โ Scribed by J.I. Crabtree
No coin nor oath required. For personal study only.
By J. I. Crabtree.
REVERSED dye images may be obtained on motion picture film or any other suitable support by first dyeing the fikm with a dye that is capable of being reduced to a leuco base, and after tinting, bleaching in an ordinary acid hypo-bath, washing, and then removing the silver image by using a solvent of silver such as Farmer's reducer. Two methods of procedure are described : The first method making use of a single bath containing the dye as well as the bleaching agent, and the second, dyeing or tinting the gelatin silver image in one bath and then bleaching it in a separate bath. In both cases the film is subsequently washed and then immersed in the reducing solution.
The success of the process is largely dependent on the careful adjustment of the time of bleaching. Thorough washing before the film is placed in the reducing bath is of importance, otherwise the leuco base is mordanted to the silver ferrocyanide image and on prolonged washing is oxidized to the dye. The result is the production of a positive dye image. This difficulty, alofig with several others, is mentioned, and suggestions are given for avoiding them. Several interesting effects may he obtained by slight variations of the procedure as: (I) Production of a toned silver image with the highlights tinted by substituting for the last reducing bath either a uranium-toning bath or a dye-toning bath; (2) line effects by increasing the time of b.leaching and th'n toning as in ( I ) ; (3) unusual tinted effects by merelydyeing and bleaching and washing with slight increase of the bleaching time. The theory of the process is as follows: The dye (such as methylene blue) in the presence of hypo is locally reduced to the leuco base in the region of the silver image, and on washing, the leuco base is * Communicated by the Director. ~Communication No. 97 from the Research Laboratory, Eastman Kodak Company, and published in ti. Y.
๐ SIMILAR VOLUMES
These materials and their methods of preparation are described in a previous paper [13]. X-ray Diffraction Studies: As-prepared and calcined samples were characterized using a Rigaku Rotating Anode Goniometer. Details are provided in a previous paper [13]. Low-angle XRD scans were also obtained fro