Effects of N02 and S02 on the Degradation of Photographic Gelatin

Abstract

The degradation of photographic gelatin exposed to a mixture of two pollutant j gases, NO₂ and SO₂, was investigated by swelling measurements and steric I exclusion high performance liquid chromatography. The study, performed on one unhardened gelatin and two hardened gelatins, showed that all three are sensitive to pollutants. Two major effects were noted: the first was an increasing of the swelling of the gelatin films in deinineralized water and the second effect was a change in the steric exclusion chromatographic profile, corresponding to a shift to smaller molecular weights. Both these phenomena indicate that the pollutant gases induce hydrolysis of the gelatin macromolecules. Nevertheless, for the same exposure, the hardened gelatins are shoum to be less degraded than the unhardened one. Thus, even if it does not protect the photographic gelatin totally from attack by the pollutant gases, hardening slozos down its deterioration.     

Impact of Calcium and Methionine on the Variability of a Sulphur and Gold Sensitization on a Bromoiodide Emulsion

Abstract

Chemical sensitization uniformity requires tight batch-to-batch control of components of gelatin as well as the non-gelatin components that are present. Chemical sensitization sensitivity to variations in methionine and calcium was examined using a bromoiodide emulsion at fixed levels of sulphur and gold sensitizer. Hydrogen peroxide treatment of gelatin was used to generate a series of partially oxidized gelatins with varying methionine content. Calcium variation was examined by choosing gelatin with known natural variations in calcium and by addition of calcium salts to deionized gelatins. Sensitometric changes were seen as a function of both calcium and methionine variation. Results indicate that methionine and calcium must be carefully controlled to minimize photographic change.     

The Influence of Pre-treatment on the Properties of Photographic Gelatin

Abstract

The influence of the liming period in the manufacturing process on the chemical and photographic properties of gelatin was investigated. Three limed osseins soaked for various periods were prepared and gelatins zvere extracted from them. The impurity contents of the gelatins and the physical restraining properties decreased with prolonging liming periods. The impurity contents and physical retardance were also relative to the extraction order. The deionization treatment of gelatin decreased the impurity contents and the differences of restraining effect with extraction order. Furthermore, the fractionation of sample gelatins by use of gel permeation chromatography was applied to study the relationship to the molecular weight of impurity contents and amino acid composition, as affected by the liming period.     

Acid Ossein Gelatin

Abstract

The properties and manufacture of acid ossein gelatin are discussed with particular reference to the use of acid ossein gelatin in the photographic and allied industries.

The effect that the demineralizing process has on the properties of the gelatin extracted has been investigated with different demineralizing media. Loss of amide ammonia during the commercial demineralizing of bone has been confirmed and the rate of this toss has been studied using calcium and ammonia analyses. Different types of acid or lime processed gelatins can be distinguished also by analysis of their titration curves. From both experimental and calculated titration curve data, some correlations are found xvith gelatin amide content and isoelectric point.

A literature review is given, highlighting some of the applications found for acid ossein gelatin in the photographic industry.     

Change in the Molecular Weight Distribution of Gelatin by a High Pressure Slurry Jet

Abstract

Physical and photographic properties of gelatin depend on the molecular weight distribution of the gelatin, which it is important to control. We controlled the molecular weight distribution of gelatin by pressurizing the sample gelatin solution and jetting it at high velocity from a nozzle to a collision plate. II was found that this method teas effective in controlling the molecular weight distribution of gelatin and in preparing a gelatin which contains mainly ± and β components and few high and low molecular weight components.     

Photocharacterization of IAG Gelatins with a Monodisperse AgCI Emulsion

Abstract

The inertness degree of some IAG gelatins, the fourth series, is characterised by photographic parameters, using a pure and monodisperse AgCI emulsion. The effects of typical stabilizers to prevent the fogging action of gelatins during ageing or thermal treatment of the photosensitive material are described.     

