2. Creating a photograph with a film
camera is divided into three main
phases.
• Taking the picture
• Developing the negative
• Printing a positivehttp://retrothing.typepad.com/ph
otos/uncategorized/canonae1.jpg
3. TAKING THE PICTURE
• Photographic film has silver halide grains embedded in it (Jolly 3).
• When a picture is taken, a slide in a camera briefly exposes film to the light that comes in contact with
the lens.
• The photons from the light react with the silver halide to produce silver ions (Woodworth 6).
• The new ions create a “latent image”(Harrison 188).
4. DEVELOPING THE NEGATIVE
• The exposed film, containing the latent image, is soaked in a “developing agent that is actually a
reducing agent”(Woodworth 5).
• The reducing agent in the developer is pyrogallic acid (Harrison 219).
• The silver ions are reduced through the redox reaction with the pyrogallic acid and become visible silver
metal atoms (Jolly 3).
• Since the parts of the film that were hit with light reacted and now have visible silver, they appear
darker, forming an opposite picture called a negative (Jolly 4).
6. PRINTING A POSITIVE
• After the negative is dried it is put into an enlarger, which shines light through the negative onto a piece
of paper that, much like the film, has silver halide grains embedded into it (Jolly 4).
• The piece of paper is then developed just like the film and the silver ions undergoes the same redox
reaction as before to form visible silver(Woodworth 6).
• This time, however, the dark areas and light areas are opposite, so the correct ratios are
present(Woodworth 6).
• Essentially a negative of a negative.
7. IMPLICATIONS
Photography has become an everyday thing in
modern society, and it is important to understand
how it was achieved before the modern age of
digital photography.
http://upload.wikimedia.org/wikipedia/commons/b/be/Film_strip.jpg
8. WORK CITED
Harrison, William Jerome. The Chemistry of Photography. New York: Sovill & Adams Company, 1982. Print
Jolly, W. L. "Photography." Chemistry Explained. Advameg, 2014. Web. 15 Apr. 2014.
http://www.chemistryexplained.com/Ny-Pi/Photography.html
Woodworth, Charles. "How Photographic Film Works" 01 April 2000. HowStuffWorks.com.
<http://electronics.howstuffworks.com/film.htm> 29 April 2014.
