Salted Paper 
PLAIN or SALTED Papers.—In this process the original 
surface of the paper is practically preserved, the sensitive 
salts being more or less in the fibers of the paper, in contra- 
distinction to those processes in which they are suspended 
in an-emulsion. In all cases, however, a size should be used 
to prevent too deep penetration into the paper. V arious 
sizes may be used; starches, such as arrowroot, etc., tend to 
give brownish tones, while gelatine tends rather to more 
blueish tones. The size may be applied to the paper first, 
but it is frequently more convenient to incorporate the salts 
with it: 
Arrowroot 20 g 154 gr. 
Water 750 ccm tZ/oz: 
Rub the arrowroot into a cream with a little of the water: 
bring the remainder of the water to the boil, add the arrow- 
root cream slowly with constant stirring, and continue heat- 
ing until a translucent liquid is formed. Then add: 
Ammonium chloride l4g 107 er. 
Sodium carbonate, cryst. 23 ¢ 177 gr. 
Citric acid 7g 54 gr. 
Water 250 ccm 4 oz. 
As effervescence takes place when mixing this latter solution, 
it is advisable to make it in a fairly large beaker before add- 
ing it to the arrowroot. It is as well, though not necessary, to 
boil this solution for 5 minutes to expel the carbonic acid. 
The salted arrowroot mixture should be strained through 
fine muslin while hot. Immerse the paper in the warm solu- 
tion for 2 minutes, and hang up to dry. When nearly dry, 
again immerse for the same time, and hang up by the oppo- 
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