The power-law transformation [6],[8] is useful for general purpose contrast manipulation. It has been applied to various applications [7],[11],[12]. For a dark input image, an output image is accomplished by using a power-law transformation with r less than 1(fraction exponent). For an input image having a washed-out appearance, the output image is obtained by using a power-law transformation with r greater than 1. The power-law function can generate a family of possible transformation curves obtained by varying the r parameter. Therefore, it can be applied easily for any type of image for better contrast and highlighting in order to get a meaningful output for any purpose. The power-law transformation is also used in a variety of devices such as computer monitors, printers, and image acquisition devices. The exponent in the power-law equation is referred to as gamma. Therefore, the power-law transformation is also called as gamma correction. To reproduce colors to display on a computer screen accurately, it also the requires knowledge of gamma correction because changing the value of gamma changes not only the brightness but also the R,G,B components in a color image. In this paper, We intend to seek for a suitable set of gamma value for accurately displaying color of indigo-dyed textile images on computer screens.