Ben Long at CreativePro.com has posted an excellent piece on why all images are manipulated artwork. Manipulation begins with the decision to frame a photograph all the way through the editing and final printing. Doesn’t matter who the photographer is, what camera equipment is used, whether it is digital or film. It is all art and therefore subjectively edited.
There are a few additional points that might be worth mentioning related to this. Many well known photographers manipulated their images. Most famous of all is Ansel Adams, whose Zone System is used extensively. The technique was developed for black and white film and has been extended to film of all types. The entry on Wikipedia says it well.
An expressive image involves the arrangement and rendering of various scene elements according to photographer’s desire. Achieving the desired image involves image management (placement of the camera, choice of lens, and possibly the use of camera movements) and control of image values. The Zone System is concerned with control of image values, ensuring that light and dark values are rendered as desired. Anticipation of the final result before making the exposure is known as visualization.
There are multitudes of different films. Well, there used to be. When younger, I worked with Kodak Plus-X (ISO 125) and Tri-X (ISO 400), and occasionally Pan-X (ISO 32). Each of these could be ‘pushed’ or ‘pulled’ for different reasons and final effects, including contrast, grain, and tonal range. Each required different development processes that were temperature dependent. Although they are considered panchromatic, each of the films seemed to have different light responsiveness across the white light spectrum. I’m not sure if that is accurate, but it seems so.
Once developed, they had to be printed, a process that requires selection of the enlarger, the paper (type of fiber, warm/cold, low/hi contrast, gloss/semi-gloss/flat), development workflow (lots of chemicals), and more. A final printed image is always an interpretive effort, balancing overall exposure, dodging and burning key sections, and the like. For an example of high quality, pre-Photoshop image manipulation, check out Fujichrome Velvia in 1990 and it rapidly became popular. It is known for having saturated (some say supersaturated) colors, which makes it great for landscapes but limits its use in portraits.
The list of artistic choices extends to cameras (35mm, medium, large format), lenses of all sorts, filters, etc. Far, far too many choices are made in creating a pleasing image for there to be an absolute ‘truth’ to photographic art.