Introduction What is photography? The history of photography What this site will do for you Light: The most important element Why light is important to a photograph The many types of light Controlling light in your pictures The camera The basic function Types of cameras Choosing the right camera Putting the image together: the Lens How the lens bends light: a tutorial A brief introduction to apertures The variety of lenses Choosing a lens Exposure: a film tutorial How film records an image Understanding film speed Print vs. Slide film Film recommendations Taking Pictures Depth-of-field Apertures and shutter speeds Composition and experimentation: the basics Metering: when you can't guess The many types of picture-taking Photography with a point-and-shoot Accessories Tripods: for when you can't stay still Lens filters Post-processing: after development Scanning photos The digital darkroom Photo and equipment storage
Film is probably the most complex element of photography, though it is the second-most important, besides light. Though you would have to be a super-advanced mathematician to understand it all, there are only a few things you must know.
How photographic film works
Before we continue with learning about how film operates, you must understand a few factors of light. Light is a visual portion of energy called electromagnetic energy, which includes X-rays, infrared, and ultraviolet radiation. The part of electromagnetic waves that is visible to our eyes see long wavelengths as red, short ones as violet, as well as orange, yellow, green, and blue in the middle of it all. If you are feeling confused, try remembering about the colors of a rainbow or prism. The colors on it are the colors that I explained above, the colors of the visible spectrum.
Well, guess what? Film reacts to those lights. For example, black-and-white film reacts to short wavelengths, mainly light perceived as blue. If you are taking a picture of something blue, red, and orange, the blue part would be too light, and the red and orange part would look very dark. So, as photographers found out about this problem, they added dye sensitizers to the film to correct the color. Film today, unlike older black-and-white film, is sensitive to all colors in the spectrum. Today’s film is usually coated with three emulsions, which are usually cyan, yellow, and magenta. Each one of the emulsions is sensitive to only one of light’s colors. With the emulsion layers, there is also a dye layer, which makes a color that is equivalent to what a human eye sees.
Conclusion
If you felt totally lost, don’t think too much of it. It is not easy to simplify the operation of film, and it would take a 500-page book to explain it all. I just wanted you to get at least a little bit of an idea of how film works. Knowing everything about film is not necessary to be a good photographer, though knowing a little more wouldn’t hurt. Next up, we will learn about the speed of film. Don't worry, this won’t be very complicated.