Because of the light from the back of a subject, a counterlight image has a huge difference of illumination between the light area and the shaded area. In order to enhance the contrast of the counterlight image, Retinex can be used. However, the color distortions occurs when Retinex is applied to a low illumination pixels. We examine the problem of Retinex on the counterlight image, and propose a prepossessing method to apply the Retinex to the counterlight image.