Much of what being a film artist means goes far beyond just capturing an image. Instead the resulting film image has to be prepared in just the fashion you want so that the audience is privy to visuals that are intended. To this end there is no limit as to what you can do before, during, and after actual production. If you are using actual film stock you can go right down to affecting the film itself, which is a very direct way of creating an alteration.
Filmmakers and directors should try to get a good knowledge of all of the video equipment and film technology they are working with. How the film is processed and developed is part of this and many film artists will go as far as to do some of this themselves. If you are looking to add a great amount of contrast to your film look you can go through several processes both in production and during non-linear video editing, but there is another one that can be done during the film development phase of post-production. This process is call Bleach Bypassing.
Bleach Bypassing is a reference to a type of bleach is normally using in the processing of moving film. This bleach removes little silver granules from the film stock. If you use a Bleach Bypass then you simply remove the bleach from the processing liquid. The silver ends up being retained after Bleach Bypassing and the image has an elevated level of contrast and washed out bright areas. It looks as though the colors have been partially desaturated, and results in what can be described as a combination of black and white and color film.
This is a very stylized look that has been often used in surrealist films, horror films, urban environments, and a whole host of other specialities. The Bleach Bypassing process is also referred to as Skip Bleach, obviously because you are skipping the bleach. This is not used often in major productions anymore because this affect can easily be done in non-linear video editing software. You can usually do this by combining certain video effects, color correcting techniques, and a small percentage of video desaturation.