White core thickness effect on 3D-printed color reproduction

Abstract 3D printing is an ever-expanding set of techniques with different materials and applications. Of these applications, color 3D printing has proven to be essential in various fields. Some color 3D printing techniques use colored inks, and the characteristics of these inks, especially translucency and scattering, are vital in color reproduction using 3D printing. 3D-printed color models usually contain two parts: a colored exterior and a hidden white core. Ink translucency is known to affect the output color, but the influence of translucency and scattering from the white core is yet to be studied. Studying the effect of the white core will allow for more accurate color reproduction using translucent ink. In this paper, we investigate the effect of white core thickness on reproduced colors using translucent-colored inks. We quantify and illustrate the change in color via color measurements using a hand-held spectrophotometer and a hyper-spectral camera. CIEDE2000 color difference between the samples varying in white core thickness is calculated, and the visual color change is studied via color gamut comparison. It is observed that, up until a certain thickness, reproduced color, when using translucent inks, varies with the thickness of the white core, even when the colored layers of the samples are intact. This, in turn, means that for optimal color reproduction using translucent ink, the sample size, i.e., the white core thickness, is a variable that should be accounted for in the design process, especially for models with a thickness less than 2 mm.