104 



PHOTO-TELEGRAPHY 



image is made visible by staining up the print in 

 an aniline dye solution, the glue taking up the 

 colour readily. 



Photo -engravers know that in making a half- 

 tone photograph, even with the cross screen, a good 

 deal of the detail is lost, and this is only natural 

 when we consider that, instead of a solid black or 

 grey, we have only dots on a white ground. In 



FIG. 48. Finish of the St. Leger, wired by the Telectrograph. 



making a single -line picture a great deal more is 

 lost, and thus before making the screen negative 

 the original has to be considerably retouched, the 

 contours have to be very clearly defined and accen- 

 tuated, and the paler tints have to be made con- 

 siderably bolder, as these lose the most in the 

 reproduction. The solid blacks, on the other hand, 

 require to be made grey, so that the lines repre- 

 senting them in the half -tone picture are not too 

 wide and close together. 



