The process of Kirlian photography was named after Semyon and Valentina Kirlian in 1939. Kirlian photography is the corona discharge phenomenon, which takes place when an electrically grounded object discharges sparks between itself and an electrode generating the electrical field. When these sparks are captured on film they give the appearance of coronas of light. The discharges can be affected by temperature, moisture, pressure, or other environmental factors.