Quantitative-analytical measurements have been made to make clear in what state are the silver ions which neutralize photoelectrons in the photolysis of silver chloride emulsion. Photolysis took place even in the presence of a large excess of chloride ion though with a low efficiency, indicating that the lattice silver ions were converted to atomic silver. The quantum yield of the photolysis approached unity in the presence of excess silver ion. A considerable fraction of excess silver ion combined with bulk gelatin and was not thought to be effective in the enhancement of the photolysis. Not all of the silver ions responsible for the enhancement of the photolysis are adsorbed on silver chloride crystals.

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Developing agents in a photographic developer have been determined by means of the titration or the absorption spectra measurement for the extract from a developer. Performance of these methods takes much time and requires a great deal of skill. It was thought desirable to investigate the use of gas chromatography as a sensitive technique for the analysis of developing agents. This paper demonstrates the rapid analysis by gas chromatography of developing agents in a photographic developer. The chromatogram represented species and concentrations of developing agents was obtained by directly injecting a small aliquot of a photographic developer. This method is far simpler than usual methods and may be recommended for control analyses of developing agents as well as for studies of chemical reactions involved in a photographic development.

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The ionic behaviors of various kinds of developing agents in aqueous solution were surveyed by the method of paper electrophoresis. The apparent values of mobility were corrected by those of H₂O₂ under the same condition.
Hydroquinone and 1-phenyl-3-pyrazolidone showed always the negative mobility, whether the solution contains Na₂SO₃ or not, in the range of pH 3-13.
Developing agents having -NH₂ group showed in the solution not containing Na₂SO₃, the positive mobility in the range of pH less than 9, and the negative mobility in pH greater than 11. About 9-11 were the isoelectric points. In the solution containing Na₂SO₃, these points were located in the lower range of pH.

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Studies for improving a stability of light sensitive material has led to find the new system which has much higher stability during storage.
In the new system, a light sensitive diazo compound and a coupling component are finely powdered and dispersed in a binder. Besides these chemicals the finely powdered substance which melts easily upon heating is also dispersed in the binder.
In some cases, the compound which can generate an alkali on heating is incoporated in a form of fine particle to promote a coupling reaction.
The new material can be used entirely in the same manner as the conventional diazo type materials in light exposure and in heat development. Furthermore reversal and thermographic processes can be well applied to the new material for obtaining a reproduction.

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