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This study aims to examine the colour changes affecting inkjet prints after the recycling of papers.

For recycling, papers prepared with the INGEDE 11p standard are recycled four times. Pulping, storage, flotation, beating and bleaching processes are applied for each recycling, respectively. Inkjet prints are made on the obtained test papers, and colour measurements are made using an X-Rite eXact spectrophotometer according to the ISO 13655:2017 standard. These processes are applied again to the papers which are recycled four times, and the results are analyzed. In addition, the values of ΔE₀₀ ′, ΔL′, ΔH ′ and ΔC′ are calculated according to ISO 11664-6:2014 standard by making some calculations according to obtained the L′a′b′ values.

It is determined that the ΔE₀₀ value increases after each recycling in cyan magenta and yellow colour, whereas it decreases in black. The highest ΔE₀₀ value is calculated after the fourth recycling stage is yellow with a value of 8.33. The lowest ΔE₀₀ value detected is black with a value of 0.76 after the fourth recycling stage. This paper observes that the colour with the most variation in hue angle among recycling repetitions is black and the colour with the highest hue angle value is yellow. It is seen that repeating recycling causes increase in the chromatic values of the prints.

After the fourth recycling stage, colour changes have reached an important point and can cause important printing problems. In this case, the customer’s approval must be obtained to continue printing. This case is valid for ΔE₀₀ values. Colour differences for print contrast, trapping and print chroma values are either not very important or are positive for quality.

The purpose of this paper is to optimize the key parameters (mesh count, paper type and ink type) in screen printing, which are affecting the printed ink volume. The objective of the optimization was to maximize the color reliability by decreasing the color difference (ΔE value) of the prints while minimizing the ink consumption. Screen printing is still dominating the printing industry to make cost-effective production when high volumes are needed.

The experiment was designed using the Taguchi method, and the samples were prepared with screen-printing by using the standard squeegee angle and pressure. The effect of mesh count, ink type and paper type on ink consumption was evaluated with using analysis of variances and main effects plots of S/N ratio and standard deviation.

The factors ink type, paper type and mesh count were found significant for ink consumption due to their Probability (P) values which were lower than 0.05. It was determined that the mesh count was the most critical variable with the analysis of variance. The analysis showed that the selection of an optimum mesh count was the key to controlling the amount of the deposited ink. Although mesh counts were inversely proportional with the ink consumptions, they did not affect the color differences as expected.

The optimization of process parameters, that are most effective on the print quality, is necessary to minimize the ink usage and lower the costs and environmental impact without exceeding the desired ΔE value limits.

The most important appearance attribute of a product is undoubtedly colour; however, the overall appearance of the product involves other attributes, including gloss, lustre and translucency. Such factors must be considered in making a judgment involving appearance, whether the judgment is visual or instrumental.

The purpose of this paper is to investigate the ability of the computer vision system (CVS) to evaluate the colour of poultry meat. The advantages of the CVS over traditional methods were also explored.

The research was carried out on m. pectoralis major samples of three animals for each of the following four species: chicken, turkey, duck and goose. The total colour difference (ΔE) and the degree of difference of hue, chroma and lightness between the methods were calculated. In addition, a trained panel of 14 people was used to carry out three different similarity tests analysed using χ² one sample test and one-way ANOVA. The correlation coefficient between CVS and colourimeter measures was evaluated using the Spearman rank correlation test.

The total colour difference (ΔE) between the methods employed was so large that the generated colour(s) could be considered more opposite than similar. The CVS-generated colour chips were more similar to the sample of the meat products visualised on the monitor compared to colourimeter-generated colour chips in all (100 per cent) individual trials performed. The use of the colourimeter for colour evaluation of lighter coloured poultry meat (chicken and turkey) was unrepresentative.

In this study, a CVS was developed to measure the colour of poultry meat as an alternative to conventional colourimeters.

The research has demonstrated that the use of a CVS should be considered a superior alternative to the traditional method for measuring colour of chicken, turkey, duck and goose meat.

The purpose of this publication is to describe the possibility of using a scanner for the evaluation of color variation or color difference of textile fabrics. Initially, the color specification of colored fabrics were measured by spectrophotometers and the actual color differences between colored fabrics were calculated by the δE*ab color difference formula. Then, a scanner was used to take images of the textile fabrics. The obtained images were filtered for noise removal. The RGB values of the obtained images were used for the evaluation of textile fabrics color variation. Several methods were used to evaluate color difference by a scanner. The best prediction was obtained by the neural networks methodwith 1.014 δE*ab. Using this method, the accuracy of prediction for training sets was better than that for the testing sets. The performance of each method depends on the color difference values. so that, for low and high color difference, the best prediction was obtained by neural network, and for median color difference, the best prediction was obtained by the multi linear regression method. The obtained results show that the color variation of textile fabrics can be estimated by using scanner RGB variation.

The health and environmental hazards associated with synthetic dyes have led to a revival of natural dyes that are non-toxic, environmentally benign and coupled with various functions. The study aims to investigate and develop the potentiality of a popular herb called Chromolaena odorata (C. odorata) as a sustainable and stable dyestuff in textiles.

Natural colorant extracted from C. odorata leaves is used to dye the worsted fabric, which is one of the premier end-use of wool in fashion, via the padding method associated with pre-, simultaneous and post-mordanting with chitosan, tannic acid and copper sulfate pentahydrate. The effects of extraction, dyeing and mordanting processes on fabric’s color strength K/S and color difference ΔE_CMC are investigated via International Commission on Illumination’s L*a*b* color space, Fourier transform infrared spectroscopy, scanning electron microscope, color fastness to washing, rubbing, perspiration and light.

