Image enhancement is the simplest and most appealing area among all the digital image processing techniques. The main purpose of image enhancement is to increase contrast in a low contrast image. Image enhancement schemes are used for enhancement of images which includes gray scale manipulation, filtering and histogram equalization. Histogram equalization is one of the well known image enhancement technique. Histogram equalization becomes popular technique for contrast enhancement because this method is simple and effective. This paper represents review of some techniques in the area of image enhancement for brightness preservation because brightness preservation is highly demanded in consumer electronics field, when the image is effectively enhanced. Comparative analysis of different enhancement technique is done to illustrate the best possible technique which can be used as image enhancement. This comparison will be done on the basis of subjective and objective parameters. Subjective parameters are visual quality and computation time and object parameters are peak signal to noise (PSNR), Mean squared error (MSE), Normalized absolute error (NAE), Normalized correlation, Error color, Composite peak signal to noise ratio (CPSNR) and Absolute mean brightness error (AMBE).