REPRODUCTION OF ILLUSTRATIONS 



This negative is now laid upon a copper or zinc plate 

 and treated in the same manner as the zinc etching just 

 described. As the minute rulings of the screen were 

 filled with a dark pigment that prevented the passage 

 of light, it is obvious that the layer of sensitized film 

 will be acted upon in minute checks representing the 

 meshes of the screen. When this has been acted upon 

 for a sufficient length of time, the copper plate is re- 

 moved, inked, developed, and washed, this washing 

 removing all the particles of the sensitized coating not 

 hardened by the light. The plate is then dried, heated, 

 and subjected to an acid bath which "bites" away the 

 intermediate surface of copper about the dots. The 

 plate thus finished is mounted type-high, and may be 

 inked and printed in the same manner as ordinary type. 



Of course, in the actual practice of making fine half- 

 tones the process is somewhat more complicated, al- 

 though not differing in principle. For example, the 

 engraver, wishing to produce lighter or darker effects, 

 "stops out "certain portions, and "bites "others longer, 

 to get the desired effect. But these are details, and this 

 process has made it possible for an ordinary workman, 

 having neither artistic taste nor any great degree of 

 mechanical skill, to produce in a few hours, or even 

 minutes, an engraving which gives a more faithful and 

 natural reproduction of drawings or objects than is 

 possible by the most skilful wood-engraver after weeks 

 of hard labor. Furthermore, any number of such en- 

 gravings may be made from the same negative. 



The result of the discovery of this simple process 

 with its wonderful effects was the finishing blow to 



VOL. VIII. 14 [ 2O9 ] 