The results obtained indicate extraction with ethanol 90% with a solid/liquid ratio of 1:5 within 1 h, and coloration with a liquor ratio of 1:5 (pH 5) within 2 h under padding pressure of 0.3 MPa are the most effective for coloring worsted fabric.

The C. odorata’s application as a highly effective dyestuff possessing good colorimetric effectiveness has expanded this herb's economic potential, contributing partly to economic growth and adding value to wool in global supply chain.

C. odorata dyestuff has prevailed over other natural colorants because of its impressive color fastness against washing, rubbing, perspiration and especially color stability for pH change.

The purpose of this paper, on innovative design of traditional weft-backed woven fabric, is to investigate a design principle and method for full-backed structure with double-faced shading effect to realize two types of double-faced shading effects for traditional weft-backed fabric that are impossible to be realized under plane design mode. In addition, the study on the color rendering law is conducive to the design application, and the effectiveness of the design method has been verified by the design practices.

This paper presents a design method for full-backed structure with two shaded weave databases (SWDs) by selecting two primary weaves (PWs), establishing the corresponding SWDs, selecting the proper compound structures for database of full-backed structure with double-faced shading effect. Color card fabric with 544 specimens is produced and their color values are measured, their color difference and variance are analyzed to evaluate the color rendering characteristics. Finally, double-faced weft-backed fabrics are produced under layered-combination design mode to verify the practicality of full-backed structure with double-faced shading effect.

Weft-backed woven fabrics with “SPDC” (same pattern and different color) and “DPDC” (different pattern and different color) shading effects can be produced using full-backed structure with double-faced shading effect. The color expression is extremely enhanced (136 compound structures on one side for one color weft). In the shading process, two sets of wefts do not affect each other, and stable and ideal color shading effect with high color purity can be expressed according to the analyses on the L* (lightness) values, color purity, color differences (0.47–3.20) and variance (0.25–1.21) of the color card fabric.

Breaking through the structural limitations and achieving the double-faced shading effects that cannot be expressed in plane design mode. The research on two weft-backed fabric with the most basic weft-backed structure provides not only a theoretical base for further study on weft-backed structures, but also some references for structure innovation design of traditional weft-backed woven fabrics.

The purpose of this paper is to improve the dyeing effect of fast-growing fir wood dyed with reactive dyes.

In this study, five factors including temperature, the dosage of dye accelerator, dyeing time, the dosage of fixing agent and fixing time were investigated. Then, the color difference and light resistance of the wood surface after dyeing were used as the evaluation indicators; the best dyeing process under the two indicators was obtained through the range analysis. Finally, the two indicators were considered comprehensively, and the fuzzy comprehensive evaluation method was used to obtain the best dyeing process under the comprehensive indicators.

The results show that when the comprehensive index was used as the evaluation index, the optimal dyeing process for reactive red X-3B dyeing fast-growing fir veneer was that the dyeing temperature was 65°C; the amount of dye accelerator was 25 g L⁻¹; the dyeing time was 2 h; the amount of fixing agent was 15 g L⁻¹; and the fixing time was 35 min.

The technique of wood dyeing is an important method to increase the value of wood products. When using different kinds of dyes or dyeing substrates for wood dyeing, the dyeing process is different. This study determined the best process for reactive dye dyeing of fast-growing fir veneer and provided a solution for improving the value of fast-growing fir wood.

In this article, a simple system will be presented to measure reflectance of metallic surfaces quickly and precisely based on goniospectrophotometric geometry. The paper aims to discuss these issues.

This system works by capturing reflected light from different colored patches by digital camera and with the knowledge of spectral power distribution of light source and defined observer, reflection of each sample can be reproduced. By fixing the light source, the position of the detector would be eliminated to four angles of observation.

This method can achieve acceptable reconstruction accuracy for metallic samples. This approach confirmed repeatability and practicality of the simple imaging acquisition to replace spectral reflectance measurement devices in different viewing angles.

The reflectance of metallic samples has been measured at several angles such as 20°, 45°, 75° and 110° from specular reflection. A simple system was used to measure multi-angle reflectance of metallic surfaces by digital camera. By suggested system can be measured the reflectance without contact and limitation in the shape of surfaces. This method achieved acceptable reconstruction accuracy for metallic samples. This simple imaging acquisition is comparable with goniospectrophotometer for measuring multi-angle reflectance of metallic samples.

Today, Jacquard woven fabric producers are able to digitally control each warp yarn individually, pre-program the variable pick density and speed for each filling yarn, and automatically change a pattern without stopping the weaving process. Jacquard CAD systems dramatically reduce the time to produce fabric from the artwork or target design The process of weave/color selection for each area of the pattern is, however, still highly dependent on the CAD system operator who works from a particular color gamut. Multiple weaving trials are required to get a sample that matches the original artwork since the process requires the designer‘s subjective evaluation. The lack of automatic selection of weaves/color matching prompts this research.

This paper addresses the development of a geometric model for predicting the color contribution of each warp and filling yarn on the fabric surface in terms of construction parameters. The combination of geometric modeling and existing color mixing equations enables the prediction of the final color of different areas of a Jacquard pattern. The model was verified experimentally and a close agreement was found between a color mixing equation and the experimental measurements.