A Review on the application for photocopying materials of light-sensitive organic compounds.

View full abstract

Experiments were performed, on cyclic and continuous desaltings of emulsion by electrodialysis using multiple ion exchange membrane cell. Constitution of cell; procedure of electrodialysis; dehydrogenation and ripening accompaning with desalting; changee of electric current, voltage and electric conductivity; and effects on characteristic curve were clarified.
By this desalting method, continuous desalting of photographic emulsion in sol state was turned to be possible, characteristic degradation of emulsion during desalting was gone, desalting time was shortened by about 20 hours and possibility of remotecontrol of desalting in a dark room was brought.

View full abstract

To make throughly continuous the all manufacturing processes of photographic emulsion, a system was necessary; in which one tank, multi stage tower, ion exchange membrane cell and pipe were combined together. There were nine ways of combinations.
By one system, in which those apparatuses were combined in one way, experiments were performed.
Raw material solutions were emulsified in a tank, 1st ripening was performed in a pipe, emulsion was mixed with gelatin in a tank, it was desalted in an ion exchange membrane cell, 2nd ripening was performed in a pipe and emulsion was mixed with additions in a tank.
By this system, the manufacturing time was shortened by about 20 hours, the characteristic flactuation of emulsion was diminished and possibility of remotecontrol of process in a dark room was brought. This system was adequate for few kind and large quantity, but not for many kind and small quantity.

View full abstract

Dynamic process of precipitation of silver iodobromide crystals, produced by running of a silver nitrate solution into a gelatin solution containing 80 mole percent of bromide and 20 mole percent of iodide, was investigated by X-ray diffractometry.
At the early stage of precipitation, only silver iodide was kept producing until the almost iodide ions were spent. At the subsquent stage, thus produced silver iodide began to dissolve graduately, producing silver iodobromide with 1-2 mole percent iodide and that saturated with iodide. Then, at the later stage, as soon as the silver iodide disappeared, the silver iodobromide with about 20 mole percent iodide medium iodide content began to appear, diminshing silver iodobromide saturated with iodide. Then, the major phase present at the end of running was the silver iodobromide with medium iodide content.
Iodide content of saturated silver iodobromide decreased with running and was about 36 mole percent as the least content. The decrease of iodide content in silver iodobromide crystals with medium iodide content was observed by running of AgNO₃ solution, and at the last stage these iodide content didn't correspond to the initial iodide ion content in the halide solution, but showed lower content.
The hexagonal silver iodide crystals, and regular and twin silver iodobromide crystals were observed by electron micrographs. The observation in electron micrographs and analysis of grain-size fractions by centrifuging at the end of running indicated that silver iodobromide with 1-2 mole percent iodide content consisted of fine regular crystals, and both the silver iodobromide saturated with iodide and the silver iodobromide with medium iodide content were twin crystals and the former was larger than the latter.
When iodide ion concentration in the halide solution was varied, the analogous processes as described above were observed.

View full abstract

The development process of five kinds of silver iodobromide photographic emulsion grains having different iodide distributions was investigated with electron microscopic observations of the grains after partial development. The emulsions were not chemically digested intentionally. The exposure was made to the thinly coated emulsion layer. The developer was of a diluted surface developer.
The results are summarised as follows;
1) Pure silver bromide emulsion grains (cubic surface).-Their edges and corners were the preferred sites for development centre formation.
2) Silver iodobromide emulsion grains with iodide-rich phase at the grain core (cubic and octahedral surface).-The development proceeded from one or two sites on their side face. The smaller grains were more rapidly developed than the larger grains, and the development centres were numerous on smaller grains.
3) Silver iodobromide emulsion grains in which iodide was most homogeneously distributed among five (cubic and octahedral surface).-There were found two kinds of grains. The one, with cubic surface, was developed in the similar fasion to pure silver bromide, and the other with octahedral surface, was little developed.
4) Silver iodobromide emulsion grains containing the silver iodide rich phase between the surface and core.-Development centres were formed on their side face (5-6 centres per one grain surface), quite different from that on pure bromide or iodobromide emulsions above mentioned.
5) Silver iodobromide grains with the iodide-rich phase on the surface.-Surface developer could not act on them (the development of them did not proceed).
It appears that the iodide incorporation of different amount and/or distribution brings different amount and/or distribution of the development centres.

View full abstract

The effects of hexachloroirridate on the photographic properties of silver halide emulsions were examined at various intensity exposures. The addition of a small amount of hexachloroirridate at the precipitation of silver halide extremely eliminates the high intensity law failure but does not influence on the characters at low intensity. When the addition of hexachloroirridate is carried out at after ripening or before coating, the elimination of high intensity law failure is not observed. It is considered that the effects of hexachloroirridate is due to positive hole trapping by trivalent irridium ion located in the silver halide crystals. The irridium (III) ion will instantaneously trap positive holes and inhibites the recombination of electrons with holes at the high intensity exposure.

View full abstract