THE PRODUCTION OF POSITIVES. 



UNIVERSITY 



CHAPTER 



THE PRODUCTION OP POSITIVES, 



Silver printing by contact calls for little comment, 

 as the process is much simplified by the sale of 

 sensitised albuminised paper possessing the great ad- 

 vantage of keeping for many months without dete- 

 rioration. 



A few dishes, and a printing frame are the 

 only apparatus necessary. The latter consists of a 

 shallow wooden box, the bottom of which is formed 

 of a sheet of thick plate glass. The negative is 

 placed on the glass, a sheet of sensitised paper over 

 its prepared side, then a thick cloth pad, and over 

 all a hinged back. Two cross bars having springs 

 attached to them, are hinged to one side of the box, 

 and when pressed down on the hinged back, can be 

 fastened in position by clips fixed on the opposite 

 side. The process may be watched by unfastening 

 one of the cross bars and lifting that side of the 

 sensitised paper ; when released it will fall back to 

 its original position on the negative. 



The character of the resulting picture can be 

 modified to a great extent by a proper consideration 

 of the kind of light required, and very artistic effects 

 may be produced by shading under-exposed portions 

 of the negative. An intense diffused light will be 

 required for a dense negative, while one possessing 



