Kirlian photography refers to a form of photogram made with a high voltage. It is named after Semyon Kirlian, who in 1939 accidentally discovered that if an object on a photographic plate is connected to a source of high voltage, small corona discharges (created by the strong electric field at the edges of the object) create an image on the photographic plate.[1]...
Kirlian made controversial claims that the image he was studying might be compared with the human aura. An experiment advanced as evidence of energy fields generated by living entities involves taking Kirlian contact photographs of a picked leaf at set periods, its gradual withering being said to correspond with a decline in the strength of the aura. However it may simply be that the leaf loses moisture and becomes less electrically conductive, causing a gradual weakening of the electric field at the drier edges of the leaf...
The accepted physical explanation is that the images produced are those typically caused by a high voltage corona effect, similar to those seen from other high voltage sources such as the Van de Graaff generator or Tesla coil. In a darkened room, this is visible as a faint glow but, because of the high voltages, the film is affected in a slightly different way from the usual. Color photographic film is calibrated to faithfully produce colors when exposed to normal light. The corona discharge has a somewhat different effect on the different layers of dye used to accomplish this result, resulting in various colors depending on the local intensity of the discharge. [6]