filmlesson1

Film Basics

Go to any camera store and their will be dozens of different film choices for the consumer. For many people choosing film can be a very confusing and mysterious process. Often students will have no idea in what film they should choose or what a certain film might be used for. Hopefully after this short lesson the mystery of film will become a little more clear.

Lets start by looking at the basics of how film works.

When light strikes film, it produces a chemical change in silver salts located in the film's emulsion.
This change can not be seen until developer is applied to the film.
Exposed silver salts turn into metallic silver, producing dark areas of density.
The more an area was exposed to light the darker that area will appear on the film.
Color films use a special dyes that bind themselves to the metallic silver.

Film is made of three different layers. Film starts with a base material usually made out of thin plastic. The plastic is coated with emulsion layer that is embedded with silver nitrate or silver chloride. The back of the film is made up of a antihallation backing that absorbs any light that did not get exposed onto the silver salts.