How many layers does a film emulsion have?
There are many kinds of photographic film, and their characteristics vary with each manufacturer. Photographic film is made up of several layers. The part that enables an image to be captured is called the emulsion layer. It is composed of a mixture of gelatine and light-sensitive silver halide crystals.
The emulsion itself is made up of even more layers. Each of these layers of emulsion is responsible for capturing one of the three primary colors, blue, green and red. Silver halide crystals have an innate sensitivity to blue and UV light, therefore the blue sensitive layer is placed at the top.
Within each layer there are also dyes that coat the silver halide crystals and enable them to only absorb the correct wavelengths. These are called sensitizing dyes.
In some cases, we can find other layers at the top and bottom of the emulsion, that protect against scratches and UV light. While some films, mostly for cinematic purposes, include an anti-halation layer.
Cover photo credit: novakmisi
Anything missing?
Can’t find an answer to your question? Or do you have some useful advice to add to one of our courses? We want to build the world’s largest analogue learning space, so please send any further requests or information to school@lomography.com and we’ll take a look!
More Courses
-
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.
-
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.
-
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.
-
How does film work?
A photograph is the final result that occurs when a chemical reaction exists between light and sensitive silver grain compounds.
-
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.