Were women's clothes always dark at the time of "Macbeth" (the seventeenth century)?What I am trying to do is write down examples of the coursework...

Those are some astute observations you've made about the
use of color in Shakespeare's plays, but I am not certain that you can make much use of
the information.  Generally, the exact specifications of the costumes used by the actors
is not contained in the script itself...that is more the department of those putting on
the play.  As such, I don't think you can draw much significance from the fact that they
seemed to be wearing dark clothes.  While there might be some symbolism, and there may
be instances in which the clothing is described by the author, I'm inclined to think it
cannot be attributed to Shakespeare himself.

During
the Renaissance many colors were popular but black was, in some cases, very
fashionable:

1) Because it provided a great contrast to
colorful embroidery or jewelry.

2) Because those dark,
chromatic colors were easier to use on wool (and therefore less
expensive.)

3) Because the church frowned upon more
decadent colorings.

Renaissance fashion made use of many
different colors that could be made with natural dyes and each color had a certain
symbolism:

1) Green was the color of
love,

2) Gray for sorrow,

3)
Yellow for hostility,

4) Blue for
fidelity,

5) Red for
nobility,

6) Black for the lower
class.

Of course, over time, the meanings of these colors
changes.  In general, black/dark clothing would have been used to represent the
underclass or the unhappy.  It may be that some of this has carried over into the way
the plays are put on today.

Hope this
helps!