WITH THE MICROSCOPE. 2/3 



allow them to remain for five or ten minutes, occasionally stirring 

 them about, and relay another set. They are now ready for toning. 

 Some plunge them into water and change the water several times, 

 but in this case the backs are wetted and the unchanged nitrate or 

 chloride of silver admitted into the pores of the paper, which is not 

 advisable. Before placing the prints in the toning solution it is as 

 well to let them drain against the sides of the dish, if of small size ; 

 if larger, to at least wipe over the front and back with a glass rod, 

 so as not to pass them into the toning bath in a very wet state. 



Sometimes the printing is better if conducted in a north light, or 

 under ordinary daylight instead of sunlight, according to the character 

 of the negative. 



349. Toning ^solution. -The toning solution is prepared as 

 follows : 



8 drachms of distilled water. 



7-i- grains of chloride of gold. 



If not likely to use the solution within a moderate period, i drop 

 of hydrochloric acid is to be added to the above solution, which 

 must be kept in a stoppered bottle in the dark. 



Pour one drachm of the gold solution into a clean developing glass 

 or measure,, and add one ounce of distilled or soft water. Into 

 another clean glass vessel put half an ounce of soft water, and 

 5 grains of bicarbonate of soda. Part of the soda solution is to be 

 added to the gold gradually, stirring during the time. The solution 

 is to be tested with blue litmus paper. The addition of soda solution 

 is to be cautiously continued, until the paper is no longer reddened. 

 A drop or two more of the soda is then to be added, and the 

 neutralised solution of chloride of gold poured into a clean small 

 flat dish, and mixed with about 8 ounces of soft water. Set this 

 near to the window screened by the yellow curtain or glass. Re- 

 move the washed and drained prints from the dish, and pass them 

 into the toning solution. Here they are to be kept in motion : as 

 they appear to darken, just lift the curtain aside and note the tint 

 they have assumed by daylight, but they must not remain exposed 

 to the light any time, or the white parts will be injured. The other 

 dishes should likewise be attended to and covered over with a sheet 

 of paper to keep the light from them. When the prints appear to 

 have the desired tint, from a warm brown, through neutral tint to 

 nearly black, begin to remove the most toned, wipe them with the 

 rod and pass them into a dish of clean water. The quantity of the 

 toning solution prepared, must be in proportion to the size and 

 number of prints, about i grain of gold to one full sheet of paper. 



350. Another Toning So! nt ion.- One grain of chloride of gold, 



T 



