A review of literatures related to the mechanism of the print out effect (photolytic separation of silver) in silver halides is made. Existing data of electrical properties of silver halide crystals, such as the ionic conductivity and the mobilities and the lifetimes of photoelectrons and positive holes, are summarized in Chapter I. Surface silver ions play an essential role in the dark conductivity. Mobilities of electrons and positive holes in photographic emulsion crystals seem to be different from those in large crystals. These data are compared with one another and possible explanations are given for the print out effect. In Chapter II are summarized the spatial distribution, the crystallographic orientation and the rate of separation of photolytic silver. Silver separates on the external surface as well as on the internal surface of crystals, but the mechanism of the separations may not be the same.

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In order to elucidate the mechanism of adsorption of addition agents on silver bromide grains, the measurements of electrophoresis of silver bromide sol containing addition agents were attempted. Prior to the performance of this project, several fundamental problemes were needed to make clear. The quantitative relations between the zeta-potential and the electric charges on the surface of silver bromide grains, and between the electrophoretic mobility and the zeta-potential are discussed and the approaches to the adsorption mechanism by electrophoretic measurement are explained. The apparatus and the experimental procedures are described in detail and the correction method of data for the variation of electric field, viscosity, dielectric constant etc. with any cause during experiments and the accuracy of this experiment are discussed. Application of this method to silver bromide sols showed that the effects of duration and strength of applied electric field upon electrophoretic mobility were not so significant, while the effects of temperature and addition of saccharase were appreciable. However, the effect of temperature does not change zeta-potential, while that of addition of saccharose seemed to change it. The zetapotential and electric charges of the surface of silber bromide grains at pH 6 and pAg 9 was estimated.

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Measurement of the spectral sensitivity of diazo paper, with monochromatic light that is given by combination of bright line spectrum of mercury lamp, cut-off filter and band-pass filter, is described in this paper.
On two diazo papers used, maximum sensitivity wave length is approximately 4000Å, and the range of sensitivity is about 3000-4500Å.
It has conformed to the spectral absorption characteristics of diazo materials. For 3650A radiation, given density 0.19 (at 5500Å), the absolute sensitivity of diazo papers has been 0.05-0.07 jule/cm² and 0.09-0.11 jule/cm² at 20C°.

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The color photography introduced as representing the crime scene must exactly reproduce the various colors at the scene.
Precise reproduction, however, is often difficult, and whenever the balance of the color print is lost, it must be corrected property by reducing the tones of the color.
The color reducing processes are classified into:
A. The reducing process for each layer.
a. Yellow reducing process.
b. Magenta reducing process.
c Cyan reducing process.
B. The reducing process for three layers.
The solution of the CRY-1 in the yellow reducing process.
The solution of the CRM-2 in the magenta reducing process.
The solution of the CRC-1 or CRC-3 in the Cyan reducing process.
The solution of the CRT-1 in the three layers reducing process.
The processes mentioned above are applied particularly to the color papers made in our country they may, however, be applied to the foreign products too.

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