In general terms, darkness represents the absence of light, which means that people cannot correctly visualize the objects that are around them, including other people. On the other hand, this term has always been associated with the negative, with the evil. For Christians, the devil and hell are elements of darkness.
For science, darkness is achieving a partially low level of light. Where those objects that lack light, tend to reflect fewer visible photons than other objects, so they will present an opaque appearance.
For poetry, darkness is seen as an element that reflects sadness, depression, evil. Psychologically, darkness can have a strong impact, so much so that it can generate melancholy, nostalgia in people, especially in those subjects who suffer from depressive disorder. It is important to note that for people who suffer from phobias and fears, darkness can be a somewhat problematic issue, since it can increase those feelings.
On an artistic level, darkness can be used to give greater intensity or contrast with light. In painting, darkness is used to form guide lines and voids, among others. These figures are created to attract the eye towards the painting, since the shadow adds optics.
For some, the darkness can be gloomy, an accessory to many dangerous acts of crime, since bandits often commit their misdeeds during the dark. However, for others the darkness symbolizes passion, the meeting between lovers who use the darkness to release the reins of their love. Many couples in love prefer dates in the moonlight, considering it the perfect setting for a romantic night.