460 HANDBOOK OF PHOTOGRAPHY 



After the prints are completely bleached, they are washed first and then rinsed in 

 three baths of 1 per cent hydrochloric acid. The prints are then washed again and 

 toned in the following solution: 



Stock Solution 



Sodium sulphide 45 g. IJ^ oz. 



Water to make 500 cc. 16 oz. 



For use, dilute 1 part stock solution with 8 parts water. 



Potassium Permanganate Sulphide Method. — Another bleach for sulphide toning 

 consists in using potassium permanganate instead of potassium ferricyanide. This 

 has one particular advantage over the ferricyanide bleach, inasmuch as any traces of 

 hypo left in the print before toning will be destroyed by the permanganate and have no 

 effect on the final image. A stain is formed when the image is bleached, but this will 

 disappear in redevelopment. Wash print well and bleach in the following solution. 



Solution A 



Potassium permanganate 2 . 5 g. 40 gr. 



Water 590 cc. 20 cc. 



Solution B 



Hydrochloric acid (c.p.) (36 per cent) 80 cc. 2^4 oz. 



Water to make 590 cc. 20 oz . 



To use take 1 part solution A, 1 part solution B, plus 6 parts water. Wash 

 well and tone in sulphide solution. 



Sulphide Redeveloping Solution 



Stock Solution 



Sodium sulphide 45 g. IJ-2 oz. 



Water to make 500 cc. 16 oz. 



For use, dilute 1 part stock solution with 8 parts water. Wash prints for 

 15 min. after toning. 



Intermediate Redevelopment Sepia Method. — The above bleach bath lends itself 

 well to control of the resulting image by means of intermediate development of the 

 print with a dilute developer after bleaching and before toning. The developer 

 acts on the bleached silver compound forming a partial black metallic silver image. 

 The remaining undeveloped silver compound, when treated with sodium sulphide in 

 the toning bath, forms silver sulphide. Thus a combined image of black metallic 

 silver and brown silver sulphide is formed, and the resulting degree of blackness 

 depends on the proportion of metallic silver that makes up the final image. Procedure 

 for this method is as follows: Bleach print according to instructions given for the 

 permanganate sulphide method. After washing well, partially develop the print in 

 a 1 to 2 dilution of the developer for blue-black tones given in the beginning of this 

 chapter. Time the length of development and then tone in the regular sulphide toner 

 given above. A few experiments will determine the length of intermediate develop- 

 ment necessary to secure the desired tone. 



The permanganate bleach will react on both the silver sulphide and silver image, 

 so that, if the desired tone is not obtained with the first trial, the toned image may be 

 bleached and retoned. Sometimes it is desirable to restore a toned print to its original 

 black state: this may be accomplished by bleaching in a permanganate bath and 

 redeveloping completely in a normal developer. 



Engraving Black from a Silver Sulphide Print. — It is possible to intensify or darken 

 sulphide-toned prints by means of lead compoimds. The lead combines with some of 

 the silver sulphide forming lead sulphide, which is black. The darkening is accom- 

 pUshed by treating the sulphide-toned print with a solution of lead acetate. Prints 



