COLOR PHOTOGRAPHY 635 



The three tissues are handled in succession in a similar manner. 



The actual operation of squeegeeing the tissues on the appropriate bromides is veiy 

 critical and the chances of spoiling the results are altogether too many. Although the 

 correct technique can be satisfactorily mastered, the serious color worker is advised 

 to resort to the use of an automatic mechanical squeegee which can be readily put 

 together without any difficulty. 



Figure 22 represents a schematic plan of the automatic squeegeer which consists of 

 a usual photowringer mounted horizontally under a table top with the top cut out and 

 beveled as shown. The two rollers should be geared to prevent slipping. 



An apron made from two pieces of matte celluloid (0.010 in. thick) and hinged 

 together with a strip of Kodatape will be found indispensable. Three aprons should 

 be provided, one for each tissue. 



The various operations leading up to a carbro print are listed as follows in a sys- 

 tematic manner: 



1. Negatives are measured and printing exposure decided upon. A test exposure 

 for the blue-green bromide (red-filter negative) can be made if desired. Information 

 thus obtained should be entered in the notebook: Exposure, lens stop, magnification, 

 type of bromide paper, developer, and time of development. 



Pencil outline Pencil outline 



for correct position for correct position 



of tissue, of bromide 



yjA^'*^ Photo iv ringer 



j^ ^-<r-Koolatape 

 f^^ hinge 



Fig. 22. — Wringer for placing bromide and carbro tissue in contact. 



2. Bromides are exposed and developed in succession (large quantity of developer 

 to avoid irregularities or a fresh moderate quantity of developer prepared in advance 

 for each bromide, making sure that the temperature remains sufficiently constant). 

 The bromide paper recommended is the Illingworth de luxe bromide, normal grade, 

 special for carbro, with grain cut in the same direction. Defender Velour Black C 

 (double weight) or N (single weight) special for carbro are also satisfactory. 



The developer recommended is Amidol compounded as follows: 



Water 1000 cc 



Sodium sulphite (dry) 25 g. 



Amidol 5 g. 



Potassium bromide (10 per cent) 4 cc. 



Develop for IH to 2 min. — temperature 68°F. 



3. Fixing of bromides should be done in plain hypo for about 15 min. (water, 

 32 oz.; hypo crystals, 4 oz.). A stop bath or an acid in the hypo should be avoided, 

 as it will affect the action of the carbro solutions unless the washing operation is carried 

 out for a very long time. 



4. The bromides should be washed in running water for 15 to 20 min. A large 

 tray and a siphon will be found very convenient for the purpose. (The Eastman 

 Automatic Tray Syphon is a good typical example.) 



