Painting Method Research Articles

Fabrication of low-cost flexible thermoelectric generator using conductive HB graphite paint operated by solar radiation

Paper-based flexible thin film thermoelectric generators have emerged as a promising and feasible alternative to organic and inorganic conductors due to their ability to operate at room temperature within a limited temperature range. Here, a flexible solar thermoelectric generator (STEG) designed from a single material has been introduced, prepared by a simple painting method. We prepared HB graphite-based conductive paint and demonstrated a very unique method to design flexible STEG devices. The graphite paint shows p-type semiconductive behaviour, while, in conjunction with the polyethyleneimine (PEI) polymer, it acts as an n-type material. Based on the transport properties, the paint appears to be a good candidate for designing STEG devices. At room temperature, the power factor of 378 nW m−1 K−2 for p-type paint and 1.51 nW m−1 K−2 for n-type paint is obtained. In order to examine flexibility over the long term, the performance of the material was inspected through 300 repeated cycles, and transport properties (conductivity) were found to increase from 21 700 S m−1 to 73 500 S m−1 due to the excellent emulsifying properties of gum Arabic, which were confirmed by field emission scanning electron microscope analysis. To evaluate the performance of the thermoelectric (TE) generator, eight pairs of p–n legs are fabricated on normal copier (80 GSM) paper, and an output voltage of ∼0.1 mV K−1 (∼5.5 mV) for a temperature gradient T of up to ∼60 K was achieved. Further, the performance of flexible TE devices can be improved by increasing the number of thermoelectric legs and by sandwiching the device between Kapton tapes. Our work suggests a promising and simple approach to achieving cost-effective conversion of solar energy into electricity and highlights the potential of flexible STEGs for low-power applications.

Facile Synthesis of Carbon-Based Inks to Develop Metal-Free ORR Electrocatalysts for Electro-Fenton Removal of Amoxicillin.

The electro-Fenton process is based on the generation of hydroxyl radicals (OH•) from hydroxide peroxide (H2O2) generated in situ by an oxygen reduction reaction (ORR). Catalysts based on carbon gels have aroused the interest of researchers as ORR catalysts due to their textural, chemical and even electrical properties. In this work, we synthesized metal-free electrocatalysts based on carbon gels doped with graphene oxide, which were conformed to a working electrode. The catalysts were prepared from organic-gel-based inks using painted (brush) and screen-printed methods free of binders. These new methods of electrode preparation were compared with the conventional pasted method on graphite supports using a binder. All these materials were tested for the electro-Fenton degradation of amoxicillin using a homemade magnetite coated with carbon (Fe3O4/C) as a Fenton catalyst. All catalysts showed very good behavior, but the one prepared by ink painting (brush) was the best one. The degradation of amoxicillin was close to 90% under optimal conditions ([Fe3O4/C] = 100 mg L-1, -0.55 V) with the catalyst prepared using the painted method with a brush, which had 14.59 mA cm-2 as JK and a H2O2 electrogeneration close to 100% at the optimal voltage. These results show that carbon-gel-based electrocatalysts are not only very good at this type of application but can be adhered to graphite free of binders, thus enhancing all their catalytic properties.

‘Is that not Titian?’ Echoes of Venice in George Frederic Watts’s Self-Portraits, between Self-Fashioning and Artistic Practice

The reception of Venetian Renaissance painters had a profound effect on the creation of a British tradition of painting and played an important role in the development of the portrait as a typically British genre. This is precisely what this article aims to explore, through the emblematic case of the self-portraits of Victorian artist George Frederic Watts. Many of the artist’s self-portraits, in fact, explicitly engage with the tradition of Venetian art, and do so in multiple ways. On the one hand, the artist models himself on the figure of Titian, playing with the pose, the gesture, and the physical resemblance with the old master. On the other hand, Watts also aims at mastering the secrets of Titian’s painting method, which he discovered through the reading of ancient painting treatises. Thus, the relationship with the Renaissance plays a double role here, as it shapes the public and private image of the artist, but it also affects his artistic practice, and the very materiality of his paintings. This paper will also contextualize Watts’s ‘venetianism’ with that of Frederic Leighton, mid-Victorian photography, and the decadent painter Charles Ricketts, drawing a broader picture of the fascination with Venetian art in late 19th-century England.

