Chinese color ink painting is a traditional art form, a non-photorealistic rendering, that is over three thousand years old. Simulating the behavior of Chinese ink is challenging. Various artistic effects of color ink diffusion are analyzed, and a scheme presents how they can be simulated automatically for their computer-generated simulation. The proposed method simulates various tonal expressions on different papers, by employing a Kubelka-Munk model to simulate optical effects. Elucidation of the effect of mixing simulated strokes with different brushes is a significant contribution of the proposed method. Finally, results of this study demonstrate the effectiveness of an interactive painting system. Also, results are compared with genuine ink paintings.