CHAPTER XYIII. 

 GELATINE CHLORIDE PAPER. 



BY some manufacturers paper is coated with emulsion of 

 gelatine chloride (argentic) with a certain excess of argentic 

 organic salt, and paper so prepared is used for " printing-out " 

 in a manner very similar to albumen paper. (The term " print- 

 ing-out" is used to signify a process wherein the image is 

 revealed by the action of light alone, in contradistinction to 

 the term " printing by development," where after light-action 

 the image is wholly invisible or only faint, and development is 

 required to bring the image to its full vigor.) 



The practice of printing the gelatine-chloride paper is pre- 

 cisely similar to the practice with albumen paper. A few 

 details of difference may be noted as to the properties of the 

 papers. The gelatine-chloride paper gives much more contrast 

 than ordinary albumenized paper, so where we have thin weak 

 negatives the former offers a great advantage. The gelatine 

 paper seems, as a rule, to lose as much depth in operations 

 following printing, but seems to require a considerably larger 

 quantity of gold chloride to produce the toning effect. The 

 printing of the gelatine paper is usually more rapid than that 

 of the albumen paper. 



After printing with Dr. Liesegang's paper no washing is 

 required, but the prints are at once toned in a bath made thus : 



Water 24 ounces 



Sodic hyposulphite 6 ounces 



Ammonic sulpho-cyanide 1 ounce 



Saturated aqueous solution of potash alum 2 ounces 



Dissolve, and place in the solution some scraps of gelatine- 

 chloride paper for about 24 hours. Filter, then add : 



Water , ... 6 ounces 



Auric terchloride 15 grains 



Ammonic chloride 30 grains 