Application of Information Integration Technology to Help Minority Traditional Arts in Chinese Painting Art Designs

Abstract This study utilizes the application of information fusion technology in the artistic design of Chinese paintings, especially exploring how to incorporate the elements of traditional ethnic minority art to enrich and develop the spatial aesthetic expression of Chinese paintings. The study first analyzes the differences in spatial artistic expression between Chinese and Western painting. It focuses on the spatial expression methods of Chinese painting and their application in ethnic minority traditional art. The mathematical model of minority art plane is constructed through the method of coordinate space and its transformation. The PAD emotional attribute model is used to quantitatively analyze the dynamic characteristics of Chinese painting art design works. The results show that the traditional elements of ethnic minorities incorporated in Chinese painting art design can effectively enrich the emotional expression of the paintings and enhance the aesthetic value of the art works. In 2022, the content of traditional elements of ethnic minorities in Chinese paintings increased by about 20 times compared with that in 2015, showing the increasing popularity of this art form. This study reveals the potential application value of information fusion technology in traditional art design and provides a new development direction for Chinese painting art design.

Application of Artificial Intelligence-based Visual Arts Pedagogy in Traditional Painting Education

Abstract Traditional art has a deep cultural heritage and rich connotation, combining artificial intelligence technology with traditional aesthetics as a way to realize the innovation of traditional painting education mode. In this paper, starting from the performance of traditional painting’s aesthetic value, a personalized intelligent painting teaching mode is constructed based on the visual art teaching method and combined with artificial intelligence. The CCME-GAN model is introduced for the construction of a personalized painting learning generation model, and the BERT-LDA model is established by combining the BERT model and the LDA model for the intelligent evaluation of personalized painting works. Xinjiang folk artworks were selected as the research data source to carry out the validation of personalized painting work generation and assessment, and teaching comparison experiments were designed to analyze the teaching effect of the personalized intelligent teaching mode. The subjective evaluation score of Xinjiang folk art paintings generated by the CCME-GAN model was 9.11, and among the nine clustering results of painting work assessment, the eigenvalues of the theme of painting evaluation of Cluster 1 range between [0,5.5]. At the end of the teaching experiment, students’ creativity scores increased from 2.74±0.37 before the experiment to 4.63±0.26. Relying on artificial intelligence technology can enhance the teaching effect of traditional painting methods and improve students’ painting levels.

Multicentric study on the reproducibility and robustness of PET-based radiomics features with a realistic activity painting phantom.

Previously, we developed an "activity painting" tool for PET image simulation; however, it could simulate heterogeneous patterns only in the air. We aimed to improve this phantom technique to simulate arbitrary lesions in a radioactive background to perform relevant multi-center radiomic analysis. We conducted measurements moving a 22Na point source in a 20-liter background volume filled with 5 kBq/mL activity with an adequately controlled robotic system to prevent the surge of the water. Three different lesion patterns were "activity-painted" in five PET/CT cameras, resulting in 8 different reconstructions. We calculated 46 radiomic indeces (RI) for each lesion and imaging setting, applying absolute and relative discretization. Reproducibility and reliability were determined by the inter-setting coefficient of variation (CV) and the intraclass correlation coefficient (ICC). Hypothesis tests were used to compare RI between lesions. By simulating precisely the same lesions, we confirmed that the reconstructed voxel size and the spatial resolution of different PET cameras were critical for higher order RI. Considering conventional RIs, the SUVpeak and SUVmean proved the most reliable (CV<10%). CVs above 25% are more common for higher order RIs, but we also found that low CVs do not necessarily imply robust parameters but often rather insensitive RIs. Based on the hypothesis test, most RIs could clearly distinguish between the various lesions using absolute resampling. ICC analysis also revealed that most RIs were more reproducible with absolute discretization. The activity painting method in a real radioactive environment proved suitable for precisely detecting the radiomic differences derived from the different camera settings and texture characteristics. We also found that inter-setting CV is not an appropriate metric for analyzing RI parameters' reliability and robustness. Although multicentric cohorts are increasingly common in radiomics analysis, realistic texture phantoms can provide indispensable information on the sensitivity of an RI and how an individual RI parameter measures the texture.

Символический капитал авангарда в дискурсе неофициального искусства 1960–1980-х гг.

