Contrast enhancement is one of the most important issues in medical image processing. Many Contrast Enhancement techniques have been proposed so far. Comparison of image enhancement techniques is considerably significant in deciding which algorithm to use for enhancement and image assessment. In this paper, a comparative study of indirect image contrast enhancement techniques is attempted on the low contrast mammographic images. The performance measures namely effective measure of enhancement (EME), peak signal to noise ratio (PSNR) are used to investigate the performance of the enhancement techniques.