Black Curtain in dreams
Cloth across a window — the chosen line between the inside and what may look in.
How black changes the reading
Black colour pulls the symbol toward the not-yet-known — depth, hiddenness, the part of the situation that has not yet come into the light. The dream is rarely warning you; it is showing you that there is more to the picture than the part you have been looking at.
The base reading of Curtain
A curtain in a dream is the dream's image of a privacy you control. Curtains do not lock the world out; they decide what may be seen at which times. The dream brings the curtain when you are negotiating how much of your interior life is on view. A drawn curtain is the dream telling you the privacy is intact and is your choice. A curtain torn down or stuck open is the dream noting that the screen you thought you had — between your private life and the people watching it — is no longer functioning, and someone is seeing in.