The article considers the work of independent artists of the 1960s and 1980s, rethinking the heritage of the avant-garde. In the unofficial art discourse, the ideas of the beginning of the XX century represent symbolic capital, significant for artists in the formation of new techniques. The appeal to the avant-garde tradition unites various regional schools of non-conformism in an effort to create a synthesis of contemporary artistic practices and art of the past. Unofficial art unites representatives of different disciplines, were separated from public ac-tivities due to long censorship. The creative and conceptual searches of the artists expressed a disconnect be-tween personal, emotional and inner world of artistic thinking in the late 1950s, tired of operating a single sys-tem. The appeal to the avant-garde tradition unites various regional schools of non-conformism in an effort to create a synthesis of contemporary artistic practices and art of the past. Moscow nonconformists developed a conceptual direction, representatives of the Leningrad underground experimented with methods of metaphysi-cal painting and abstract art, ideas of decorative symbolism were preserved in the works of Saratov noncon-formists. Interacting with the avant-garde, nonconformists form a unity of figurative and abstract painting, a dis-tinctive feature of unofficial art.

FISH painting for chromosome identification of aneuploid cauliflower (Brassica oleracea L. var. botrytis)

A common problem in the cultivation and breeding of cauliflower (Brassica oleracea L. var. botrytis) is the occurrence of aneuploids in offspring families. To reveal the chromosomal cause of such numerical variants, it was necessary to develop karyotype tools with which chromosomes can be easily identified. Since mitotic chromosomes in this crop are morphologically similar and lack differentiating banding patterns, we tested two Fluorescent in situ Hybridization (FISH) procedures for chromosome identification: (1) FISH painting with diagnostic repetitive DNA patterns and (2) cross-species chromosome painting. The first method consists of a five-colour FISH with 5s rDNA, 45S rDNA, and two Brassica rapa centromere-specific repeats, and a B. rapa BAC (KBrH092N02) containing a dispersed repeat of an unknown class. The second method is an advanced FISH technology based on hybridising DNA probes of a related species under adapted stringency conditions to identify their homoeologous loci. To this end, we applied four pools of BACs from Arabidopsis thaliana in a multicolour FISH for a banding pattern on the chromosomes of cauliflower (Brassica oleracea L. var. botrytis). Due to the genome triplication and various chromosome rearrangements of Brassica oleracea compared to Arabidopsis, we used MUMmer whole-genome alignment plot information to select Arabidopsis BAC pools with which all cauliflower chromosomes could be identified. In a sample of 21 plants with aberrant phenotypes, we demonstrated primary trisomy for chromosomes 1–6 and 8, and telo-trisomy for chromosomes 7 and 9. Finally, we discuss the advantages and drawbacks of the two painting methods and eventual alternatives for demonstrating numerical aberrations in the cauliflower populations.Graphical

Similarity detection method of science fiction painting based on multi-strategy improved sparrow search algorithm and Gaussian pyramid

Similarity detection method of science fiction painting based on multi-strategy improved sparrow search algorithm and Gaussian pyramid

‘不俗’의 심미성 추구

This study aims to examine the aesthetic value of ‘non-vulgarization(不 俗)’ contained in the creation and criticism of landscape paintings pursued by Han Zhuo’s Shanshuichunquanji(2011), Huizong(徽宗) Xuanhe(宣和) 3rd year of the Northern Song Dynasty. The concept of ‘elegant and vulgar(雅 俗)’ was put to use as an evaluation language. The value of ‘nonvulgarization’ emphasized the expression of intention in the creation of poems, calligraphy and painting by literary men, and pursued natural and plain beauty. In comparison, Han Zhuo pursues ‘non-vulgarization’ by emphasizing the old law in order to proceed to Tao in painting. Han Zhuo expressed not only the cultivation of learning but also the replacement of poetry with a painting’s implied meaning and the proficiency of brushing, Furthermore, he emphasized “learning” in order to have a sophisticated aesthetic with the Confucian method. Despite the fact that the literary men at the time considered that the character of the painting was congenital and could not be learned as a manifestation of personality due to social status, Han Zhuo believed that the aesthetics of “non-vulgarization” for landscape painting could be achieved by learning, learning the method of painting, and seeking learning.

