Recently the rapid strides were made in all fields of the photographic chemistry, especially in the field of addition agents for photographic emulsions.
Among them, the antiplumming agents and blue-black toning agents found in patents from 1950 to 1960 are reviewed.

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The influence of alkyl homologues of eight classes of compounds on the color of the developed silver image was investigated with a liquid silver chloride emulsion developed by a dilute phenidone-hydroquinone developer. Each agent was added in various amounts to samples of the emulsion prior to development. Development was stopped and the emulsion was fixed by adding first a small portion of a stop solution and then a fixer. Spectrophotometric density curves of the silver dispersions were obtained. The effects of alkyl homologues on the “color ratio”(cf. reference 1 and 4) of developed silver are shown in the figures in this paper.
The experimental results indicate that the effects of alkyl groups on the color of developed silver are closely related with the properties of the compounds such as adsorbability on the surface of silver chloride or solubility in the liquid photographic emulsion. In some cases, however, it can not be explained sufficiently on the basis of only such properties of the compounds.

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The mechanism of desensitization of panchromatic emulsions by cyan couplers have been investigated. The spectral desensitization in emulsion is absorption-desorption competing reaction. In the case of active reaction, it was determined that they consist of two processes, namely, the first step is the fast desorption of the j -aggregate of the sensitizing dyes and the second is the desorption of H, D-aggregate or monomer from the surface of the AgBr grains. We determined the rate constants of these desorptions for various coupler concentrations.
By the data of electrical conductance, surface activity, viscosity and the rate constants, it was confirmed that the factors act as desorptive force are due to the presence of coupler, gelatin-coupler micelle or coupler micelle. The desorption of sensitizing dyes in emulsion depends not on the exchange-adsorption between the coupler and the dye to Ag X, but on the forces acting between the coupler and the micelle. They are complex reaction involving chemical affinity such as electrostatic or van der Waales forces or solubilizing power of these micelles.

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Some characteristics of Electrophotographic Papers such as Electrofax papers and polyvinyl-carbazole (PVK) papers have been investigated. Relationships between surface potential and toner density after development are disscussed, as well as relation between exposure and surface potential. Surface potential characteristic curves obtained for Electrofax papers are in good agreement with those expected by the theory.
In the case of PVK however, the time potential decay curves are not represented by expotential functions, and time constants are found to be dependent on the surface potential.
Bunsen-Roscoe reciprocity law has not been found to be valid for PVK in high intensity region.

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In a previous paper part III, we reported that the polarizing film of borated polyvinyl alcohol (PVA-B) was much superior to that of polyvinyl alcohol (PVA) in heat and moisture resistance property.
But we often experience that PVA-B film is torn off easily in the process of wet streching. This report discusses the wet streching condition of PVA-B film to prevent above defects, and considers the bonding state between PVA and boric acid.
Experimental discussion has brought the wet streching condition to light, that the high concentration of boric acid must be contained in streching bath and held in high temperature suitable for its concentration. About the bonding state, we have proposed net working structure as well as in dry state, bonding with boric acid on the surface of PVA film or its micell, and movement of bond by wet streching.

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It is the purpose of this paper to obtain the marginal reduction magnification and the letter capacity of photographic materials for duplicating use. The letter capacity is defined bymaximum accomodation number of image of reduced letter in specific area of photographic material, when the image quality of the letter is just acceptable. The marginal reduction magnification for 8 point type was 34 with Fuji Minicopy film, and was 26 with Fuji Neopan F film developed by Sease 3 developer. In this case, the letter capacity in the area of 36×24 mm was about 135, 000 with the former film, and was about 79, 000 with the later film. The image quality of the letter was evaluated by psychological scale of five step. Relation of the marginal reduction magnification to the spatial frequency for the specific gain of response function was obtained.

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