Science in Focus: Shedding Light: Lights, Camera, Action
Exploring the Photochemical Effect
II. The Science
In workshop 5 we explored the absorption of photons of light energy by the chlorophyll found in green plants. This energy was transferred to biochemical molecules such as sugar and starch. The transfer of light energy to chemical energy is called the PHOTOCHEMICAL EFFECT.
A camera receives light energy which is directed to the film inside causing a change in the chemicals on the film. This is also an example of the photochemical effect.
Black and white film is coated with light- sensitive chemicals containing silver. Color film is made of three layers of light-sensitive chemicals. Each layer reacts to photons of different color (different energy). The reaction to the chemcials on the film creates the images you see in your photos.
You might try exploring photograms with different sources of light. Do you get the same results? What factors do think affect the outcome of your photograms?
Explore additional Web resources to find out more about photograms in III. Resources.