Color has historically seen limited use in metallography, mainly due to the cost of film and prints and the difficulty and cost of reproducing images in publications. With the growth of digital imaging, however, capturing color images is much simpler and cheaper.
Color does have many advantages over black and white. First, the human eye is sensitive to only about 40 shades of gray from white to black, but it is sensitive to a vast number of colors. Tint etchants reveal features in the microstructure that often cannot be revealed using standard black-and-white etchants. Color etchants are sensitive to crystallographic orientation and can reveal if the grains have a random or a preferred crystallographic texture. They are also very sensitive to variations in composition and residual deformation. Further, color etchants are usually selective to certain phases, and this is valuable in quantitative microscopy.