METHODICAL APPROACHES TO ABSTRACT PAINTING: INSIGHTS FROM ABHIJIT PATHAK

This research emphasises the manner in which Abhijit Pathak, an Indian artist, imbues his abstract paintings with energy through careful and precise techniques, capturing the profound essence of his thoughts. By analysing Pathak's creative process, the study endeavours to identify the strategies and methods he employs in his art. Through interviews with Pathak, this paper reveals his thought process and approach to painting, thereby providing invaluable insights into his art. He deploys a variety of materials and techniques to achieve the desired effect in his paintings, while his approach is marked by discipline and focus. This research illuminates the intricate interplay between cognitive processes, techniques, and outcomes in abstract painting, as observed through Pathak's artistic process. The findings affirm the value of Pathak's systematic approach as inspiration and guidance for other artists, empowering them to develop their unique visual language. His work exemplifies the importance of planning, preparation, and comprehensive knowledge of abstract painting methods and materials. By exploring Pathak's methodology, this paper aims to advance knowledge of abstract painting as a multifaceted and nuanced art form.

Chromosome Rearrangement in Elymus dahuricus Revealed by ND-FISH and Oligo-FISH Painting.

As a perennial herb in Triticeae, Elymus dahuricus is widely distributed in Qinghai-Tibetan Plateau and Central Asia. It has been used as high-quality fodders for improving degraded grassland. The genomic constitution of E. dahuricus (2n = 6x = 42) has been revealed as StStHHYY by cytological approaches. However, the universal karyotyping nomenclature system of E. dahuricus is not fully established by traditional fluorescent in situ hybridization (FISH) and genomic in situ hybridization (GISH). In this study, the non-denaturing fluorescent in situ hybridization (ND-FISH) using 14 tandem-repeat oligos could effectively distinguish the entire E. dahuricus chromosomes pairs, while Oligo-FISH painting by bulked oligo pools based on wheat-barley collinear regions combined with GISH analysis, is able to precisely determine the linkage group and sub-genomes of the individual E. dahuricus chromosomes. We subsequently established the 42-chromosome karyotype of E. dahuricus with distinctive chromosomal FISH signals, and characterized a new type of intergenomic rearrangement between 2H and 5Y. Furthermore, the comparative chromosomal localization of the centromeric tandem repeats and immunostaining by anti-CENH3 between cultivated barley (Hordeum vulgare L.) and E. dahuricus suggests that centromere-associated sequences in H subgenomes were continuously changing during the process of polyploidization. The precise karyotyping system based on ND-FISH and Oligo-FISH painting methods will be efficient for describing chromosomal rearrangements and evolutionary networks for polyploid Elymus and their related species.

3Y-TZP electrostatic painting to increase bond strength to dentin and dental prostheses

Although the clinical method used to improve the adhesion of zirconia prostheses to other materials is sandblasting or acid etching surface, the failure rate of the bond is high. The present work aims to propose an innovative method of zirconia surface painting with an electrostatic technique using epoxy powder paint with antibacterial and antifungal properties to improve the adhesion to dentin. The zirconia samples were divided into 4 groups: without surface painting (GC), painted without surface treatment (G1), hydrofluoric acid etching before painting (G2), and blasted with alumina before painting (G3). The samples were characterized by X-ray diffraction, scanning electron microscopy, Vickers hardness, 3D roughness, and cytotoxicity. Shear bond strength (SBS) tests were used to measure the zirconia bonding to synthetic dentin (NG-10 polymer). The opacity of painted zirconia was evaluated using a spectrophotometer with contrast ratio as a translucency parameter. The results showed the sintered zirconia had high densification, and submicrometric tetragonal (t-ZrO2) and cubic (c-ZrO2) grains. The bonding shear strength of zirconia without surface painting and surface treatment (3.51 MPa) was the lowest. The highest bonding strength was painted zirconia without surface treatment (15.51 MPa). The zirconia etched with HF had a lower shear strength (5.75 MPa) than the zirconia blasted with alumina (7.76 MPa). As the painting coating thickness increased, the opacity increased. The cytotoxicity tests showed that the coated zirconia is biocompatible. The zirconia painting with epoxy powder paint methodology facilitates the manufacture of dental prostheses and increases the shear bonding strength to dentin.

