Rice husk is a form of agricultural biomass that provides an abundant silicon dioxides source. This study use rice husk ash as a material to prepare silica. Silica powder has been synthesized by the refluxing of rice husk ash with HCl 1,2 and 3 M at different time (60 and 120 min.) and subsequently adjusting the pH using 1 M. NaOH. The silicon dioxide extraction yield reached 85% and was effect by concentration of HCl solution and reaction time. The structure of the obtained silica powder were characterized by X-Ray Fluorescence (XRF), X-Ray diffraction (XRD), CIE L*a*b* (Visible spectrophotometer) and Scanning Electron Microscope (SEM). The highest purity of silica sample were 98.7% SiO2, CIE L*a*b* = 94.79 +0.48 +1.24, ∆E ≈ 3.28 (white power) and 2Ɵ = 22o (silica). Particle had a uniform size less than 3 μm. The objective of the next study will applied synthesized silica that enhances the print quality of the printing substrates.

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To enhance printing qualities, this study used refluxed silica (SiO2) from rice husk by hydrochloric acid (HCl) at different molarities and reaction times as coating agent for printed paper. Characterization of the refluxed silica from 2M HCl 120 min elucidated the purity of 98.7% and amorphous structure. Particle size of the silica exhibited uniform size of 3 μm and the color measurement (CIE L*a*b*) indicated 94.79+0.48+1.24, whiteness and color difference (E) were 84.85, 3.28, respectively. The coating agent was prepared by water-based varnish of acrylic resin mixed with the synthesized silica at different proportions: 0.0, 0.5, 1.0, and 1.5 (%wt), and later was applied on 170 g/m2-white kraft papers. The results showed that the water-based coating varnish with silica exhibited an increase of viscosity as increasing the amount of the silica. Printing qualities indicated that the vanished printed paper with 1.0% silica elucidated the highest details in shadow tone and text (font) sharpness. The color gamut yielded a wider scope than the printed papers which were varnished with the silica at 0.0%, 0.5% and 1.5%. Nonetheless, the color density showed insignificant difference to 1.5% silica varnished paper.

The paper aims to analyst metal sheet printed quality based on ISO12647-2 and color gamut mapping of metal sheet digital proof. ECI2002CMYK test chart was printed on white color coating-metal sheet in 3-density levels with -.1 density differences and the printed quality then was analyzed in various factors. A density level that achieved ISO12647-2 standard quality was selected as the base line for ICC profile for color gamut mapping. Based on this color gamut mapping, the metal sheet digital proof was produced by ink-jet printer through Color Management program. The result showed that metal sheet digital proof appropriate for metal sheet printing simulation.

Rice husk is a form of agricultural biomass that provides an abundant silicon dioxides source. This study used rice husk ash as a material to prepare paper coating. Silica powder has been synthesized by the refluxing of rice husk ash with HCl 1,2 and 3 M at different time (60 and 120 min.) The silicon dioxide extraction yield reached 85% and was effect by concentration of HCl solution and reaction time. The structure of the obtained silica powder were characterized by X-Ray Fluorescence (XRF), Particle size distribution (PSD), X-Ray diffraction (XRD), CIE L*a*b* (Visible spectrophotometer) and Scanning Electron Microscope (SEM). The highest purity of silica sample were 98.7% SiO2, CIE L*a*b* = 94.79 +0.48 +1.24, ∆E ≈ 3.28 (white powder) and 2Ɵ = 22o (silica). Particle had a uniform size less than 3 μm. The paper coating was made from acrylic resin mixed with synthesized silica that refluxing by HCl 2 M 120 min at different ratio (2%, 4% and 6%) and paper coated with a gravure printing machine. The qualities of paper coating were analyzed from viscosity, Transparency (Density) and color gamut of inkjet printing. The paper coating that mixed synthesized silica from rice husk 4% was highest qualities because have viscosity 358 ± 24.99ctp., Density = 0.19, and widely color gamut.