The estimation of illuminant color present in an image is becoming an increasingly important approach in detecting image forensics. The tool presented in this paper can be used to reference the estimations of illuminant color present in a scene of single light sources. Comparisons of images to a reference image database were carried out by analyzing the scale factors produced from the gray world assumption. Using this method, a reference image from the database is chosen as the image of best match which is then used to determine the illuminant color of the image in question. Experimental results show that the deviation of determining the image of best match from the database is affirmative. © 2011 IEEE.