Abstract:

Objective Referring to the issue of gamut color spaces for structural coloring caused by the restricted primary color configuration and selection of warp and weft for digital jacquard structure, jacquard structure with bidirectional multi-primary color was proposed under layered-combination design mode, the way how three factors namely weave repeat R, the quantity of face weft group(s) N and the transition speed M determine the quantity of warp and weft configuration, face and back layer relationship, coloring compound weave-databases and representative weaves and compound weaves for coloring of jacquard structure basic and derived model were revealed, providing theoretical reference to the construction of jacquard structure model with a finite group of primary color threads and the expansion of its structural gamut color spaces.

Method First, the construction of jacquard structure model with full gamut color spaces based on bidirectional multi-primary color referred to the structural characteristic of double-layer structure, with only face warp and face weft(s) used for coloring. Besides, the basic model with double warps and quadruple wefts and the derived model with double warps and sextuple wefts were established, 4 chromatic colors as well as 2 achromatic colors, namely red, yellow, green, blue, black, and white, were applied to the configuration of thread color, in this case, 4 groups of chromatic threads configurated weft-wised only, 2 groups of achromatic threads were arranged warp-wisely and bi-directionally, with warp threads configurated with 1∶1 ratio, while weft threads allocated under 1∶1∶1∶1 and 1∶1∶1∶1∶1∶1 ratio respectively. What's more, the quantity of coloring compound weave-databases and the quantity of representative weaves and compound weaves for coloring of jacquard structure basic and derived model were calculated and analyzed. Last but not least, the applicability of the two structure models were verified through the comparison of fabric simulation.

Results Jacquard structure model with full gamut color spaces based on bidirectional multi-primary color were illustrated, including jacquard structure basic model with double warps and quadruple wefts and jacquard structure derived model with double warps and sextuple wefts. According to the arrangement sequence of primary color threads, the warp and weft configurations were 48 and 1 440 correspondingly, based on the assignment of the quantity of face weft group(s) N , the face layer and back layer relationships were 28 and 124 respectively without stitching. To stabilize structural coloring characteristics, it is essential to avoid the juxtaposed non-backed effect generated by adjacent face wefts inserted into the same shed when full gamut shaded weaves are combined in succession to form compound weaves for coloring with the quantity of face weft group(s) N equaling or exceeding 2, then the quantity of valid coloring compound weave-databases and the quantity of representative weaves and compound weaves for coloring were obtained according to weave repeat R and the quantity of face weft group(s) N, further, the maximum quantity for total weaves and compound weaves for coloring were 3 605 139 and 84 392 722 413 respectively with 40-threads satin weave and 153 levels of gamut weaves applied for the two structure models, and the characteristics of 6 structural coloring points on fabric simulation revealed that the jacquard structure model proposed is able to adjust chromatic, purity and brightness to enlarge the gamut color spaces of structural coloring.

Conclusion The results demonstrated that achromatic threads configurated codirectionally and bidirectionally conduct to the brightness adjustment of structural coloring in jacquard structure model with bidirectional multi-primary color, besides, with chromatic threads configurated codirectionally and interlaced with achromatic threads according to gamut weaves, the quantity of structural color reaches to the level of {10}^6 and {10}^{11} theoretically for two structure models respectively. Thus, this study contributes to the development and intelligent design research of digital jacquard fabric with full gamut color spaces.

Key words: fabric design, layered-combination design mode, digital jacquard, bidirectional multi-primary color, fabric structure, structural coloring, color scheme