Using the rainbow holographic technique, a color or an achromatic image can be obtained from the superposition of various rainbow holograms on a single plate. Since the color of the reconstructed image depends on the observation angle, the desired image is obtained at a specific viewing position. Using Kogelnik's theory an analysis of the image's color variation under different recording and reconstruction conditions is performed. The analysis helps to find adequate recording parameters to improve the luminance of the final reconstructed image.