The silver bromide crystals for the present investigation were prepared by the dilution of the saturated solution of silver bromide in ammonia. When such crystals are exposed to light many bright points appear in the dark field of microscope, and it is known that such bright points show the existence of the photolytic silver which was formed in the crystal defects (structural imperfections). By the observation of the feature of such bright points it was known that the crystal defects are formed at the formation of the crystals in the following way; when silver bromide is precipitated from the concentrated solution it appears as the aggregates of minute crystals and it becomes afterwards apparently single crystals by recrystallization. The crystal defects are formed probably in the contact points of minute crystals in such aggregates and they grow by aggregation on the way of migration to the crystal surface. Silver bromide crystals which are apparently clear in microscope were warmed 2 hours at 60°C in the solution of gelatin containing a trace of sodium thio-sulphate, and it was known that many bright points are ormed by such treatment.
From this results it is clear that silver sulphide specks were formed by the reaction between the silver ions at the crystal defects and the thiosulphate. It was concluded that the ripening specks of silver sulphide are formed at the after-ripening by the reaction between the sulphur compounds contained in gelatin and the silver ions at the crystal defects.

View full abstract

We have observed the relation between the ripening rates and Ag ionconcentrations of the photographic emulsions.
The emulsions, which are prepared and whashed under the same conditions, are adjusted to various values of Ag ion concentration and pH, then ripened at same temperature.
The estimation of the ripening rates of emulsions at various Ag ion concentrations and pH values are led from the ripening times, which are needed to reach the certain sensitivity.
The results are as follows:
1) The chemical ripening of the emulsions is accelerateded by the increasing of Ag ion concentration and pH value (An empirical formula of this relation will be expected).
2) Ag ion concentration and pH value have remarkable influence upon the ripening rates, but not on the characteristics of the emulsions.
3) There are not essential differences between the nature of silver excess and bromine excess ripening.

View full abstract

Many studies have been done with ammonium thiosulfate to reduce the time of fixing. But some difficulties prevent even now the general use of the rapid fixing, while the necessity grows more and more in the rapid processng of film in the cinematography, television and vanadium development.
Authors have collaborated in the fundamental studies of this subject. The time of fixing is reduced in less than one third of ordinary fixer. The optimum concentration is found in the range 15-20% with ammonium thiosulf ate, about the half of sodium thiosulfate. The rapid fixer of ammonium thiosulfate has more buffer action in pH of the solution.
Ammonium thiosulfate is susceptible to the decomposition by heat. PH of the solution should be kept in the range of 4.5-6.0 One of the recommended formula is:
water 300cc
ammonium thiosulfate (60%) 100cc
sodium sulfite anhydrous 5g
glacial acetic acid 1.5cc
boric acid 3.8g
potassium alum 7.5g
water to make 500cc
pH 4.60

View full abstract

1. A new method for the synthesis of 2-methylnaphtho-[2.3]-thiazole, debromination of 2-methyl-4-bromo-naphtho-[2.3] thiazole, is described. On the preparation method of 2-methyl-naphtho-[2.3] thiazole, our method surpassed the old I. G. method, particularly on the technique and the yield.
2. On the communication of I. I. Levkoev and A. Ya. Bshkirova (C. A. 41 447), 2-thioacetamino-1-bromonaphthalene was oxidized at 5°C with alkaline K₃Fe (CN) ₆, to give bis-[1-(1-brorno-2-naphthylimino-)] ethyl disulfide and not to give 2-methyl-4-bromo-naphtho-[2.3] thiazole. But after we have studied this reaction, we gained 2-methyl-4-brorno-naphtho-[2.3] thiazole when oxidized at 25°C (yield 50%)
3. From 2-methyl-napbtho-[2.3] thiazole, we have prepared 2-methylmercapto-naphtho-[2.3] thiazole.

View full abstract

Reaction between acetic or benzoic anhydride and 1, 2-diaryl-3, 5-dioxopyrazolidine or mixture of the pyrazolidine and heterocyclic quaternary salt possessing methyl group in 2-position yielded methyl or phenylmethineoxonol and methyl or phenylmero-carbocyanine.
Methineoxonols or benzal compounds prepared from the pyrazolidine were converted to merocarbocyanine or styryl dyes by application of the quaternary salts. Unsym. carbocyanine or styryl dyes having pyridine ring underwent exchange of the ring for quinoline ring, and unsym. methineoxonol or benzal compound composed of barbituric acid underwent exchange of the acid for the pyrazolidine ring by application of alkylhalide of quinaldine analogues or the pyrazolidine. The same conversions of the parent nuclei were found to occure in some merocarbocyanine
Application of haloacetoaldehyde to the quaternary salt in glacial acetic acid yielded 2-ω-halopropenyl compound, but chloral or trichloropropenyl compounds gave no sure Brooker type trinuclei cyanine dyes while they were heated with the parent components of the dyes in pyridine containing piperidine.
The similar application of chloral to the pyrazolidine gave no trichloroethylene compounds but trinucleimethineoxonols, through refluxing in pyridine, and these dyes underwent the same exchange of nuclei for quinoline ring by heating with quinaldine methiodide as merocarbocyanines mentioned previously.
Sym. methineoxonols were obtained from the pyrazolidine and chloral by refluxing in alkali solution. Melting of carbocyanine and hydrazinodivinyl compound yielded shiny green needles, likely neocyanine. Thiocarbanilinomethylene or di thiocarbonylmethylene compound prepared from methylene base derived from the quaternary salt gave no dyes, but isocyanate or potassium cyanoxide gave some dyes when they were reacted on twice the parent components, but these products were indistinct on their constitutions.

View full abstract