The same principles and procedures hold when the subject to be photo- 

 graphed is "back lighted," that is, illuminated by light coming from 

 behind the object. On occasions when the back-lighted object is in- 

 accessible and no light reading can be taken of the object, satisfactory 

 results can usually be obtained by opening the camera aperture two 

 f-stops more than the general light reading indicates. 



When taking pictures of the general beach where it is desired to 

 show form or character of the beach itself, an average light reading 

 should be used. When the light meter is used as shown in Figure 2, 

 the general scene will be underexposed and it will be difficult to 

 separate the sand of the beach from the sky and water. It has been 

 found on the Atlantic coast of Maryland and Delaware that the best 

 average exposure readings for all-purpose beach photographs will be 

 obtained from the moist part of the beach just above the zone of wave 

 uprush, Figure 4. 



Use of Filters . At times it will be very difficult to separate 

 the sand, water, and sky areas in beach photographs even though the best 

 average exposure is used. This is especially true on hazy or cloudy 

 days. On sunny days, filters may be used to obtain better separation 

 of sand, sky, and water areas. The most useful filters in beach photog- 

 raphy are the K-2, G, and A filters of the Wratten scale. These filters 

 eliminate some of the blue light from the sky and thus make the sky 

 appear darker in the photograph. The filters are listed in the order 

 of their ability to filter blue light; therefore, where a small change 

 will be made by a K-2 filter, the A filter will make the sky appear 

 very dark. Since the filters function on the principle of filtering 

 blue light, they will have little effect on cloudy days when little 

 blue light is present. However they act as haze filters, or filters 

 through which greater distances can be photographed, on hazy days. 



When filters are used, some compensation must be made in exposure 

 because some of the light from the scene is absorbed by the filter. 

 This is done by assigning factors to the filters which indicate the 

 number of times that the exposure must be increased in order to com- 

 pensate for the effect of the filter. Manufacturers furnish filter 

 factors with their filters. For instance, if a filter has a factor 

 of 2, the exposure should be doubled to allow enough light through the 

 filter to properly expose the film; if the filter factor is 4, the 

 exposure should be increased four times, or two f-stops. The effect of 

 filters is most easily handled by dividing the filter factor into the 

 ASA exposure index rating and placing the resulting number in the ASA 

 scale of the light meter. This is easier than using the ASA exposure 

 number as given by the manufacturer and trying to compensate for the 

 filter by changing the f-stop or shutter speed. 