Study And Appreciation Of Claude Monet’s Artistic Creation And Life Experience

Claude Monet an outstanding Impressionist painter in the 19th century, is one of the founders of Impressionist painting, known as the "father of Impressionism". His representative works include Impression of Sunrise, Cathedral of Rouen, Haystack, and Water Lily. Many artists and scholars in the study of Monet's works, summed up the artist Monet can be famous for the reason: thanks to his unique insight and innovation in painting creation. Every seemingly insignificant change over time will eventually add up and change things qualitatively. This paper makes a correlation analysis between Monet's painting style and his life experience to explore the influence of the painter's life experience on the painting methods adopted at that time, to study and appreciate his representative works which have achieved periodic success. When people not only stop to appreciate the color surface of the work, but also understand the story behind the creation of art, this will more vividly and truly restore the character image of a writer, and further explore the connotation, historical status, and influence on the development history of painting. At the same time, it is beneficial to broaden the richness of the history of art painting and is also of great benefit to the field of art education and academic research.

关于云南现代重彩画之源流的研究

This paper analyzes and summarizes the reasons for the formation of Yunnan modern heavy-color painting, including its social background, regional environment, and ethnic traditions. Among them, traditional national culture plays an important role in Yunnan modern heavy-color painting, providing a profound cultural background for the development of this art form. Additionally, this paper analyzes the current development status of Yunnan modern heavy-color painting and identifies some existing issues. Addressing these problems, the paper summarizes the development experience of Yunnan modern heavy-color painting and discusses its future development path. Yunnan modern heavy-color painting is an innovative and unique art form, but it also faces new challenges in its continuous development. To address these challenges, we need to adopt reasonable strategies to further improve the theoretical system and technical methods of Yunnan modern heavy-color painting and promote its innovation and development. In this process, Yunnan modern heavy-color painting needs to fully leverage the advantages of regional culture, humanistic tradition, and social value.

Miniaturization and Model-Integration of the Optical Measurement System for Temperature-Sensitive Paint Investigations.

The temperature-sensitive paint (TSP) method, an optical measurement technique, is used for qualitative skin friction visualizations in a wide variety of aerodynamic applications. One such application is the visualization of the laminar-turbulent boundary-layer transition. Optical access to the surface of interest is mandatory for the measurement system, which consists of scientific cameras and LEDs. But the optical access to the area of interest is often impeded by the available windows of the wind tunnel and the wind tunnel model itself, reducing the field of view and the spatial resolution. In some cases, it is of interest to increase the flexibility of the installation of the optical measurement system by reducing its physical dimensions and placing the installation inside the plenum. The DLR Swept flat PlatE Cross-flow TRAnsition (SPECTRA-A) configuration was selected to investigate the influence of two-dimensional steps on the cross-flow-induced boundary layer transition by means of TSP, as part of the EU project Clean Sky 2. The SPECTRA-A configuration consists of two main elements: a flat plate and a displacement body mounted within a very close distance of each other, creating a narrow gap between the two elements. The surface of interest is the area on the flat plate facing the displacement body. The narrow gap limits the utilization of an external camera setup due to poor optical access. A new optical setup consisting of four miniature CMOS machine-vision cameras and five miniature high-power LEDs was integrated into the displacement body. The characteristics of the camera system were analyzed in laboratory tests, establishing that the miniature CMOS machine-vision cameras are suitable for qualitative TSP skin friction visualizations. This was confirmed by successfully measuring the laminar-turbulent boundary-layer transition on the SPECTRA-A configuration. The integrated TSP system is capable of resolving even small variations of the transition location caused by changing the amplitude of the stationary cross-flow instability. The quality of the TSP visualization with the integrated optical system allows for the measurement of the transition location and the wavelength of the stationary cross-flow instability. Overall, a cost-effective TSP visualization system with small space requirements was developed and tested for future applications in wind tunnel models, model support, or side walls of wind tunnels.

