324 



RECREATION. 



when fine detail is not desired, a rough 

 drawing paper will give artistic and 

 sketchy impressions. 



Many organic substances have, at dif- 

 ferent times, been employed as sizes for 

 photographic paper, those finding most 

 favor being gum, gelatine, albumen and 

 arrowroot. Each of these will answer as a 

 substratum, the character of the print be- 

 ing controlled by the substance used. Gum 

 and gelatine give strong and vigorous 

 images of a brown or rich sepia ; arrow- 

 root and albumen softer and more delicate 

 prints. They can all be applied to the 

 paper by simply brushing them over the 

 surface, care being taken that only one 

 side is coated. Gelatine and arrowroot 

 may, if desired, be made by means of hot 

 water into a thin paste, poured into a dish, 

 and the paper floated on the surface. A 

 more even coating is secured by floating 

 the paper in that manner, as when applied 

 with a brush the sizing is apt to dry 

 streaky. The coated paper should be hung 

 up to dry, when it can be kept any length 

 of time. 



Any sensitive salt may be utilized as a 

 sensitizer,. With albumen and gelatine, 

 silver chloride is most commonly employed 

 in combination with an organic silver salt, 

 such as a citrate or tartrate. Bichromate 

 of potassium and gum are combined to 

 form the image in the "Bi-gum"^ process. 

 The sensitizer is applied in precisely the 

 same manner as the substratum ; that is, 

 with a brush, or by floating on a solution 

 of the salt. This, of course, must be done 

 in a non-actinic light, the paper, when dry, 

 being stored in a dark place. In general, 

 the sensitized papers do not keep well, it 

 being advisable to use them within a few 

 days of their preparation. There are many 

 processes and different sensitive salts. Sil- 

 ver, uranium and iron processes are typi- 

 cal. The substratum for the silver process 

 is: 



Gelatine 25 grains. 



Ammonium chloride 15 grains. 



Water 2 ounces. 



Soak the gelatine in the cold water for 

 an hour; add the ammonium chloride, and 

 place the vessel containing them in hot 

 water until the gelatine dissolves. When 

 ready apply the solution to the paper, post 

 card, or whatever surface is to be sized. 



For silk or linen, the following is pre- 

 ferable : 



Arrowroot 4 grains. 



Ammonium chloride 4 grains. 



Boiling water i l A ounces. 



Wash the material first, then iron and 

 immerse in the solution for 5 _ minutes ; 

 t^ke out, and when dry, iron again. 



The sensitizer for the gelatine substra- 

 tum is: 



Silver nitrate 60 grains. 



Citric acid 15 grains. 



Distilled water 1 ounce. 



For the arrowroot, a weaker solution is 

 employed, consisting of: 



Silver nitrate 20 grains. 



Water 1 ounce. 



These proportions of ammonium chloride 

 must be strictly adhered to, otherwise the 

 sensitiveness of the paper will be reduced. 

 The silver chloride is added to give body 

 and depth to the print, and to aid the ton- 

 ing. For silk and linen, the printing should 

 be carried much beyond the average depth 

 for prints. In sensitizing, float the paper on 

 the solutions 2 to 3 minutes. Should the 

 image on printing be weak, and lacking in 

 depth, the nitrate of silver can be increased 

 in strength to 80 or 100 grains an ounce. 

 If the prints are dull and have a sunken 

 appearance, the floating may be reduced 

 to one minute. Tone as with P. O. P. 

 The prints tone readily, and may be carried 

 through brown sepia, a rich purple to a 

 blue black. One of the best toning baths 

 is : 



Gold chloride 1 grain. 



Acetate of soda 30 grains. 



Water 8 ounces. 



The above must be mixed at least 24 

 hours before use. For immediate use. the 

 bicarbonate bath is excellent, giving a blue 

 black tone. 



Chloride of gold 1 grain. 



Bicarbonate of soda 4 grains. 



Water 8 ounces. 



This bath does not keep, and should be 

 made only as wanted. When the toning 

 proceeds too rapidly, as is often the case 

 with these papers, slow down the bath by 

 dilution with water. Fix and wash the 

 same as with P. O. P. 



The uranium process is one of the most 

 interesting of photographic printing meth- 

 ods. The prints are unlike those made by 

 the usual methods, being comparable to 

 wash drawings or water-color paintings. 

 The manipulation is even more simple than 

 that of the silver process, only 2 solutions 

 being needed, the sensitizer and the de- 

 veloper. Sized paper can not be employed 

 with success, the plain drawing paper being 

 sensitized with 



Uranium nitrate 240 grains. 



Water 16 ounces. 



This is applied, as before described, 

 either with a brush or by floating on the 

 solution. When dry, the paper is ready 



