The production of stable emulsions for various industrial applications is crucial and at the same time, challenging. Emulsions are commonly categorized into three main types: water-in-oil, oil-in-water, and multiple or complex emulsions. Among these, water-in-oil emulsions hold particularly significant in the context of the printing ink industry. These emulsions commonly employ mineral oil as the oil phase, which poses various environmental concerns. This study focuses on the development of a stable water-in soybean oil emulsion for risograph printing ink using a microfluidic process as a step towards reducing environmental pollution. The control of emulsion particle size was achieved through the microfluidic technique, while stability was enhanced by selecting the appropriate emulsifier and its concentration. Two emulsifiers, PGPR and Span80, were employed at various loading levels of 4, 6, 8, and 12 wt%. The findings indicate that emulsions produced with PGPR emulsifier exhibited greater stability compared to those prepared with Span80. Moreover, an 8 wt% emulsifier loading level resulted in an emulsion with particles smaller than 5 μm and exceptional stability. The influence of injection speed was also investigated, revealing that an injection speed of 70/30 ml/min water/oil yielded a stable emulsion with a narrow particle size distribution. This research sheds light on the factors impacting stability in liquid water-in-oil emulsions and fosters innovation in the development of novel products and applications, particularly within the printing ink industry.