is  an  electrical-mechanical  device  that  can  only  provide information for which it is designed. You are responsible for  translating  this  information  into  useful  exposure data. Light  meters  are  calibrated  to  see  one  shade only-middle gray. This means the information that the meter provides, no matter how much light is falling on the subject or what the reflection characteristics are, reads the subject the same as though it were middle or neutral gray (18-percent gray). Theoretically, if you take a reflected-exposure meter reading from an 18-percent gray card and expose your film according to the reading, the result should be a picture that matches the tone of the gray card exactly; however, when you take a light meter reading of a white or black object, the light meter still reads the objects as though they were 18-percent gray. When you take a photograph that includes a gray, white, and black card, you will see how, depending on where you take the light meter readings, they affect your photograph; for example, when you take the light meter reading from the black card, the final picture reproduces the black as middle gray, and the gray and white cards as white. When you take the reflected-light meter reading from the white card, just the opposite occurs. In your final picture, the white card reproduces as middle gray, and the gray and black cards reproduce as black. This  example  demonstrates  overexposure  and underexposure. When the reading was taken from the black card, the meter raised the black tone to middle gray, and the gray card tone was also raised so it reproduced as white. Thus both the black and gray cards were  overexposed  The  opposite  occurred  when  the exposure was based on the reading from the white card. The white tone was lowered to middle gray and the gray card tone to black, resulting from underexposure. Only a light meter reading taken from the gray card allows all three cards to be imaged at their true tone. A more practical example on the way a light meter reads  18-percent  gray  is  illustrated  in  the  following example. Suppose you are going to photograph a ship alongside a pier. Bright sunlight is striking the ship from the side, causing part of the ship to be in shadow. This creates a brightness difference between the highlight area and the shadow area. Both highlight and shadow areas are equal in size and importance. When you get close to the ship and take a reflected meter reading of the  highlight  area  alone,  you  expect  the  finished photograph, like the white card in the above example, to be middle gray. When you stop down the aperture to the recommended exposure of the meter, you are also reducing the amount of exposure from the shadow area. This results in a loss of detail in the shadow area of the ship,  because  it  is  underexposed.  The  opposite  effect occurs when you take a meter reading from the shadow area. In this case, the shadow tones are raised to middle gray and have detail, but the highlights are overexposed and  completely  “washed  out.” If, however, there was an area in this scene whose tone was midway between the highlight and shadow areas, you could use it to take your light meter reading (like the gray card was used in the previous example). In this example, assume there is no tone midway between the two extremes. You can still get an accurate light meter reading of the entire ship. Since the highlight and shadow areas are of equal size, the average light meter reading you get will represent a tone that is midway  between  the  two  extremes. REFLECTED LIGHT METER READING VARIATIONS There  are  variations  of  light  meter  readings  used  to provide  accurate  light  meter  readings  of  different  types of scenes. These methods are as follows: the integrated, or average, method, the brightness range method, the darkest  object  method,  the  brightest  object  method,  the substitution  method,  and  the  bracketing  method. Integrated,  or  Average,  Method The technique of making reflected-light meter readings  from  the  camera  position  is  called  the integrated, or average, method. This method was used and explained in the examples above. This method is accurate  for  the  majority  of  photographs  taken. The  integrated,  or  average,  method  of  measuring reflected light is acceptable for scenes that consist of approximately equal portions of light and dark areas; however,   when   a   scene   is   composed   of   either predominately light or dark areas, the meter reading may not  be  accurate. The reason for these inaccurate meter readings can be more easily understood by using an example of photographing   a   checkerboard   with   alternating black-and-white squares. When the meter is held at a distance to include the entire board, the reflected light from both the black and the white squares influence the meter, so an average reading results. The light measured from this position is the integrated sum of both the white and the black squares, as though the checkerboard were one gray tone. The light meter reading from this point should  produce  an  acceptable  image. 4-23