Processing. If you used a camera, then the next step is to process your movie. A properly exposed film is distinguished from a film not exposed solely at the atomic level – minute chemical changes forming an invisible or "latent" image.
The development of chemicals then must affect your film in the dark to amplify the latent image into a much more substantial and permanent normal light. You apply these chemicals in liquid form; each solution has a special function when applied to the appropriate film. With most black-and-white films, for example, the first chemical solution develops light-struck areas in black-silver grains. It is followed with a solution that dissolves ('fixed') the unexposed parts, leaving these zones like a clear film. So, the result, having washed the byproducts and dried them, is a black and white negative, depicting the brightest parts of your subject as the darkest light grey or transparent parts.
A similar routine, but with more complex chemical solutions, is used to transform the color film into color negatives. Color slide film requires more treatment steps.
Firstly, a black and white. The negative developer is used, then the rest of the film, rather than being normally fixed, is developed in color to create a positive picture in black silver, and dyes. You are eventually left with a positive, color-picture dye slide.
Printing negatives. The next step in production is printed, or more commonly enlarged. Your image in the movie is set up in a vertical projector called a magnification.
The magnification lens forms a picture, of almost any size you choose, on light-sensitive photographic paper. When exposed, the paper receives more light from the bright areas of your film than from the denser parts. The latent image that your paper now transports is then processed into chemical solutions that largely resemble the steps required for the film. For instance, a piece of black-and-white paper is exposed to black-and-white negative film, and then developed, repaired, and washed to show a negative from the negative, which is a positive image—a black-and-white imprint. The color paper after exposure goes through a color development sequence, whitening, and fixation to form a negative color of a negative color. Other materials and processes provide color printouts of slides.
An important feature of printing (apart from enabling changing the size of the image and running many copies) is that you can adjust and correct your photo. Undesirable parts near the edges can be trimmed, changing the proportions of the image. The selected areas may be brightened or darkened. Working in color, you can use a wide range of color filters to enlarge to "refine" the color balance of your impression or to create effects. With the experiment, you can even combine parts of multiple movie images in print, shape images that are part-positive, part-negative, and so on.
Color and black and white. You have the choice between various types of film for color or black-and-white (monochrome) photography.
Visually, it is much easier to photograph the color than black and white because the result looks closer to how the subject was looking in the viewfinder. Differences between the appearance and color of the photograph should be considered. But this is generally Less difficult than predicting how the colors of the subject will translate into monochromatic tones.
Black and white are considered less realistic, creating a gap between the «real» and its representation, and for this reason calls upon several beginning and advanced photographers, wrongly or rightly considered more interpretive and subtle.
Color films, paper, and chemical processes are more complicated than black and white.
Therefore, it took almost one hundred years after the invention of photography for reliable color printing processes to appear. Even then, they were costly and laborious to use, therefore until the photographers of the 1970s learned their craft in black and white and worked up to color, there are exceptions to that rule, such as William Eggleston.