636 HANDBOOK OF PHOTOGRAPHY 



5. While the bromides are washing, the celhiloid temporary supports must be pre- 

 pared by treating the surface with waxing solution. A suitable waxing solution can be 

 made up by taking 1 g. of Autotype trichrome waxing compound, breaking it up in 

 very small pieces and letting it dissolve in 500 cc. of benzine (cleaner's benzine) or 

 in 500 cc. of benzol. One gram of pure beeswax dissolved in 500 cc. of benzine or 

 benzol will be found equally satisfactory. Benzol is to be preferred in any 

 case. This waxing solution must be prepared well in advance as the wax 

 dissolves very slowly. A small tuft of cotton is soaked with the waxing solution 

 and used to go over the entire surface of each celluloid. The evaporation of the solvent 

 wilt take place very quickly particularly if benzol is used. As soon as dry, the cellu- 

 loids will be immersed in a water bath containing a small amount of chrome alum; a 

 teaspoonful of chrome alum in 2 gal. of water is satisfactory. When immersed, the 

 celluloid should be given a lateral shaking and left to settle on the bottom of the 

 tray until ready to be used. It is generally agreed that the most convenient thickness 

 for the celluloids is 0.020 in. Thinner celluloids are difficult to handle and thicker 

 ones resist too much the bending force of the transfer paper during the drying stage. 

 Furthermore, the celluloids should be matte on one side, and this is the surface to be 

 waxed and used to carry the colored image. It will be found that the colored image 

 on a matte celluloid surface is more resistant to abrasions which readily occur when 

 superimposing the celluloids with the dried colored images in order to judge the color 

 balance. 



The weak chrome-alum bath for the celluloids is very desirable. By means of it 

 the waxed surface of the celluloid becomes completely wet, and this condition is 

 necessary to produce intimate contact between the tissue and the waxed surface, 

 thus permitting complete avoidance of air bells and any tendency to frill during hot- 

 water development. 



6. To avoid any deleterious effect from wash water, the bromides should be placed 

 at the completion of wash, in a tray containing 1000 cc. of water and 4 cc. of glacial 

 acetic acid. The tray should be rocked and moved about to insure uniform action 

 for 4 min. The three bromides can be treated in this acid bath all together. At the 

 expiration of 4 min. the bromides are washed again in running water for another 

 4 min., after which, pending the preparation of the tissues, they are placed in a tray 

 containing a small quantity of water. 



7. The carbro solution is prepared as outlined above, divided in three parts and 

 each amount located conveniently at hand. The two trays for the preliminary water 

 bath and for the carbro solution are placed next to each other. It is assumed that 

 the three tissues are already cut to size with the grain in the same direction. Since 

 the bromides have a white safe margin, the tissues can be of the same outside dimen- 

 sions as the bromides. 



8. The first celluloid apron is inserted in the automatic squeegee, as indicated in 

 Fig. 22, and opened up. A few drops of water should be sprinkled on its surface. 

 This water is necessary to decrease the adhesion of both the bromides and the tissues 

 with the celluloid apron, otherwise creases might result while passing through the 

 squeegee. This is not necessarj^ for double-weight bromide paper (Defender C) but is 

 absolutely necessary for single-weight bromide paper and for the tissue. 



9. A stop watch or a timing clock hung in a visible place is started, and the follow- 

 ing operations are carried out in accordance with the time schedule as indicated below : 



Time Schedule for Carbro Process 



. Blue tissue is placed in the tray of water, face up, and forced under. 



30 sec. Tissue turned face down ia water and forced under, holding it down with left hand; each 



corner of tissue can be folded slightly back to help uncurling. 



