The Principles of Color Film
In photography, color film is a modern phenomenon that allows for color pictures to be taken and developed into prints. The principles of color film are based on the human eye’s ability to perceive color. The human eye has three ‘cones’ in the retina that are sensitive to red, green, and blue light. These cones interpret short wave light as blue, medium wave light as green, and long wave light as red. The perception of color is dependent on the balance and intensity of the three wavelengths of light.
Color film captures the light as it is reflected or transmitted through an optical system. It works by separating the wavelengths of light into its three primary components, which it then transfers to a photosensitive layer of the film. This layer records how much of each of the primary colors are present in the light, resulting in a three color record of the scene.
The most common type of color film is based the principles of subtractive color mixing. This film has three layers, each containing a different ‘dye cloud’. The first layer contains yellow dye clouds which absorb blue and green light, leaving only red light to be recorded by the blue sensitive layer below it. The second layer contains magenta dye clouds which absorb green and blue light, leaving only red and blue light to be recorded by the green and blue sensitive layers respectively. The third layer contains cyan dye clouds which absorb red and green light, leaving only blue light to be recorded by the blue layer.
When the film is developed, the three primary color records are transferred to three matrices and are then aligned, creating the full color image. This is done by exposing each of the three color records onto a different metallic or photopolymer printing plate. The printing process is then used to create the composite image by transferring the images from the photopolymer plates to the paper.
In order to accurately print a full color image, certain principles need to be adhered to. The amount of exposure of each color record needs to be carefully balanced so that the printing is true to its original form. The color balance of the viewing light is also an important factor, as the colors of the film will appear different under different conditions. The viewing light should be consistent so that the colors of the print will be seen as intended.
In order to take full advantage of the capabilities of color films, it is important to understand the principles on which it is based. Its sensitivity to the three primary colors of red, green, and blue light as well as the principle of subtractive color mixing are key to producing accurate and beautiful photographic prints. By paying attention to the color exposures and the color balance of the viewing light, you can ensure that you will get the best results possible out of the film.