haze filter includes contrast and correction filters. When contrast  and  correction  filters  are  used  for  haze penetration, they may be considered special-purpose filters. Although contrast filters can be used for cutting haze, these filters affect the gray tone rendering of colored objects. The contrast and correction filters that absorb the shorter wavelengths are the most effective. The recommended contrast and correction filter colors, in the order of greatest to least effective for haze penetration,  are  as  follows: Red Orange Yellow Green The use of an infrared sensitive black-and-white film with an infrared filter provides the greatest haze penetration  of  all.  Special,  visually  opaque  infrared filters  completely  absorb  the  scattered  ultraviolet radiation and the visible light that produce haze. This absorption by an infrared filter allows the scene to be photographed   entirely   with   unscattered   infrared radiation. An infrared sensitive black-and-white film without an infrared filter, or at least a red contrast filter, is  not  effective  for  haze  penetration.  Infrared black-and-white film is sensitive to ultraviolet radiation, violet, and blue light as well as infrared radiation and red light. The gray tone rendering of a colored subject in  a  black-and-white  print  produced  from  an  infrared negative  is  greatly  distorted  or  contrasty. The visually opaque infrared filters are identified by numbers  as  follows: 87 87A 87B 87C 88A 89B When the effect of haze is to be reduced with an equal change to the gray tone rendering of all colored objects in a black-and-white print, filters that primarily absorb  ultraviolet  (UV)  radiation  are  required.  These filters have a very pale pink or yellow tint and may be identified  by  numbers  as  follows: 2A 2B 2C 2E Colorless haze or ultraviolet absorbing filters are often used to protect the front element of a lens from damage. It is much cheaper to replace a filter than it is to repair or replace a lens. The polarizing filter is another type of special- purpose filter that can be used to reduce the effects of haze. POLARIZING   FILTERS Polarizing filters look like gray neutral density filters.  However,  their  effect  becomes  apparent  when you look at the blue sky through a polarizing filter while rotating it. As you rotate the filter, the sky appears to get darker, then lighter. Polarizing filters are used in black-and-white and color  photography  for  the  following  reasons: 1.   Reduction   or   elimination   of   unwanted reflections (glare) from nonmetallic surfaces, such as glass and water 2. Exposure control, similar to ND filters 3. Reducing the effects of haze 4.  Darkening  the  blue-sky  image  in  both  black- and-white  and  color  photography 5.   Increasing color saturation in a color photograph without  altering  the  hues  of  image  colors As discussed in chapter 1 of this training manual, the term polarize refers to a property of light that cannot be seen-the direction in which light rays vibrate. Unpolarized light rays vibrate in all directions at right angles to the ray itself. A light ray is polarized when vibrations are in one direction only. Any synthetic material that polarizes light may be called a polarizer, or polarizing device. A polarizing screen is a polarizer in sheet form. There are a number of different polarizing filters. However, there are only two main types: one type fits over the camera lens and the other is designed to be used over a light source. Since they do not affect color, polarizing filters and screens may be used for both black-and-white and color photography. A polarizing device used over the camera lens may have small posts (known as indicator handles) projecting from the rim for aligning the axis of the polarizing grid. 3-8