There are 2 main types of film: terrestrial and aerial. Terrestrial film is used in everyday 35-70 mm cameras, both indoors and outdoors. Aerial film is made specifically for 70 mm, mapping, or reconnaissance cameras. Both types of film come in either black & white or color formats.

Black & White Film

Black & white film can either be panchromatic (detects visible light) or infrared (IR). The panchromatic film is usually used in combination with a yellow filter, which gets rid of most of the atmospheric haze and gives you a clearer picture. These types of photographs are called "minus-blue photographs." The biggest drawback to using filters is that shadows are completely black and no detail can be seen inside of them. This can be offset by the time of day the camera is flown. With panchromatic film, it can be difficult to distinguish different types of vegetation, such as tree species. It is usually the least expensive film to purchase.

To obtain a "true infrared photograph," you can combine an infrared-transmitting filter (eliminates all visible light) with an infrared black & white film. These photographs can be used to distinguish different types of vegetation. Since water does not reflect IR light, the photographs can also be used to identify water supplies and areas with moist soils.

True/Normal Color Film

True, or normal, color photography is useful because it depicts the landscape in the colors that the human eye perceives. It it useful for finding water sources and large areas of vegetation damage, computing acreage and percent canopy cover, and many others applications. True color films are not much more expensive than black & white panchromatic film. If choosing to use true color film, it is best to plan a flight at low- to mid-altitude and to choose a combination of filters to decrease atmospheric haze.

Color Infrared Film

Color infrared (IR) picks up near IR reflectance that the eye cannot see. This film is extremely useful for vegetation composition mapping and analysis. In the image above, you can see the response of 3 types of vegetation to near IR light. The healthy vegetation will be the brightest red in the photograph (green line), with stressed (red line) and severely stressed (yellow line) being successively less bright. If you need to pick out stressed vegetation, comparison of photographs that capture the near IR and the short-wave IR (satellite imagery) would be best.

Sometimes, stressed vegetation can show up as yellow or white in photographs, and defoliated vegetation can appear blue or green. Color IR photography is also useful for detecting stressed vegetation before it can be seen by the naked eye because of the slight loss of green coloration (IR reflectance). As with true color photography, a yellow filter is usually used and shadows will appear black, hiding all detail within them.

Avery, T.E. and G.L. Berlin. 1992. Fundamentals of Remote Sensing and Airphoto Interpretation. 5^th ed. Upper Saddle River, Prentice-Hall, Inc.