Ionic Strength Effects in Aqueous Solutions of Gelatin and Sodium Dodecylsulphate

Abstract

The interaction between the anionic surfactant sodium dodecylsulphate and the polyampholyte gelatin in aqueous solution has been studied by viscosity and fluorescence. Three different gelatin molecular iveights, a polydisperse gelatin and two fractionated samples derived from it, have been examined at two ionic strengths. On addition of sodium dodecylsulphate SDS, the viscosity of a low molecular weight fractionated (o.) gelatin increases smoothly with SDS concentration, unlike the polydisperse (standard) and high molecular zveight (HMW) fractionated gelatins which show maxima. The viscosity increase at the maximum increases with gelatin molecular weight. On addition of 0.1 M salt, the viscosities of the gelatin-surfactant mixtures are lower than the equivalent no-salt cases. Fluorescence studies suggest that the SDS micelles adsorbed onto these various gelatins under two different ionic strengths are remarkably similar.     

On the Method for the Quantitative Separation of Nucleic Acid in Native Form from Photographic Gelatin

A method for the quantitative isolation of nucleic acid from photographic gelatin was studied. The method consists of two steps; one is hydrolysis of the gelatin backbone in which a proteolytic enzyme free from nucleases is employed and the other is adsorption chromatography with DEAF Sephadex A–50. In application lo some photographic gelatins the nucleic acid was satisfactorily isolated in about 75%, overall yield.     

The Role and the Effect of Calcium Ion Content of Photographic Gelatins on Coating Defects

The influence of the calcium ion content of some photographic gelatins on the adhesion of gelatin solutions to emulsion layers was investigated by surface tension, pH and viscosity measurements and by coating using the dip method.

Adhesion of the gelatin layers was examined in the coating process under the following conditions:

Surface tension at varying wetting agent concentrations, for gelatin solutions which contain calcium ions from 0 to 5760 ppm concentration.

Surface tension at varying gelatin concentrations.

Surface tension at varying pH values of the gelatin solutions used in the coating process.

The experimental results demonstrate that, at gelatin concentrations between 2 and 4%, the adhesion ability of a gelatin solution on a dry or wet gelatin (emulsion) layer depends on the Ca2* content of the coating solution. It is necessary to have at least 1000 ppm Ca2* concentration to guarantee a perfect adhesion and a perfect coating. Gelatin source, pH and the viscosity of the system are unimportant.     

Properties of modified gelatins at an interface

The influence of a chemical modification (hardening) on the behavior of photographic gelatins at an interface has been investigated. It has been established, using the Langmuir monolayer method, that the properties of the surface layers of a modified gelatin change at the water-air interface and the depth of modification influences the surface activity of the gelatin. The surface properties of gelatin gels were investigated by the method of wetting depending on the hardener nature and the gelatin molecular-mass composition. It has been established that the hydrophilicity of gelatin gels increases with increase in the content of α-chains and the surface of gelatin gels is additionally hydrophilized as a result of their modification. __________ Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 5, pp. 152–155, September–October, 2005.     

PA接枝明胶在黑白全色照相胶片乳剂中的应用研究

PA接枝明胶可用作沉降剂以制备浓缩感光乳剂。本文研究了其在制备黑白全色照相胶片乳剂中的作用，并与其他几种沉降剂，如：聚苯乙烯磺酸盐(F-11)、苯乙烯顺丁烯二酸酐树脂(苯丁树脂)，作了对比。试验结果表明，队胶优于其它几种沉降剂，尤其是在照相性能和与其它明胶的互容性方面。     

Lipoglycoprotein of Gelatin

Abstract

Solvent extracts were compared with the parent gelatins by means of TLC and HPLC. The photographic effects of the various protein fractions are discussed.     

Electroless deposition catalysed by gold in the photographic gelatin layer studied with positron annihilation

Abstract

The effects of free volume holes in the photographic gelatin in the electroless deposition process was studied by positron annihilation technology in this paper. The results show that, after complete activation, the average volume of the free volume holes in photographic gelatin decreased by about 0.011 nm³ which is equivalent to the volume of a gold atom. On an average basis, every free volume hole was filled by a gold atom which catalysed the electroless copper deposition. The copper grain formed in the electroless copper deposition was not filamentary in shape but a spherical stack. After electroless copper deposition was completed, the average volume of the free volume holes in the photographic gelatin decreased by about 0.020 nm³ which is equivalent to the volume of three copper atoms. Therefore, the deposition of copper in isotropic and spherical form was not hindered by free volume holes in photographic gelatin.     

