or 70mm for 16 x 20 inch or larger prints. There are many  experienced  aerial  photographers,  and  because  of varying experiences, they may have very different opinions. Most favor a medium-format camera when prints are required. Medium-format cameras are easy to handle in confined spaces—the back seat of a jet aircraft, for instance. They are relatively small and convenient  to  use.  With  careful  processing  and printing, almost any size of print can be made from the negatives produced by a medium-format camera. Excellent results may be obtained by using a 35mm camera; assuming, of course, you handle the film carefully during processing and printing. Because of the  variety  of  interchangeable  lenses,  small  size,  ease  of handling, and large number of exposures, the 35mm camera is preferred by many Navy Photographer’s Mates. FILM  SELECTION Aerial  film  is  designed  for  high-altitude photography and does not yield better results than conventional  films  at  low  altitudes.  Remember  that most hand-held aerial photography is performed at low altitudes.  There  are  several  factors  that  you  must consider before selecting a particular type of film. The first, of course, is the end use (purpose) of the pictures. Do you need black and white or color; prints or slides? Other important factors are as follows: Weather  and  haze  conditions Lighting conditions Special  purpose  film  (color,  camouflage detection, and infrared (CDIR) Special filtration Processing requirements or capabilities Black-and-White Panchromatic Film For  an  aerial  assignment  requiring  black-and-white prints  only,  you  should  first  consider  a  black-and-white film, such as Kodak Technical Pan (Tech. Pan.). This and other similar types of film are fast enough for most aerial work when the weather is good and the subject is well-lighted.  The  extended  red  sensitivity  of  Tech.  Pan. also  helps  to  penetrate  haze.  This  film  is  readily available and convenient to process. Tech. Pan. has excellent  resolution  and  the  extreme  fine  grain  required to make high-quality enlargements. Special types of film designed for reconnaissance are also available. These films are normally available only in rolls, and they range from 70mm to 12 inches wide.  These  films  are  characterized  by  their  sensitivity, base  type  and  thickness,  speed,  resolution,  and granularity. These films also have an extended red sensitivity to aid in greater haze penetration. Although  black-and-white  prints  can  be  made  from color  negatives,  it  is  better  to  use  black-and-white  film. Black-and-white film is superior to color emulsions in their ability to record image detail. Haze and contrast control are easier to achieve with black-and-white film than with color film (fig. 4-14). Black-and-White Infrared (IR) Film In  aerial  photography,  black-and-white  infrared (IR) film offers several advantages over panchromatic film. Primarily it provides higher contrast and the unique ability to record detail through haze. Thus black-and-white IR film should be considered when aerial views must be taken under such conditions. This type of film can record more detail through haze than can be seen with the human eye. The sensitivity of IR film extends to approximately 900nm with maximum IR sensitivity from approximately 760nm to 880nm. It is particularly useful when extreme distances must be covered, such as high-altitude photography, or when a high angle of view is required for high obliques. Before selecting a black-and-white IR film, you should check with the person for whom you are doing the work Prints made from black-and-white IR negatives appear quite  contrasty  because  blue  sky  and  water  are reproduced almost black (fig. 4-15). Growing crops and deciduous trees appear white in photographs and most evergreens record darker. If such prints meet the requirements of the requester and IR film is the best choice, by all means use it. However, keep in mind that when black-and-white IR film is used, you must filter out blue and ultraviolet radiation with a red filter, such as a Kodak Wratten No. 25 or equivalent, for best results. Color  Negative  Film Color negative film, such as Kodak Vericolor III Type   S,   may   be   used   to   provide   color   and black-and-white  prints.  However,  when  available,  film, such as Kodak Vericolor HC, is a better choice. Kodak Vericolor HC provides better results because of the 4-14