THE PEODUCTION OP POSITIVES. 161 



Many artists prefer the delicate tone of the ordin- 

 ary silver print to that produced on a gelatino- 

 bromide surface. All that is then necessary is the pro- 

 duction of a positive on paper, if a negative by 

 daylight ; or on glass, if one by lamplight is re- 

 quired. This method has the advantage of allowing 

 the production of any degree of density in the several 

 proofs by subsequent intensification. 



By varying the processes, immense power is given 

 the operator, and no matter what the character and 

 condition of a photo-micrographic negative, it is 

 quite possible to change it completely without alter- 

 ing the essentials of the structure depicted on it, 

 thus rendering possible the production of a print 

 from what would otherwise bo considered a useless 

 negative. 



It might be objected that the whole process, from 

 the first production of a negative with the micros- 

 cope to the finished print, was too tedious to be 

 practicable. This is by no means the case, because 

 the production of a negative only takes one hour, and 

 several can be produced together with a very little 

 increased expenditure of time. The subsequent 

 washing is not considered, as it requires no special 

 attention. The printing by camera, contact, or 

 enlarging, takes about half an hour, and the 

 finishing about another half hour, therefore from 

 beginning to end the actual time consumed is about 

 two hours. 



