What is an image? An optical appearance; a mental representation an idea or conception. The term image may be applied to a picture such as a photograph a painting or a sketch which has a real physical existence. May also be applied to an idea or concept which has a mental rather than physical existence. Visual images are of two types; Real Images- those having a real physical existence such as a photographic image. Mental …showed first 75 words of 943 total…

…showed last 75 words of 943 total…or 'halo' around the proper image. This is known as halation and is a cause of unsharpness in the image. Single Emulsion Film; Single coated, screen-type x-ray film is used inside a cassette housing just one intensifying screen. The single coated films employed possess a type of emulsion similar to that used with duplitised film, but the emulsion coat is applied only to one side of its base. Magnified cross-section through single sided emulsion film