FILM
FILM TYPES | ACCURACY | LATITUDE | FILM SPEED | PROCESSING | BALANCE | FORMAT | GENERATIONS
FILM TYPES
Color Negative Film, typically labeled "Process C-41", must be printed or scanned to render a positive image on paper or as an electronic file.
Black and White Negative Film must be printed or scanned to render a positive image on paper or as an electronic file.
Positive Film, typically labeled "Process E-6", renders a transparent positive image once it is processed. Positive film is usually referred to as Slide Film.
FILM ACCURACY
Color Negative and Black and White Negative Films are printed or scanned, therefore they may be adjusted or altered in the process. To produce accurate results in the printing or scanning process, take a picture of an object, such as a colorful bandana, in the lighting conditions you are photographing and have the object available to compare with in the imaging stage.
Positive Film, or Slide Film, when processed under quality-controlled conditions, produces highly accurate results. The image you expose in the camera is the image you get once the film is processed. If you make well-controlled accurate exposures, you will be pleased with the results. If you over or underexpose Slide Film, you will realize the need to improve your ability.
The benefits of Slide Film include: Accurate reproduction in printed materials; Highest level of consistency when matching with other images produced under the same conditions; Highest quality source material (First Generation) for scanning; Best presentation material to gage ability and understanding of camera use and lighting.
FILM LATITUDE
Latitude is the range of exposure over or under the correct exposure, as calibrated to 18% reflected light from Middle Gray, that film can handle before it can no longer render details. Color Negative Film has the highest latitude of 5 to 6 stops, while Positive Film, or Slide Film, has a Latitude of only about 3 stops.
Being able to identify the difference or range of light in the photograph you are making is extremely important. You may determine that the range between bright and dark is too extreme to make a worthwhile exposure. You may realize you have to sacrifice detail in the dark areas to avoid severely overexposing the bright areas. You may chose to underexpose dark areas to render no detail (so they become silhouettes shapes or outlines). Or, you may find it to be a narrow margin, in which case you can use creative judgement to determine which areas of the image you are willing to underexpose or overexpose.
If you must photograph a subject with a wide discrepancy in light intensity, where the range of meter readings varies widely, and if you have no way to adjust or control the light, you should make the exposure using Color Negative Film. One approach is to underexpose the dark area of the image slightly, leaving the brightest area of the image overexposed, and request a Custom Print from a Professional Photo Lab. It may also be helpful for the lab to "Pull" the film one stop.
With Black and White Film, Latitude issues may be corrected or improved in the film processing stage and/or in the printing stage. If you are extremely serious about controlling the range of contrast in the negative, and ultimately the print, you may want to learn the
There are other methods you may use with Black and White Negatives to control contrast. Using multiple Contrast Filters and Variable Contrast Paper will be discussed in
FILM SPEED
Film types are characterized by fast and slow film speeds. For example, 50 and 100 are considered slow, and 400 and 800 are considered fast. Slow films are capable of rendering sharp detail and wide color saturation better than fast films.
Fast films are often used when extra graininess is desired. The effect can be enhanced by overexposing or overprocessing the film. Additionally, film exposed to heat or stored at temperatures above the recommended storage temperature may reveal increased graininess.
Grain that seems subtle in a small Proof or Machine Print, typically 4" x 6", will be more evident as the print size is increased. For more considerations, see
It is possible to determine your Film Speed needs simply by understanding the amount of light you are working with and considering the Aperture and Shutter Speed you would like use. See
PROCESSING
Color Film is labeled to be processed as E-6, for Color Positives, or C-41, for Color Negatives. It is possible to adjust the process. If film is overexposed, it may be "Pulled" one, two or three stops as needed. If film is underexposed, it may be "Pushed" one, two or three stops as needed. See
If you have photographed many rolls in the same light conditions, you may want to process one or two rolls first to determine that you are satisfied with the results. You may then consider "Pushing or "Pulling" the film process, if you need to correct a consistent error in metering. As well, if you realize you are overexposing or underexposing film as you are using it, you should make a note on the Film Cassette and inform a Professional Photo Lab. If you have mistakenly overexposed the Color Negative Film one stop, the lab may suggest normal processing because the latitude of the film can handle the overexposure, whereas, Color Slide Film over or underexposed will need to be corrected to be usable. If you have the ability to expose a test roll in the same lighting conditions using the same camera settings, you will have a useful tool for determining the level of correction needed to process your important film.
Adjusting the film in processing will change the saturation. If you plan to Push or Pull film, you should experiment with the process, so you will be prepared for the results. The best results will usually come from accurate exposure of the film. See the next section, Exposure.
FILM BALANCE
Films are balanced to different light temperatures (essentially the shift in color produced by different light sources). The most common Film Balance is "Daylight", which is intended for use in daylight and with nearly all Flash or Strobe units. The other balances include Tungsten, Fluorescent and Infra Red.
Tungsten and Incandescent light bulbs are not common (as Fluorescent and Halogen lights are most commonly used in nonresidential environments), but Tungsten Film can additionally be used with inefficient light sources, such as candle flame. When used in Daylight conditions, Tungsten Film renders blue tinted scenes, as that is the shift it normally makes to correct for extremely yellow light sources.
Fluorescent Film is virtually useless as there are now many temperature balances in Fluorescent tubes, including Daylight balance.
Infra Red Film records Infra Red Light, a light source not visible to the human eye. It must be loaded into the camera in darkroom conditions to avoid being prematurely exposed to Infra Red Light. There is a necessary shift in the focus required to make sharp pictures. Older lenses indicated the necessary shift with a red dot, found near the mark that indicates focus distance for visible light.
FORMAT
Large film can render more detail than small film when compared under equal conditions. 35mm Film is the smallest common format. Medium Format Film is typically called 120, or 220 for the longer roll, which has a thinner Film Base. The image frame size created by Medium Format Film is 2.7 times larger than 35mm, when the frame is 6cm by 4.5cm. Many Medium Format Cameras make even larger frames, such as the 6cm by 6cm square fame of most Hasselblads, and the 6cm by 7cm frame of the Pentax 6x7. Larger formats include 4" by 5" and 8" by 10".
GENERATIONS
In the traditional film process, duplication creating in new Generations can result in degradation of the image. The original Transparencies or Negatives are the First Generation. As film is translated to new materials or media, new Generations are created. A Slide may be made into an Internegative (Second Generation) and then a Third Generation Print. A Print from an original Color Negative may be made into a Copy Negative (Third Generation, because the Print was the Second Generation) and then into a Forth Generation Print. This is sometimes necessary, however unfortunate, when negatives are lost or damaged.
Digital Files, such as Digital Images or Digital Scans from Film, may not degrade as they are regenerated unless changes to the files are saved. Digital Files that are resized may suffer from Interpolation and it is generally impossible to exceed the maximum resolution of the file with acceptable results. Calibration can be a major problem with the reproduction of Digital Files and can severely degrade image quality.
HIFC FIELD GUIDE | PHOTOGRAPHY CLASSES | info@houstonculture.org
Updated Oct. 2001