Study of color reproduction in pigment digital printing

Abstract

In pigment ink digital printing, the color difference between the original and the printed product can be visible due to the varied color gamut of devices and the impact of fabric characteristics on the color-presenting effect. To improve the color reproduction accuracy of digital printing, two methods, the full-process optimized (FPO) method and the neural network aided original adjustment (NNAOA) method, were proposed to reduce printing color difference during the color-transferring process. The FPO method, based on accounting for the fabric type and the characteristics of the printing machine, was proposed by optimizing the printing parameter settings in the color management process. Here, the optimal single-channel ink limit was determined and dot gain was compensated using the inverse function correction method, and then the International Color Consortium profile was generated. After using the FPO method, the color difference between the printed sample and the original was reduced from 20.8 to 5.254 compared with performing the original color management. To reduce the reliance on personal experience in color adjustment, the NNAOA method was proposed and implemented for 20 color patches with the largest color differences in the FPO method, allowing the color of the originals to be adjusted with the establishment of the general regression neural network model. This method predicted the input CMYK values of the original using measured L*a*b* values for the printed sample. The results showed that the color difference of the 20 color patches was reduced from 8.54 to 6.60. Consequently, both methods offered distinguishable improvements in the color reproduction effect.

Design and Fabrication of Thermochromic Jacquard Woven Fabrics

“…The microencapsulated thermochromic powders in the yarn cause the color change of the yarn reversibly when the temperature changes. The critical temperature [6] to initiate the color change of the yarn is 31 ℃. The warp yarn is a 16.7 tex polyester yarn.…”

“…Yu et al [5] employed plastic optical fiber as weft yarn in jacquard weaving process to produce luminous jacquard fabric with tunable pattern colors. Among these functional textiles, reversible color-changing fabrics can effectively demonstrate the aesthetical value of jacquard woven fabrics with beautiful patterns when they are potentially used as recreational clothing and anti-counterfeit signs [6,7], etc.…”

“…Based on the color-changing mechanisms of the fibers, they can be divided into several types such as stress-induced color-changing fibers, photochromic fibers, thermochromic fibers and electrochromic fibers, etc. [6] Generally, stress-induced discoloration requires external forces to cause the deformation, photo-induced discoloration requires the exposure of the fabric to UV light, whereas electroinduced discoloration requires the application of an electric field [6,8]. These conditions that trigger discoloration often cause fabric deformation or aging, which reduces the service life of the fabrics.…”

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“…Based on the color-changing mechanisms of the fibers, they can be divided into several types such as stress-induced color-changing fibers, photochromic fibers, thermochromic fibers and electrochromic fibers, etc. [6] Generally, stress-induced discoloration requires external forces to cause the deformation, photo-induced discoloration requires the exposure of the fabric to UV light, whereas electroinduced discoloration requires the application of an electric field [6,8]. These conditions that trigger discoloration often cause fabric deformation or aging, which reduces the service life of the fabrics.…”