If you hold the meter so close to one of the white squares that the black squares have no effect on the meter reading, the reading is higher than the integrated reading and the meter indicates that the scene requires less exposure. The same principle applies when a reading is taken close to a black square. The reading indicates that the scene requires more exposure. Each of the meter readings is a measurement of 18-percent gray. You can apply this checkerboard example when you photograph scenes that are predominately light or dark Compensation  is  required  to  expose  such  scenes correctly. As a general guide, you should double the indicated exposure when the light measurement is taken from a predominately light scene and detail is desired in the shadows. When you take a light meter reading from a predominately dark scene and detail is desired in the highlight areas, you should reduce the exposure by one half. Brightness Range Method This method requires you to take two readings from the scene: one from the highlight area where detail is desired and another from the shadow area where detail is desired. You then base your exposure on a point midway between the two readings. The  brightness  range  method  of  determining exposures for most scenes usually provides detail in both the highlight and the shadow areas. An exception to this is when the exposure latitude of a film is not capable of recording the brightness range of the scene. This can occur with scenes that have extremely great brightness ranges. A scene brightness range is the difference between the brightest and the darkest areas of a scene and is usually expressed as a ratio. The average brightness range of a normal scene is 160:1. Films used for pictorial work are capable of reproducing this  brightness  range.  When  the  scene  exceeds  a brightness range of 160:1, you must compromise the exposure. This compromise can be as follows: Underexpose and sacrifice shadow detail to retain  highlight  detail. Overexpose and sacrifice highlight detail to retain  shadow  detail. Do not compensate and expose for the midtones and  sacrifice  both  highlight  detail  and  shadow detail. Darkest Object Method The   darkest   object   method   of   determining exposures is actually a variation of the brightness range method. When you desire detail in the shadow area or darkest object within the scene, you take the light meter reading   from   this   area.   This   method   actually overexposes the film overall, causing the highlight areas of  the  scene  to  be  greatly  overexposed.  This overexposure occurs because the light meter averages the light reflected from the shadow area and indicates an exposure to produce middle gray. When a great amount of detail is not needed in the shadow area and you want to expose the overall scene normally, you can take your light meter reading from the darkest object or shadow area and stop down two f/stops. This method provides a good overall film exposure of the shadows, midtones,  and  highlights. Brightest  Object  Method Another variation of the brightness range method is the brightest object method. The brightest object method of calculating exposures is used when a highlight area within a scene is the only area within the scene from which you can take a light meter reading. This method can also be used when you want to record detail in the highlight area In both situations, you take only one light meter reading of an important highlight area. When you do not want the highlight to record as a middle-gray tone and desire a good overall exposure of the scene, you simply open up two or three f/stops from the indicated exposure. When you need maximum detail in the highlight area, you can use the reading that the light meter provides. This records the highlight area as medium gray. This method underexposes the film in other areas of the scene that reflect less light. Substitution Method With the substitution method, you replace an object within the scene with an object, such as a gray card. You then take a reflected-light meter reading from this object. You use this method when the other methods of determining exposure are not possible. Such situations may be caused by excessive distance between the light meter and the scene, barriers in front of the scene, or the size of the scene makes it impossible to get an accurate light meter reading. The substitution method is often used in studio situations where objects may be too small to  obtain  an  accurate  light  meter  reading. You should select substitution objects that match the light reflectance quality of the object in the scene; for 4-24