The present study aims to evaluate the impact of process factors on the optical characteristics of seashell-added glazes using a 2³ factorial design. Seashells collected from the Black Sea beaches of Samsun, Turkey, were calcined for 1 hour at 700 °C. XRD and XRF analysis were used to perform chemical characterization of seashell powder. Seashell powders were added to commercial transparent glaze compositions dipped onto the surface of sintered ceramic bodies such as white and porcelain mud. The glazed ceramic bodies were sintered for 8 hours at 1000 °C and 1100 °C. The spectrophotometer determined the coloring parameters and gloss values of seashell-added glazes. The effect of utilizing the seashell powder on the color parameters of glazes was investigated using the experiment’s factorial design. The process factors were firing temperature, ceramic body, and seashell powder addition ratio. The study proved that the firing temperature significantly affects the optical properties of glazed samples in a 2³ level factorial design. The substrate and additive ratio are the main factors for gloss value, whereas firing temperature is the main controlling factor for values L*, a*, and b*. By analyzing the impact of the variables and evaluating the color properties of ceramic glazes, the statistical approach of the factorial design was utilized to minimize testing efforts and optimize experimental data.

Keywords: Factorial design, Ceramic, Seashell, Optical properties, Glaze.