Edge
A boundary in an image between areas with different tones.

Edge enhancement
Image-processing technique that emphasizes the appearance of edges and lines.

Ektachrome
A Kodak color positive film.

Electromagnetic radiation
Energy propagated in the form of and advancing interaction between electric and magnetic fields.
All electromagnetic radiation moves at the speed of light.

Electromagnetic spectrum
Continuous sequence of electromagnetic energy arranged according to wavelength or frequency.

Emission
Process by which a body radiates electromagnetic energy. Emission is determined by kinetic
temperature and emissivity.

Emissivity (e )
Ratio of radiant flux from a body to that from a blackbody at the same kinetic temperature and emissivity.

Emittance
A term for the radiant flux of energy per unit area emitted by a body. (Now obsolete).

Emulsion
Suspension of photosensitive silver halide grains in gelatin that constitutes the image-forming
layer on photographic film.

Energy flux
Radiant flux.

Enhancement
Process of altering the appearance of an image so that the interpreter can extract more information.

EROS
Earth Resources Observation System.

ESA
European Space Agency, based in Paris. A consortium between several European states for the development of space science, including the launch of remote-sensing satellites.

Evaporative cooling
Temperature drop caused by evaporation of water from a moist surface.