Film comes in all types both black and white and color and in all sizes from the tiny 110 to the large 220. For our class at Santa Cruz High School we work only with black and white film which is 35 mm in size.

FILM SPEED

This is the main division between types of films. Speed is how fast a film can capture an image when exposed to a minimal amount of light. This speed is given a calibration number so that we can compare films with each other.  This number is called ASA which stands for American Standards Association or it can be called ISO which is the same number but represented by the International Standard Organization.  These numbers can be from 1 to up over 32,000. The actual scientific process for determining that number is more than we need to know, it will suffice to say that the smaller the number the slower the film and the longer it will take to make an exposure.  A

Slow Speed Film

This is film with an ASA of less than 100. This type of film requires a lot of light to hit it to get an image. Because the grains of light sensitive material that make up the film are very small this type of film is called a fine grain film.  It is great for making large enlargements from a small negative.  It is also great for taking pictures in bright sun using a slow shutter speed like 1/30th second to emphasize motion blur or to force the depth of field in a photo to be made less sharp or simplified. Because these films require more light to get an exposure they tend to separate contrast differences better and thus appear to be contrastier than other films. These films are popular with nature photography and scenic photography buffs.

Fast Speed Film

This is film with an ASA of 200 to 800 or so.  The Tri-x film we use in this class is in this range. This film has a larger grain size in the light sensitive material and thus takes less light hitting it to record an image. This film can have a visible grain to it when making a print. This film has an exposure time of around 1/500th second at f16 in bright sun light. It minimizes motion blur because it requires a faster shutter speed. It also tends to make for better depth of field or included backgrounds because of the required f16 aperture. This is the speed range for most photojournalists.

High Speed and Ultra High Speed Film

This is film like T-Max 3200 that has an ASA of , you guessed it, 3200. This is a very, very fast film that requires very little light to make an exposure. These films are almost useless in bright sun because there is too much light. They would require a shutter speed of 2000 and an aperture of f22 which would require a very modern camera to accomplish.  This film is great for taking photographs under available light such as an indoor sports event. The film tends to have contrast problems because the detail in shadows will drop out while the highlights become a dominant part of the photo under low light conditions where reflected light is minimal. These are specialty films usually used by action photographers and photojournalists.