ABSTRACT DING, YI. Color Gamut Comparison Methodology and Evaluation for Textile Ink Jet Printing. (Under the direction of Dr. Harold S. Freeman and Dr. Lisa Parrillo-Chapman.) There is growing interest in making significant portions of the domestic outdoor furniture soft goods production competitive with overseas production as this seasonal, bulky product could be produced more effectively closer to the market. It is anticipated that domestic production can be increased by implementing new technologies in fabric printing operations to enable a) the cost-effective domestic production required for success in servicing the retail sector; b) new product innovations not feasible using current production technologies in this category, and c) a flexible and responsive supply chain capable of quick response to customer market trends. The development of high-speed digital printers, capable of printing 70 m/min, has made this process competitive with rotary screen printing in terms of speed and cost, while offering a competitive advantage when printing shorter runs or multiple colorways. Thus, digitally printed fabrics for outdoor furnishings would offer a game changing strategy for the domestic textile complex. With this in mind, the development of cost-effective digitally printed outdoor fabrics with high UV stability that matches an end user’s color gamut and are readily available and responsive to demand activated point of sale is a logical undertaking. This research sought to develop an understanding of currently used ink jet printing colorants and color management strategy for the outdoor market. The author studied how colors are digitally mixed and color is controlled and matched. The Delphi method was used to investigate current color gamut analysis methods, a critical component of color management systems (CMS). Ink jet printing experts were interviewed, to understand how they manage color and their process for analyzing and comparing color gamuts. A significant result of this study was the development of a four-stage process model for color gamut analysis, color management and print quality evaluation for textile ink jet printing. This study also uncovered an industry initiative toward the improvement of color management systems (CMS) for more accurate color matching, a need to stabilize variables in the manufacturing process, and a need to create standards for related tests and evaluations. The study also revealed new CMS software and technologies developed for ink formulation and pre/post- treatment methods to facilitate high quality production in textile ink jet printing. To test and validate the process model, two experimental studies were conducted. The first study compared and analyzed the color gamut of pre-treated versus un-treated polyester and cotton substrates using a six-color pigment set. The second study compared and analyzed the color gamut and print quality of two different colorant sets, a seven-color disperse set and an eight-color pigment set. The process model was found to be effective for evaluating the two experimental studies. Results of these studies showed that 1) commercially available fabric pre-treatments significantly enhance color gamut for pigment-based ink-jet inks, 2) disperse dye based inks provide a larger color gamut and better crock fastness than pigment- based inks, and 3) pigment inks afford better lightfastness than disperse dye based inks. To assist on-going efforts to enhance the lightfastness of colorants in disperse-based inks for textile ink jet printing, a series of analytical methods were used to characterize the molecular and excited state properties of disperse dyes for modern day ink-jet inks. Results showed that lightfastness was improved by using certain dye mixtures and by eliminating singlet oxygen formation and excited state lifetimes. © Copyright 2016 Yi Ding All Rights Reserved Color Gamut Comparison Methodology and Evaluation for Textile Ink Jet Printing by Yi Ding A dissertation submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy Fiber and Polymer Science Raleigh, North Carolina 2016 APPROVED BY: _______________________________ _______________________________ Dr. Harold S. Freeman Dr. Lisa Parrillo-Chapman Committee Co-chair Committee Co-chair _______________________________ _______________________________ Dr. Renzo Shamey Dr. Ahmed El-Shafei DEDICATION 给我的父亲母亲(To my Dad and Mom). ii BIOGRAPHY Yi Ding grew up in Anqing, China, which is a beautiful city nearby the Yangze River. She finished her first three years of undergraduate school at Donghua University, Shanghai, majoring in Textile Engineering, and joined the 3+X exchange student program at North Carolina State University in Fall, 2011. After completing her Master of Science degree in Textile Chemistry in summer, 2013, she decided to pursue a doctoral degree in Fiber and Polymer Science. Her research involved various aspects of textile ink jet printing technology and was supported by the Walmart Innovation Fund. iii ACKNOWLEDGMENTS The author wishes to acknowledge the Walmart Innovation Fund for supporting her dissertation research, and the time and expertise contributed to this body of research by members of academia, industry, and research institutes in the field of textile ink jet printing. Similarly, the interview and experiment study participants provided invaluable, thoughtful observations and opinions about the ink-jet printing design process, and were generous in sharing their experiences in this field. The author is grateful to all the professors on her advisory committee for their support. Dr. Harold S. Freeman provided guidance on the dye chemistry study and served as a role model of an educator, teacher, and chemist. Dr. Lisa Parrillo-Chapman provided important oversight of the textile ink jet printing and Delphi method study and helped her work through many technical issues. Dr. Renzo Shamey and Dr. Ahmed El-Shafei gave important knowledge to help me address challenges pertaining to color science and photochemistry. The author also extends her appreciation to all the professors and graduate students on the Walmart project team, Dr. Trevor J. Little, Dr. Andre West and Professor Nancy Powell, for their generously support throughout her involvement in this interdisciplinary study. They freely shared knowledge with each other and gave her many helpful suggestions. Dr. Jihye Lim assisted her with completing numerous fastness tests. She would also like to offer her gratitude and appreciation to all the members of Dr. Freeman’s research group, especially Dr. Malgorzata Szymczyk and Dr. Nahid Mehraban who assisted her with completing the dye characterization and analysis study. It has been five iv years since she joined this family. Their strong encouragement and mutual respect helped her have good success as an international student. Finally, she would like to appreciate Mr. Jeffery Krause, Ms. Judy Elson and Mr. Tri Vu and all the other staff in College of Textiles and chemistry department, who helped her to solve many technical issues over the past three years. v TABLE OF CONTENTS List of Tables...………………………………………………………………………………xii List of Figures.………………………………………………………………………………xvi Introduction ....................................................................................................................... 1 1.1 Research Objective ................................................................................................... 3 1.2 Relevance of Research .............................................................................................. 3 Literature Review.............................................................................................................. 5 2.1 Background ............................................................................................................... 5 2.2 Textile ink jet printing technology ............................................................................ 8 2.2.1 Printer/Printhead ................................................................................................... 9 2.2.2 Drop formation and impaction ............................................................................ 12 2.2.3 Drop impact on the substrate .............................................................................. 13 2.2.4 Textile handling .................................................................................................. 14 2.3 Digital color management system ........................................................................... 15 2.3.1 Color perception.................................................................................................. 15 2.3.2 Color mixing methods......................................................................................... 17 2.3.3 Digital color spaces ............................................................................................. 19 2.3.4 Color Management System (CMS) ..................................................................... 23 2.3.4.1 Color calibration, characterization, and profile creation ............................ 26 2.3.4.2 Color reproduction ...................................................................................... 27 2.3.4.3 Rendering intent .......................................................................................... 27 2.3.4.4 Color gamut mapping ................................................................................