129. Having produced a scale of nine neutral values, including White
and Black, the question arises as to the number of contrasts which it
affords, and it is easy to see that the number is thirty-six.
The vertical lines in the following diagram indicate the possible
contrasts of value in the Scale of Values. Counting the lines, we see
that the number of contrasts is thirty-six. Producing these contrasts,
we shall see what each one amounts to.
[Illustration: Diagram 1]