148 DEFECTS IN NEGATIVES. 



intensity of the illumination, and magnifying power 

 of objective. The development depends on the 

 purpose for which the resulting negative is in- 

 tended, the character of the object, and the kind of 

 plate. 



It is often impossible to obtain a sufficiently dense 

 negative directly. When this is the case, the weak 

 negative should be copied in the enlarging appara- 

 tus (to be described), using a very weak illumination. 

 A positive will be obtained which on development 

 will be at all events as dense as the negative, and 

 when intensified much more so. If then another 

 copy be taken from this positive, a negative is 

 obtained, very much denser than the original nega- 

 tive. 



This simple enumeration will be sufficient to en- 

 able any intelligent person to avoid the defects 

 mentioned, or to apply the proper remedies for them. 

 For fuller information we refer our readers to any of 

 the numerous text books on this subject. 



