Fig. 4

Repeatability, resolution, colour intensity and retaining time of water-jet prints. a Schematic illustrations of a printing-erasing cycle of WJRP printed with water-jet printer, scale bar = 1 cm. b Photographs of patterns printed on WJRP after 10 consecutive writing-erasing cycles (scale bar = 1 cm). c L*, a*, b* measured by spectrodensitometer and photographs of water-jet prints and ink-jet prints, respectively. d Microscopic images of WJRP before and after addition of water, scale bar = 200 µm. e Photographs of WJRP maintaining in ambient air after printing as time passed by, scale bar = 5 mm. f WJRP based on PET substrate before and after printed with water, scale bar = 2 cm