RADD 2501 Animal Insides Lecture - Film and Development

RADD 2501 Animal - Lecture 5 Lecture 5 Film and Development In this Lecture Know the composition of radiographic film Know(basically)how a latent

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Lecture 5 Lecture 5: Film and Development In this Lecture ¾ Know the composition of radiographic film ¾ Know (basically)how a latent image is formed ¾ Know the steps of development ¾ Understand proper safelight use. So, you are holding a perfectly exposed piece of radiographic film in your hand. Now what? Drop it off in the Kodak bin at Wal-Mart and get charged and arm and a leg for a bunch of crummy 4x6 inch prints that cost you $12.50 because you accidentally marked the “duplicates” box. Of course not. You will develop them yourself. Don’t know anything about developing film…no problem. Follow the steps below and you will be on your way. The polyester you can’t make into a bowling shirt E very good discussion of radiographic film development starts with a discussion of the physical characteristics of radiographic film. I am not yet famous enough to buck this trend so here goes. Radiographic film consists of two major components: ¾ A polyester base that provides support. This base gives radiographs their blue tint ¾ Film Emulsion: The emulsion is a thin layer of stuff on top (actually both sides) of the polyester base. It is the part of the film that actually records the image. It is composed of two main ingredients: o Silver Halide Crystals: Silver Halide is the light sensitive material in the emulsion. The “halide” in silver halide is mainly bromide.
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o Gelatin: Gelatin keeps the silver halide grains evenly dispersed and prevents clumping of the grains.
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You can think of the emulsion as being kind of like a Jell-o mold…gelatin with particles of fruit cocktail floating in it. But wait. There are many types of Jell-o mold. I think they are all equally disgusting, however, some people like their Jell-o mold with little bits of fruit. Some like bigger chinks of fruit. Some like carrots instead of fruit. Different types of photographic film (there are hundreds) vary in a similar way. The size, shape, composition, and number of particles of silver halide affect the characteristics of the radiographic film. The major effects that altering the emulsion have are on film are film latitude, film contrast, film speed, film detail, and light color (spectral) sensitivity . When you go to purchase film you will have to chose between a staggering number of different films that vary in these 5 parameters. These parameters of film response alter the type of the film in the following ways: Film Latitude: Film latitude refers to the amount of error you can make when exposing a film and still get a good image. High latitude film means that you can mess up pretty bad and still have an reasonably exposed film. The trade off is contrast. High latitude film has low radiographic contrast. Conversely, low contrast film has more shades of gray. Film Contrast: Contrast is a complicated subject and is affected
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This note was uploaded on 11/22/2011 for the course RADD 2501 taught by Professor Sandyeverage during the Winter '11 term at Life Chiropractic College West.

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RADD 2501 Animal - Lecture 5 Lecture 5 Film and Development In this Lecture Know the composition of radiographic film Know(basically)how a latent

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