and guidelines for color display were presented and regional concepts and processes were constructed. This study also attempted to consider color planning, color management, and subsequent management, including systems for each element. It is expected that urban landscape colors reflecting citizens’ emotions on the basis of the humanities environment will be able to more effectively represent regional characteristics. In particular, color images suitable for spatial characteristics were applied to each region, such as the northern Bohyeon Forest area, the eastern Nakdongjeongmaek area, the central urban area, and the western Palgongjimaek area. While forming such a unique color space, it is expected that a unified image of Yeongcheon-si can be obtained by giving continuity to the basic colors. It is expected that more beautiful urban regeneration will be possible by setting detailed guidelines to create an attractive street by giving Yeongcheon-si a pleasant urban image. Through this study, I hope that the appropriate use of urban landscape colors reflecting regional characteristics will be achieved along with the understanding of humanities and natural environments, not indiscriminate application of urban landscape.

퍼스널 컬러 자가진단이 네일 컬러 관리에 미치는 효과

This study aims to increase the effectiveness of nail color management through the self-diagnosis of one's personal color. As color becomes more important in the age of sensibility, color selection is becoming more important in nail art, and a color that suits you can express clean skin, healthy beauty, and your personality and image, so choose a nail color that suits you. It is very important to do it (Yoo Seon-jin, 2006). An online questionnaire was circulated among women, focusing on color during nail care. The survey was conducted over 31 days, from July 14, 2021 to August 15, 2021, and a total of 247 copies were used as data for final analysis. According to this study, the satisfaction with nail color management associated with personal color is high, and the difference in satisfaction with nail color management with personal color self-diagnosis was most prevelent in summer cool tones (M=3.80). Therefore, in the future, the development of a personal color self-diagnosis system that can be easily performed by individuals and research on nail color management using the personal color self-diagnosis system have been studied extensively, and nail color management using the personal color self-diagnosis system has become more common. It is hoped that nail color management will be more effective in the future.

Impact of a Transparent Coating on the Reflectance of a Line Halftone Pattern

Many prints are coated to increase their resistance or to enhance their appearance. Applying a smooth transparent layer on a print darkens and saturates its color, an easily observable effect which can be predicted in order to obtain better color management of coated surfaces and ink saving. A model was thus developed which describes the reflectance of a single-ink line halftone in optical contact with a transparent smooth coating. It is based on the peculiar way light diffuses inside the coating layer, a phenomenon called the “halo effect”. The model was compared to two experiments conducted at different scales where line halftones were coated with different coating thicknesses. The experiments enabled us to identify and measure the darkening effect caused by a coating layer, and validated the model.

Multifunctional leather surfaces coated with nanocomposites through conventional and unconventional methods

In this paper we present the results obtained by depositing the nanocomposite materials based on nano TiO2/TiO2:N, Ag, SiO2, single-walled carbon nanotube (SWCNTs), single-walled functionalized carboxylic acid, (SWCNT-COOH), poly(2,2′ bithiophene) (PBTh) and poly(dipheylamine) (PDPA) by conventional and unconventional methods on the surface of sheepskin leathers. The nanocomposite materials were integrated in film forming polymers and were applied on sheepskin leather surfaces by spraying (conventional method) or by activating the surface with cold atmospheric plasma followed by electrospraying (unconventional methods). The leather surfaces were tested for antimicrobial properties against Gram-positive and Gram-negative bacteria and fungi according to ISO 20743: 2007. The photocatalytic properties under visible light exposure were also tested using two organic stain models (methylene blue and orange II). The stain discoloring was evaluated by measuring the color differences between the blank and the samples with DATA Color Check Plus II portable device assisted by CIELab color management software. The evaluation of the physical–mechanical resistance and comfort properties for the sheepskin leathers was determined by measuring the water vapor permeability, rubbing tests and abrasion resistance. The results showed that the sheepskin leather surfaces treated with nanocomposite materials have improved antibacterial, self-cleaning, physical–mechanical and comfort properties as compared to untreated samples, with potential applications for added value multifunctional products.

DIGITAL COLOR REPRODUCTION AND DOCUMENTATION OF OIL PAINTING USING IMAGE PROCESSING

Abstract. Digital photography is a method easily employed to capture images. Mobile devices such as smartphones and tablets as well as dedicated cameras are used to capture images. Furthermore, as hardware continues to improve, the resolution of images in 100 MP and 8K videos has recently been increased, and the quality of images enhanced through various types of image processing software. However, because the focus of photography is to record a moment activity, recording the orginal color of subject has been pushed back from priority. Digital photographs of cultural heritage are mainly captured for aesthetic appreciation and database construction. Those images for the purpose of the latter should record the exact color and shape of the subject. However, the theoretical approach of this is difficult and relatively complex procedures are able to create images that differ from the original color. Thus, it means falling in value that culture heritage data of important for color conservation. Various attempts have been made throughout the industry to capture the original colors of the subject accurately. The color management system (CMS) is a typical method of such. In this study, digital color reproduction and record studies were conducted on representative oil paintings of modern times in Korea. Accordingly, the light source’s color index and color temperature were measured. Furthermore, a color recording environment was established and digital images were acquired. Subsequently, it was able to record the original color through CMS-based image processing. It is believed that this study will enable one to understand the production techniques of works through the color record of oil paintings and help one to monitor conservation conditions such as discoloration.

P‐7.3: A methodology of color management with saturation searching and color gamut remapping

Since OLED implement superior chromatic efficiency without the transmittance impact of color filter. Besides the benefit of higher brightness, excellent color saturation can perform wider factory gamut to be achieve several standard color spaces, which such as DCI‐P3[3] and adobe [2] of standard color space. For achieving AMOLED panel of display performance, this paper would like propose a methodology to utilize gamut remapping and adjustable saturation searching to pursue target chromatics coordinates in CIE‐xy. The uniform 48 color points are utilized to execute experiments to verify algorithmic performance with auto tuning software tool.

Research on color management of printing images on Bazhong specialty paper packaging

Research on color management of printing images on Bazhong specialty paper packaging

Technical and Scientific Imaging for Archaeological purpose – A Brazilian case.

This paper is about Technical and Scientific Imaging for caving painting (archeological site in Brazil). High quality imaging with color management has been used, in addition to scientific procedures to generate digital images, capable for recording not visible light (ultraviolet and infrared radiation). In addition, the RTI (Reflectance Transformation Imaging) technique was used. Rock Art is a kind of Cultural Heritage, extremely fragile archaeological remains and susceptible to a series of factors (physical, chemical, anthropic and others) that can cause different impacts for their preservation. The Rock Art can suffer an irreversible damage, which can greatly compromise research and relative studies, then, requiring great scientific and technical procedures for imaging.