638 HANDBOOK OF PHOTOGRAPHY 



with firm hand to expel the moisture from between the tissue and the celluloid. Eight 

 or ten strokes will be sufficient and the celluloid support with its adherent tissue 

 placed under moderate pressure (four pieces of plate glass) between blotting paper 

 until the next celluloid and tissue are ready to take its place. 



24 min. The next celluloid support is removed from the alum bath, handled in the same manner 



as the first one, and placed on the piece of plate glass. The red tissue is now stripped 

 from its bromide, dipped in water, squeegeed and placed under pressure with its 

 celluloid in place of the blue sandwich, which is now laid out in the open, after care- 

 fully wiping off any trace of moisture along the edge of the tissue. 



30 min. The third celluloid and yellow tissues are handled in the same manner as the two pre- 



vious ones. Hot-water bath at about 105°F. is now prepared. 



36 min. The third celluloid with its yellow tissue is removed from under pressure and laid out in 



the open. 

 The blue tissue on its celluloid support is now placed in the hot-water bath and after 

 about 13-2 min. the paper backing is stripped off by pulling gently from two opposite 

 corners. 

 The blue image is now fidly developed by lateral shaking of the celluloid under water. 

 This operation will take about 2 min. to fully develop (a condition which can be 

 readily judged). 

 The celluloid with its blue image is passed in cold water and rinsed until no appreciable 

 amount of blue color runs off, after which it is hung up to dry. 



42 rain. The red image is now developed in hot water, rinsed in cold water, and hung up to dry. 



48 min. The yellow image is finally developed in hot water, rinsed in cold water, and 



put to dry. 

 The three colored images, when dry, are to be assembled together in correct register 

 upon a final paper support. This assembling operation can be carried out in two 

 ways: bj^ single- and by double-transfer method. 



Single Transfer. — Decision as to which method is to be followed must be made 

 before printing the bromides because with the single-transfer method the bromides 

 must be printed from reversed negatives, otherwise the final image will be laterally 

 reversed with respect to the original subject. 



With the single-transfer method the yellow image must be transferred first to the 

 final paper, then follows the magenta, and finally the blue-green image uppermost. 



For final support a fixed-out bromide paper or the regular transfer paper which is 

 available commercially could be used. 



The final paper should be soaked in cold water for at least V^ hr., and, when ready 

 to make the first transfer, the celluloid carrying the yellow image should be also 

 immersed in the cold water for a few minutes and the two lifted out together, avoiding 

 air bells between them. A moderate squeegeeing with the flat squeegee is desirable, 

 after which the sandwich can be hung up to dr3^ When completely dry, the celluloid 

 will automatically detach itself leaving the yellow image on the final paper. A slight 

 amount of wax always transfers with the image, and it must be carefully removed 

 before proceeding with the next transfer. This is best done by going over the yellow 

 image with a tuft of cotton dipped in rectified spirit of turpentine. The turpentine is 

 allowed to remain for a minute or so. Another tuft of cotton is now soaked in benzine 

 and applied gently to the j^ellow image, after which the benzine and turpentine 

 together are cleaned off with a piece of dry cheesecloth. The cleaning of the print by 

 means of benzine should be repeated three or four times and each time cleaned off with 

 cheesecloth. Finally the surface of the print should be gone over with a large piece 

 of clean cotton flannel. 



The final support with its yellow image should now be placed again in cold water 

 or better still in a traj- containing a weak solution of gelatin (1 oz. of Nelson's gelatin 

 No. 1 dissolved in 32 oz. of water). The gelatin solution is highly desirable to permit 

 intimate adhesions between the yellow image and the magenta image which has to 

 follow. The celluloid bearing the magenta image is also placed in cold water and 

 finally passed into the gelatin solution and placed in approximate registration with the 



