Do you know which raw materials are required for producing photographic film? Or, how the changing prices of these goods affect your final cost as a consumer?
The raw materials for film production are some of the world’s most mined natural resources, and thus subject to swinging market prices. Let’s take a closer look at the layers of photographic film and the goods and processes that go into manufacturing the final product. But first, a question:
(See the bottom of this post for the answer. )
Here is an example of the layers you find in a typical photographic film – the kind you might use for developing Western blots in your lab.
The top layer, the layer that reacts to light exposure, is the Photosensitive Emulsion Layer. This layer is dull and tacky, and is produced by dissolving silver bars in nitric acid to produce silver halide grains. These photosensitive grains are then suspended and bound in a gelatin solution made from animal hide and bones.
The middle layer, the Film Base, is smooth and shiny. There are three major types of film bases:
- Cellulose nitrate,
- Cellulose acetate, and
Cellulose nitrate is not commonly used because it is highly flammable. Acetate film was most commonly used between 1920 and 1970. But, because acetate base tends to deteriorate over time and with the invention of polyester, a move toward a new type of film was made in the 1950s. Polyester film, the type primarily used today, is composed from crude oil, or more specifically, petroleum byproducts.
The final layer is the Anti-Halation Layer. This layer prevents halo artifacts from refracted light and is composed of an opaque, heavy color dye. This layer is washed away during processing to reveal a transparent negative, which, in Western blotting, is the final data image.
Stay tuned for more information on how the prices of silver and crude oil affect the prices of film.
- What is the Future of Film Use for Western Blot Imaging?
- The History of Film. What Does It Tell Us About The Future of Using Film for Western Blot Imaging?
- What if Film Was No Longer Available? How Would You Capture Your Western Blot Images?
Answer to poll question: Yes, photographic film is composed of everything from petroleum to cellulose from animal byproducts. Did you guess correctly?.