How is the emulsion coating applied to the film?
The coating of a film is a layer of emulsion containing microscopic light-sensitive silver halide crystals.
The emulsion Coating is applied to the film base (or plate) to sensitize the surface and allow for the photographic process to be made possible. There are two ways to coat a film: manually and mechanically.
Manually: the liquid solution is steadily poured onto the plate. The plate has to be cleaned before the emulsion will make contact. Without leaving any fingerprints on the plate, a small amount of liquid emulsion must be carefully taken with a pipet and poured uniformly onto the plate. Then with a slight tilting movement, spread all over the surface.
Mechanically: For industrial coating, a machine applies the liquid form of the emulsion. The speed, precipitation and direction with which each component is mixed must be kept under strict control as it will determine the consistency of the paste and the quality of the film.
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What is the difference between panchromatic and orthochromatic film?
Orthochromatic film is made with blue-sensitive silver halide crystals, while panchromatic film adds other chemicals to increase the film’s sensitivity into the green and red parts of the spectrum.
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How many layers does a film emulsion have?
There are several layers in a film emulsion and their characteristics vary with each manufacturer.
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What are Silver halide crystals?
A silver halide is a chemical compound that forms between the element silver and one of the halogens. When the crystals are exposed to light they react and form latent images.
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How does film work?
A photograph is the final result that occurs when a chemical reaction exists between light and sensitive silver grain compounds.
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What is photographic film made from?
Film is composed by two main parts, the base and the emulsion. The film base is usually made of cellulose triacetate, acetate, or polyester. The emulsion is the active ingredient that will capture the final image.