While emphasizing the intensity or saturation component in order to obtain high-quality color images, keeping the hue component unchanged is important; thus, perceptual color models such as HSI and HSV were used. Hue-Saturation-Intensity (HSI) is a public color model, and many color applications are commonly based on this model. However, the transformation from the HSI model to RGB model after the processing intensity and saturation in the HSI model usually generates the gamut problem, because, the HSI gamut is larger than the RGB gamut. Nevertheless, the common area of RGB gamut and HSI gamut is large to the middle value of the intensity. In this paper, we propose a new color image processing scheme in HSI color model. In the proposed scheme, the positive image processing and the negative image processing are performed in parallel. Since we can realize the negative processing system which is equivalent to the normal (i.e., positive) processing system, the proposed scheme is same degree-of-freedom of the normal processing scheme. In the negative image processing, color images are treated as CMY color space. The common area of CMY gamut and HSI gamut is large from the middle value of the intensity. Therefore, if the intensity value until middle, we choose the positive image processing result as the final result of our scheme. On the other hand, if the intensity value larger than middle value the result of negative image processing result is chosen as the final result. Due to that, we can almost avoid the gamut problem by the proposed scheme.