This paper presents an innovative pre-dithering or prehalftoning approach of sampling CMY color space using nonlinear sampling of RGB space, under physiological limitations of human color vision. The certified sound color vision human eye color intensity thresholds have been computed in terms of Just Noticeable Differences (JNDs) in each basic color and then used for sampling the color images to be printed. From our findings of color image sampling work, we propose that the existing 22 level quantized ink injection system is inadequate to represent color images with minimum loss of visual information. So we propose an injection system with 24, 26 and 28 levels in Cyan, Magenta and Yellow respectively. The proposed system minimizes the utilization of color inks without affecting visual quality of printed color images on white background. The proposed scheme is effective for printing the dark colors, on the other hand it generates false contours while printing the light colors, as already discussed in published literature. Experimentation has been carried out to estimate the ‘Threshold of Lightness’ of colors in RGB space. Using the decided threshold of lightness, if the proposed scheme is applied only to dark colors, considerable saving of color ink can be achieved. This technique considerably reduces the consumption of expensive color inks for printing color images on white background and enhances the cartridge life, reducing the cost of inkjet printing.