500 HANDBOOK OF PHOTOGRAPHY 



Water 1000.0 cc. 20 oz. 



Copper sulphate 10 . 5 g. 96 gr. 



Potassium bromide 10 . 5 g. 96 gr. 



Potassium bichromate 2 . g. 18 gr. 



Hydrochloric acid (c.p.) 10.0 g. 10 drops 



Bleach, wash well, and fix in 



Water 1000 .0 cc. 20 oz. 



Hypo 95.0 g. 2 oz. 



Wash well, and dry. Resoak for inking. 



The formula which is recommended for Kodak Royal Bromide is as follows: 



Water 1000.0 cc. 20 oz. 



Copper sulphate 10 . g. 90 gr. 



Potassium bromide 7 . g. 65 gr. 



Chromic acid . 3 g. 3 gr. 



Bleach, wash well, fix, and drj- as above. Resoak for inking. 



The writer has found both of these formulas to work well, but there are many 

 others from which to choose. 



The print should be bleached until all the characteristic black image has been 

 convert,ed to a yellowish brown strongly resembling that of an undeveloped platinum 

 print or that of a newly printed oil paper. There will be a residual image, which may 

 darken later, with exposure to light, and the second fixing recommended above is to 

 remove this image, thus preventing future deterioration of the print. 



Some workers advise giving the bleached, fixed, and washed print 5 min. in a 3 per 

 cent solution of sulphuric acid (c.p.) which tends to soften the gelatin and make it 

 easier to secure the proper relief for inking. This solution may be used warm (up to 

 110°F.), in which case the effect is still greater. A higher degree of softening of the 

 gelatin, with consequentlj' greater relief, may be obtained by using the bleacher warm 

 rather than cold. 



It is generallj^ advised to dry the bleached print and resoak before inking, some 

 workers even going so far as to state boldly that this is imperative. Such, however, is 

 by no means the case; the writer has frequently made thoroughly satisfactory bromoil 

 prints by inking immediatelj^ after the second fixing and washing. The difference 

 of opinion hinges on the fact that the gelatin, by drying, acquires a greater power of 

 differential swelling, thus increasing the scale of gradation which it is possible to secure 

 (n inking. But if high-keyed or other short-scale prints are desired, it may often be 

 preferable to swell and ink directly after the second fixing and washing, rather than to 

 drj' and resoak. This is a point for individual judgment in each case. 



Soakh}^. — Here again, no definite instructions can be given, since the degree of 

 swelling required varies with the paper, the ink, and the result which is to be obtained. 

 The temperature of the soaking water may vary from 65 to 150°F. (though it is not 

 usually safe to go above 110°F.) and the time from 5 min. to 1 hr. Generally speaking, 

 brief soaking in warm water tends to give more contrast than prolonged soaking at a 

 lower temperature, and the longer the soaking at any given temperature, the greater 

 the relief obtained with consequently greater resistance to the ink. Only experience 

 furnishes a satisfactory guide on this point, though some indication may be got from 

 feeling the clear margin of the print, which should be definitely slippery when rubbed 

 between finger and thumb; if, however, the gelatin breaks down under this treatment, 

 the water has been too hot, and the print must generally be thrown away. 



^ In connection with the matter of soaking, the following point should be noted. 



Other things being equal, the temperature of the soaking water controls the 

 degree of .swelling of the gelatin and consequently its resistance to the ink, i.e., warm 



