1. A method, comprising: copying each green intensity value in a color digital image into a corresponding pixel location of a grayscale digital image; for each red intensity value in the color digital image: adjusting the red intensity value to match a local dynamic, range of green intensity values; inserting the adjusted red intensity value as the grayscale intensity value of the corresponding pixel location of the grayscale digital image; for each blue intensity value in the color image: adjusting the blue intensity value to match a local dynamic range of green intensity values; inserting the adjusted blue intensity value as the grayscale intensity value of the corresponding pixel location of the grayscale digital image.