A method of sharpening a digital image having image pixels values includes the steps of: determining a D.sub.min value, representing a value corresponding to a minimum possible exposure for a system that produced the digital image; for each pixel value in the digital image providing a gain factor that is dependent on the difference between the pixel value and the D.sub.min value, such that pixel values nearer the D.sub.min value have smaller gain factors; and using the gain factors to sharpen the digital image.