THE PRODUCTION OF POSITIVES, ETC. 137 



CHAPTER VIII. 



The Production op Positives etc. 



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. 



In addition to a few dishes, a printing frame is 

 the only apparatus necessary. It 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 origi- 

 nal 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 re- 

 quired, 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 



