If you have a TeX or LaTeX document written with color macros and you want to print it in black and white there are two options. On all (good) PostScript devices, printing a color file will print in corresponding gray levels. This is useful to get a rough idea of the colors without using expensive color printing devices. The second option is to replace the call to input `colordvi.tex' with `blackdvi.tex' (and similarly for the `.sty' files). So in the above example, replacing the word `colordvi' with `blackdvi' suffices. `blackdvi.tex' defines the color macros as no-ops, and so will produce normal black/white printing. By this simple mechanism, the user can switch to all black/white printing without having to ferret out the color commands. Also, some device drivers, particularly non-PostScript ones like screen previewers, will simply ignore the color commands and so print in black/white. Hopefully, in the future screen previewers for color displays will be compatible with some form of color support.