Interpretation of x‐ray spectral data using self‐organising maps and hierarchical clustering: A study of Vilhelm Hammershøi's use of painting materials

AbstractThe goal of the Vilhelm Hammershøi Digital Archive project of the National Gallery of Denmark is to understand the Danish painter Vilhelm Hammershøi's painting methods by compiling a comprehensive amount of data on his use of materials and working methods through visual and technical examination of a large number of his paintings, and to make this information available to researchers and the public in an open access digital resource. A clear understanding of the full suite of pigments across the paintings requires determination of which materials comprise the palettes of the ground and paint layers. Scanning electron microscopy/energy‐dispersive x‐ray spectroscopy and macro x‐ray fluorescence spectroscopy were selected as the key analytical techniques due to their ability to yield chemical information at the elemental level. This article presents a method that combines unsupervised machine learning and cluster analysis techniques, to automatically reduce the large x‐ray spectral data to sets of distinct clusters that share similar spectra, making it possible to identify materials more precisely. The proposed method allowed the grouping of materials by chemical composition, which enabled an optimal understanding of the pigments used in the ground layers sampled from a large number of paintings as well as in the paint layer examined at the surface of one selected painting. The method performed well when compared with other well‐established data mining techniques, and it helped reduce the time necessary for the interpretation of the analytical results significantly. Through this approach, a basis for a more nuanced view of Hammershøi's artistic idea and technical development will be generated.

The Application and Research of Illustration Art in Brand Image

Illustration, as a more direct image expression than text communication, has spread from ancient times to the present, broadly speaking, from the stone age murals to the patterns on bronze heavy objects, and then to the New Year pictures posted by every household in ancient times. It is the best way to explain the information by image processing. However, in modern business, the application of illustrations developed and expanded with the changes of newspapers and books in the early 19th century. With the variety of illustrations becoming more and more abundant, and the differences in painting methods and painters' values and artistic concepts, there is the art of illustration. The most important point of illustration art is that it can visually express the information conveyed in the text, and it is more direct and vivid. Since the evolution of illustration, the visual emotional design and content communication in brand image are becoming more and more irreplaceable. This paper will focus on the role and significance of illustration art in brand image, and give examples with my graduation design and "Free" hot pot series of illustrations to provide a certain theoretical basis for the study of art in brand image.

More than a Man, Less than a Painter: David Smith in the Popular Press, 1938–1966

Media coverage was vital in establishing the popular reputation of the Abstract Expressionists. Reporting regularly relied on photographic portraits to present these artists as modernist innovators who were an extension of (or even a replacement for) the work of art. Jackson Pollock came to epitomize the Abstract Expressionist artist, with “action” photographs capturing his radical painting method. Pollock’s contemporary, American sculptor David Smith, similarly transformed his medium—in his case by embracing industrial methods to make three-dimensional objects. However, given the constraints inherent in the process of welding he employed, how could Smith’s image be reconstituted as a celebration of artistic individuality so crucial to modernism? The very method Smith embraced to push the boundaries of art kept him from representing the genius creator who channeled the forces of nature to produce culture. By tracing photographs documenting his career published in local and regional newspapers, popular magazines from Popular Science to Life, and mass art magazines from Magazine of Art to Arts, this paper demonstrates that images of Smith at work as an anonymous industrial worker enveloped in protective gear were regularly balanced with images of contemplation—the traditional image of the artist as mediating intelligence. Yet, over the years of his career, the problem of representing Smith was addressed somewhat differently. Early on, there was a tendency to show Smith applying his novel art-making techniques to the production of more traditional objects. During World War II, when Smith was employed as a commercial welder, Smith the artist legitimized reporting on Smith the worker. Finally, in the post-war world—as Smith benefited from the burst of publicity surrounding the triumph of Abstract Expressionism—his rigorous manipulation of metal was celebrated as masculine display, effectively shifting attention away from common industrial labor to heroic individual struggle.

Imaging Techniques of Tomatoes (Solanum Lycopersicum L.) Grown with Different Organic and Conventional Fertilizer Applications

In this study, which was carried out in field conditions in Van in 2019 and 2020, different image generation methods (biocrystallization method, and circular and rising picture chromatography methods) were used to determine the difference between various organic and conventional fertilizer applications. 3% frozen tomatoes and 16% CuCl2.2H2O were applied in the biocrystallization method, 80% frozen tomatoes and 1% silver nitrate solution were used in the circular chromatography method, and 100% frozen tomatoes and 0.5% silver nitrate and 0.5% iron sulfate solution were employed in the rising picture method. In light of the visual findings obtained at the end of the study, it has been determined that there are some differences between organic and conventional fertilizer applications. As the alteration between organic and conventional products; the center number difference in the copper crystallization method; the smoothness of the rings formed in the circular chromatogram and the vividness of the colors; in the rising painting method, it clearly reveals the transitions between colors and the difference in light and dark tones that occur in colors.