In many forms of spiritual practice and New Age “aura” is described as a coloured outline of a bodily energy generated from the soul or the Chakras (“force centers” in the body) emanating from the surface of an object or a body. Auras are allegedly only visible for specially trained persons with extended psychic abilities and a well developed third eye (Indian mysticism). However, auras can allegedly also be captured on film or by using special glasses.
Many of the so called aura readers claim to be able to read a person’s mental and emotional state as well as potential illnesses. However, aura readings have never been proven in any investigation outside the closed circuit of believers.
There are several ways to experience the phenomena of believing one is seeing an aura that are all explainable through science. Some of these include certain types of brain seizures, epilepsy, synesthesia, different visual disorders, psychedelic drugs and eye fatigue.
As far as creating auras around bodies on photographs or film, there are a couple of different techniques that can be used, such as thermal imaging or using different kinds of camera filters. Thermal imaging is not capturing an actual aura, but instead the temperature gradient around an object.
Auras seem to have no provable scientific mechanism nor any evidence for their existence.