As the last part of the theme the following items are reviewed; the behaviors of gelatin (1) on the exposure of a sensitive layer to light;(i) filter effect (ii) halogen acceptance (iii) protective action against latent image regression, (2) during processing, and (3) during storage of sensitive materials and processed matters.

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The influence of the presence of bromide ion upon the iodine-azide reaction of thiourea was investigated. Potassium bromide was employed as an agent to provide bromide ion. The pH of the mixture of thiourea and potassium bromide was variously changed. The difference between the solutions which were not allowed to stand after their preparations and those which were allowed for a certain time was also investigated. No effect of presence of bromide ion upon the iodine-azide reaction was concluded.

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The influence of the presence of both silver ion and bromide ion upon the iodine-azide reaction of thiourea was investigated. Silver nitrate and potassium bromide were respectively employed as an agent to provide silver ion or bromide ion. The pH of the mixture of thiourea, silver nitrate, and potassium bromide was variously changed. The difference between the solutions which were not allowed to stand after their preparation and those which were allowed for a certain time was also investigated. The results showed that the influence of the presence of both ions on the iodineazide reaction was similar, but not completely, to that of the presence of silver ion.

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By using Picinbono-Savelli's model, the size and density of developed silver grains were estimated from the observed values of photographic density and Selwyn granularity.
In Fuji Process plate which has been exposed to 50KV electrons, the density of silver grains is nearly equal to the density of incident electrons. Therefore, it is concluded that the graininess of photographic image is due to mainly the inhomogeneity of the density of incident electrons. Through the reexamination of Leisegang's data, it is inferred that the above conclusion may be correct also for almost photographic plates which have been exposed to electrons.

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The Houston model-22 has been set up in the Engineering Faculty of Chiba University by. Dr. Professor Genda's investigation with the expenses of the import machinery for -scientific studies on the Department of Education.
We will show about its function and technique for management, on this report.
The machine is important connection with Televising Film for the studies of. Color Television, which has given a great development to “Studies of Color Film for Color Television ” by Genda and Kubo.

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In a previous paper, the photographic sensitivities of the emulsions with silver salts of fatty acids have been discussed.
In this paper, the emulsions with silver salts of aromatic carboxylic acids such as benzoate, salicylate and cinnamate were prepared and their photographic properties were studied by the similar method in the previous paper.
These emulsions were exposed to light and gamma rays and then were developed at 16±0.5°C in 1.5 minutes by the acidic developers having redox potential lower than +0.543 Eh volt.
The results are summarized as follows:
1) The light sensitivities of these emulsions are about one or two hundred times lower than those of the silver chloride emulsions, but are comparative with those of silver salts of fatty acids.
2) It is shown that active gelatin has more effective than inert gelatin for obtaining the higher sensitivity and contrast.
3) The spectral sensitivities of the emulsions exist in the range of wavelength from 4405Å or 4073A to ultraviolet region. The range is almost the same as in the emulsion with silver salts of fatty acids.
4) In the gamma-ray radiation, the emulsions with silver salts of organic (aromatic, aliphatic) acids have sensitivity to dose about 1-5×10⁶ roentgen.

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