AMATEUR PHOTOGRAPHY. 



325 



for. printing. In the printing lies the ex- 

 planation of the neglect of this beautiful 

 uranium process, for, unless t._e conditions 

 are favorable, it may need many hours' ex- 

 posure to obtain a fully printed proof. The 

 sensitiveness depends on the purity of the 

 uranium nitrate. When chemically pure 

 half an hour's exposure' will suffice. Some- 

 times 8 or 9 hours have been required to 

 reach the requisite depth. On printing, a 

 faint image is given, and the proof may 

 be considered finished when the detail in 

 the shadows is clearly visible, of a pale 

 violet color. The faint impression is fully 

 bi ought out by dsvelooment, the nature of 

 the developer determining the final tone. 

 The 3 following developers are good: 

 For violet : 



Chloride of gold 1 part. 



Water 240 parts. 



For red brown : 



Ferricyanide of potassium 1 part. 



Water 48 parts. 



For black : 



Nitrate of silver 1 part. 



Distilled water 30 parts. 



Green and other colors are possible. 



Flow the developer over the print, which, 

 if correctly timed, will gain vigor in a 

 few minutes. After development, the final 

 operation is the washing, occuoving about 

 half an hour, to remove the excess salts ; 

 when the prints can be taken as finished. 

 A point insisted on in the uranium process 

 is that the paper previous to sensitizing 

 should be excluded from the light for sev- 

 eral days. 



The iron process, cyanotype, or blue pro- 

 cess, was discovered by Sir John Herschel. 

 Since it was first made known numerous 

 modifications have been introduced. It is 

 the simplest of all photographic printing 

 processes, only a single solution being re- 

 quired. A substratum can be applied if 

 desired ; but the paper prints successfully 

 with the sensitizer alone. This consists of 

 2 solutions • 



1. Iron ammonia citrate 20 parts. 



Water 100 parts. 



2. Potassium ferricyanide 16 parts. 



Water 100 parts. 



No. 2 must be mixed immediately before 

 use, as when in solution it deteriorates 

 rapidly. Make the sensitizer by taking equal 

 parts of 1 and 2, and apply to the paper with 

 a brush, takirg the precaution to go over 

 the surface in all directions. After drying, it 

 should be of a pale lemon color. A fairly 

 visible image is given on printing, but it 

 requires some experience before the cor- 

 rect printing depth can be gauged. The 



proof will not be far wrong if the printing 

 is stopped when the shadows become slight- 

 ly mealy in appearance. After printing, 

 immerse the proofs in clean water. In 

 this they gradually develop until the high 

 lights are a pure white, and the shadows 

 an intense blue. When this stage is 

 reached they may be considered as fixed, 

 and may be taken out and dried ready for 

 mounting. The developed print will be 

 changed from a blue to a violet by immer- 

 sion in a solution of caustic potash; to a 

 green by sulphuric acid. A brown can oe 

 produced by treating the violet image with 

 tannic acid. Several other methods of pro- 

 ducing blue prints have been introduced, 

 though this process forms the basis of 

 them all. — Professional and Amateur Pho- 

 tographer.. 



EASY METHOD OF ENLARGING. 



I have tried enlarging in many differ- 

 ent ways, but my best results were obtained 

 by the following method : Place the nega- 

 tive to be enlarged in a solid holder. Put 

 a wide angle lens in the camera so you 

 can get as large an image as possible with- 

 out the use of a long bellows. Then focus 

 and proceed as usual. You will obtain a 

 positive which should be developed farther 

 than a transparency. After drying place 

 in a printing frame and on this, film to film, 

 place a dry plate and expose one to 3 sec- 

 onds, according to the density of the nega- 

 tive. Print from this negative and save 

 the positive, for use in case you should 

 break your other plate. If you prefer 

 you can first make your positive and then 

 enlarge from that in the same manner. 

 When it is possible to have an enlarging 

 room you can enlarge to a greater degree. 



Always have a ground glass placed be- 

 hind the plate, to make a more even nega- 

 tive ; or place a white substance at a great- 

 er distance back to do the same thing. 



This mode is much better than enlarging 

 from a print, as it does not give a gray 

 effect nor does the print appear flat. It is 

 superior to a bromide enlargement because 

 several prints can be made instead of 

 only one at a time ; and platinum paper is 

 superior to bromide. Often a negative can 

 be improved in its printing qualities by 

 this method and it is possible to get rid 

 of many defects found in the negative. 



It is a good idea to make a positive of 

 all your best negatives in case of an acci- 

 dent. I lost one of my best negatives and 

 could never replace it because I had neg- 

 lected to make a positive. 



Clinton A. Smith, Eureka Springs, Ark. 



SNAP SHOTS. 

 Is there any coating other than blue 

 which can be used for printing on postal 



