SPECIAL PRINTING PROCESSES 477 



Nontransfer Method. — In this method, the bromide print and its adhering carbon 

 tissue are treated exactly as described for stripping and development in carbon work. 

 If, however, the work has been properly done, the carbon tissue will strip and develop 

 somewhat more freely than in carbon work and will be a trifle more delicate and liable 

 to injury. Therefore this part of the work should be carried out rather carefully, the 

 worker feeling his way more slowly and gradually than in carbon. 



Large Prints. — Carbon tissue larger than about 11 by 14 in. is not easy to handle 

 by the above method, and in this case the sensitizing and control baths may be com- 

 bined in the following proportions: 



Water 15 oz. 



Sensitizer 16 oz. 



Stock control bath '4 oz. 



Sensitize for 2J^ min., then proceed with squeegeeing and subsequent operations 

 in the usual manner. This combined bath should be mixed immediately before use, 

 and should not be kept over, as it decomposes in the course of a few hours, even with- 

 out use. 



Hard Water. — In localities where the tap water contains a large proportion of dis- 

 solved calcium or magnesium salts, it will probably be found that the carbro prints show 

 a decided erosion or breaking down in the high lights. It is sometimes recommended, 

 in order to avoid this trouble, that the bromide prints receive 5 min. in a 3 per cent 

 hydrochloric acid bath, followed by not less than 10 min. or more than 40 min. washing 

 in running water, this treatment to follow the washing after fixing or to precede the 

 soaking for squeegeeing. The writer has not found this technique to be invariably 

 successful, and he prefers, where the local water is hard, to process the bromide prints 

 and the carbon tissue throughout, up to the point of developing the carbro, in distilled 

 water. 



When distilled water is used, or where the local water is exceptionally soft, it will 

 probably be necessarj^ either to shorten the time in the control bath or to use this 

 bath more dilute; the latter method is preferable since it can be more accurately 

 adjusted. Thus the writer finds that, when processing w^th distilled water throughout, 

 he obtains normal results with 20 sec. in a bath made up of 



Water 1000 . cc. 64 oz. 



Stock solution 15.0 cc. 1 oz. 



Obviously, this is a matter which each worker must adjust for himself. 



Safe Edge. — In carbro, as in carbon, it is desirable to have a freshly cut edge on the 

 carbon tissue, and it is imperative to use a safe edge. This safe edge may be attained 

 by simply allowing the carbon tissue to extend over the print by 3^2 ^^- or so all around, 

 in which case waxed paper should be placed under the bromide print, before squee- 

 geeing, so that the carbon tissue will not be squeegeed to the glass at any point. The 

 writer feels it preferable, however, to make the bromide on a large sheet of paper, 

 masking the paper so as to get 1 in. or so of clear margin all around the print. The 

 tissue should then be cut to such a size that its edge comes between the printed 

 portion and the edge of the bromide paper. Thus, for an 8 by 10-in. carbro, he would 

 use 11- by 14-in. paper and cut the carbon tissue to about 9 by 11 in. 



After treatment of Bromide Print. — The effect of the sensitizer on the silver image 

 is to bleach it out, precisely as in the case of toning by means of bleaching and sul- 

 phiding. The carbro print having been developed, it follows that there are several 

 ways in which the bromide print may be treated. 



If the transfer method is used, the bromide print, after thorough washing, may 

 be redeveloped in any ordinary developer and used for the production of other carbros, 

 exactly as at first. It should be noted, though, that this bleaching and redeveloping 



