A method of determining color composition of an image includes calculating an intensity value and a saturation value for each pixel of the image, comparing the calculated intensity and saturation values for each pixel with first and second predetermined threshold values, respectively, and labeling pixels with calculated intensity values above the first predetermined threshold value and calculated saturation values above the second predetermined threshold value as color pixels. Next, a mask is applied to the image and the number of color pixels selected by the mask is counted. If the number of color pixels selected by the mask is greater than or equal to a predetermined density value, the image is determined to be a color image.