This paper proposes a cluster-to-cluster image color transform algorithm. Recently, Suntory Flowers announced the development of world's first blue rose “APPLAUSE”. Since roses lack the blue pigment, it was long believed to be impossible. The key to success lies in the introduction of blue gene from pansy into rose. In the previous paper, PCA matching model was successfully applied to a seasonal color change in flowers, though it's not real but virtual. However, the tonal color transitions between the different color hues such as red rose and blue pansy were not so smooth but unnatural because of spatially independent color blending. In addition, the clear separation of blue or purple petal colors from greenish backgrounds is not always easy too. The paper improves the color transform algorithm in the two points, firstly, the clear color separation by introducing a “complex log” color space and secondly, the smoothed tonal color transition by introducing a “time-variant” matrix for PCA matching. The proposed algorithm is applied to ROI (Region Of Interest) image color transform, for example, a blue rose creation from red rose by continuous color stealing of pansy blue.