22 



HOW TO PHOTOGRAPH 



the print. As a rule, all negatives should 

 be printed somewhat deeper than is required 

 in the finished picture. 



For toning the prints on ready- sensitized 

 paper, the borax, or tungstate toning baths 

 will be found the best. The formula lor 

 the borax bath is as follows : 



Solution of borax, ... 8 ounces. 

 Solution of gold chloride, . i ounce. 



The borax solution is made by dissolving i 

 ounce of borax in 80 ounces of water. 

 For the gold solution break a 15-grain tube 

 of chloride of gold \\\ a bottle, and add 15 

 ounces of water. Each ounce of water will 

 contain i grain of chloride of gold. 



For photo micrographs which look best 

 toned a black tint, the tungstate bath is 

 very suitable. The formula i? as follows : 



Chloride of gold, . . . i grain. 

 Tungstate of soda, ... 20 grains. 

 Boiling water, .... 8 ounces. 



To be used when cold. 



Many other toning formulae are used, but 

 the writer has found those given above an- 

 swer best the requirements of the photo-iiii- 

 crographer. 



Before toning, the prints must be washed, 

 either in running water or in several changes 

 of water, to remove all traces of free silver 

 nitrate. A quarter of an hour's wa>hing is 

 not loo long. The toning dish should be a 

 large shallow dish of ebonite < r porcelain, 

 capable of holding several prints side by iide 

 — not over each other in layers. Place the 

 prints in the toning bath, and gently rock 

 the dish. They will gradually change col- 

 or, and when they become of the exact col- 

 or required, remove them to a basin of 

 clean water. 



When all are toned, and when all the 

 dishes and solutions used in toning are put 

 away, to avoid all possible contamination 

 by the hyposuljihite of soda the prints are 

 transferred to the fixing bath : 



Hyposulphite of soda, . 4 ounces. 

 Water 20 " 



The fixing solution should be prepared 

 shortly before use, and one dram of liquor 



ammoniae added to each pint, to neutralize 

 the acidity of the hyposulphite. If the am- 

 monia be not added, the prints, after fixing 

 frequently appear of a sickly yellow, instead 

 of a good purple or black. 



The prints should remain in the fixing- 

 bath from ten to fifteen minutes, and the 

 dish should be rocked all the time to pre- 

 vent the prints sticking together. They are 

 next transferred to a basin or tub, and wash- 

 ed for two hours in running water. After 

 this they may be placed between sheets of 

 clean blotting-paper. When the excess of 

 water has been absorbed, they should be 

 ironed between dry blotting-paper until 

 quite dry, when a further ironing on the 

 face and back of the print with a very hot 

 box-iron will improve its appearance. If 

 the photo micrographer lave a rolling 

 press, the ironing may be omitted. 



The writer has a frame of prints treated 

 as above, which has been exposed to damp 

 and strong sunlight during three years in a 

 glass-roofed hall, yet no trace of fading can 

 be detected in any one of the prmts. 



Some subjects, such as diatoms, have a far 

 more delicate and natural appearance if 

 enamelled, either with plain collodion or 

 collodion and gelatine. Full details of this 

 simple process will be found in " Fnamel- 

 ling and Retouching" and "Silver Trint- 

 ing " published by Messrs. Piper & Car- 

 ter, The photo-micrographer who wishes 

 to excel in his art will find both works sim- 

 ply invaluable. 



Our next three or four lessons will be de- 

 voted to the consideration of " Preparing 

 Objects specially for Photo micrography. 



Lesson VIII. — Preparing Objects for 

 Photography. 

 Many microscopic objects are totally un- 

 fit for photo- micrography, as the beginner 

 will soon discover if he attempt to photo- 

 graph indiscriminately the objects in his 

 collection. It does not follow, because an 

 object looks very beautiful under the micro- 

 Slope, that it will yield even a passable pho- 

 tograph. It may look all that can be de- 

 sired on the stage of the microscope; all 

 its diffeient parts may be defined clearly 



