Electroluminescence is the conversion of electric energy directly into visible light. Electronic flash is artificial lighting produced by an electronic discharge in a gas filled tube. A single tube can produce a large number of flashes. Electronic shutter is a shutter system timed by electronic rather than mechanical means. Electrophotography is the creation of images by alteration to the electrical properties of the sensitive material as a result of the action of light.
Element is a single lens shaped piece of glass that forms part of a compound lens system.
Elon is another term for Methylaminophenol sulfate. It is more commonly known as metol. Emerson, Peter Henry 1856-1936. Emulsion is a light sensitive material which consists of a suspension of silver halides in gelatin. Emulsion side is the side of the film coated with emulsion.