http://members.aol.com/fotodave/dignegs.html
You will find it easier to understand what I said. (You might agree or
disagree with what I said, but it is still easier to know *what* I said with
the illustration).
Note that in the title, I use the word "modeling." That is, admittedly, an
engineering term. Photographic materials and processes are very complicated,
so many times it is very difficult to use just one illustration to explain all
the phenomena. However, modeling means that we use a model to reasonably
explain some particular phenomena that we are observing and studying.
Since it is a model, it cannot be called completely right or wrong. It
explains something well but maybe not all things. Models must be modified to
explain things better.
Jeff Mathias mentioned a nice way of "simulating" continuous tone with digital
negative (which, maybe we can call it binary tones because it has only clear
or opaque). After you studied my illustration, think also about Jeff's
approach, and you will know that there is a "fundamental" difference among
digital negatives, silver negatives, and the mylar-diffused negatives.
Understanding all of those will help you decide which one is best suitable for
your process, material, and/or sometimes particular image.
PS:
America Online has a limitation on space, so I am always struggling about what
to put and keep there. My current plan is to put it just for 2 weeks, so
please go and check it out as soon as you can. If you agree with the model and
can use it in an educational environment, feel free to copy and distribute it
as long as the original copyright notice stays there (and you should not
charge anything except perhaps duplicating charge if you xerox the page). I
suppose you can do the same if you disagree with the model but want to show
your students how people can come up with ridiculous ideas. :)