Restraining Properties and Their Determination in Photographic Gelatins

Certain non-collagenous components occurring in photographic gelatins, which slow down or inhibit the physical and c emlcal ripening process are designated in the literature as restrainers.

There exists beside the “natural” restrainers other—mostly organic—compounds with similar properties, e.g., anti-foggants and emulsion stabilizers. Such substances are to be considered as “artificial” restrainers. Additions of these to gelatins may control the degree of restraining properties.

Neither the presence, not the type and the concentration of restrainer components are sufficient criteria for their activity. The reaction condillons in the investigated system are of a particular interest, especially pH.

F .Evidence by experiment is given, that at constant content of restrainers in gelatin, the degree of restraini ng is strongly dependent on pH. Or Instance, adenine loses its inhibiting properties at pH<5, but it will eract as a powerful restrainer at pH>6.5.

The activity of most restrainers increases with pH.     

Plate and Frame Filtration in Photographic Gelatin Manufacturing—Some Practical Considerations

Abstract

Gelatin filtration is a required operation in all photographic gelatin manufacturing facilities. For lime-processed bovine bone gelatin, many different filtration methods can be used, one of which is plate and frame filtration. The successful operation of plate and frame equipment depends on a good working knowledge of, and careful adherence to, good filtration practices. Careful choice of a filter medium is also important. This paper outlines many of the practical considerations gelatin manufacturers should think about when setting-up and operating plate and frame equipment, and choosing filter media.     

Ultrasonic Degradation of High Molecular Weight Components of Gelatin

Different types of gelatin were irradi ated with ultrasonic waves to investigate the process of ultrasonic degradation of gelatin. The physical characteristsics of irradiated gelatins were also studied.

The kinetics of the ultrasonic degradation of fraction H (the highest molecular weight component in the gelatin) were studied and found to be first order. The ultrasonic degradation constant k of fraction H varied with type of gelatin, concentration and quantify of gelatin solution. Values of k for lime- processed gelatins were about the same as each other, whereas the k for acid-processed gelatins were different from one another. Fraction H of the acid- processed gelatins was more degradable than those of lime-processed gelatins. There was a negative relationship between Log(k) and the concentration of the gelatin solution. Correlation of Log(k) and the quantity of sample solution was also negative. The effect of irradiation time on the physical characteristics of the gelatin was also observed. The jelly strength of the irradiated gelatins had a peak during irradiation, whereas the viscosity decreased monotonously.     

The Estimation of Restrainers

A quantitative method is described for the chromatographic separation and subsequent polarographic estimation of adenine in gelatin. The method, which has been applied to about 200 gelatins, has two important features. It is specific for adenine and enables a visual assessment of other purines and pyrimidines to be mode in the course of the procedure.

Hide gelatins have adenine contents from 10 200 ppm., but the large majority are from SO 50 ppm., ossein gelatin contains from 4–6 ppm., and pigskin between 30 and 50 ppm.     

Quantitative Determination Of Thiosulphate Ln Photographic Gelatins

An Ion exchange chromatographic method is given for the estimation of thiasulphate In gelatin. The method is suitable to replace the thioulphate af gelatins without altering their photographic behaVIour.     

Progress Medal 1959

Analysis by Ihe colour reaction with 3-methyl-2-benzothiazolone hydrazone (MOTH) has shown that dried samples of photographic gelatins contain more aldehydes than the solutions from which they are obtained. Fatty substances associated with gelatin are responsible, at least partially, for the release of aldehydes during drying.     

Physical Retardance by Modified Gelatin

Abstract

The effect of the isoionic point of gelatin on physical ripening properties was studied by the physical retardance test using modified gelatins. Carboxylic groups were blocked by the amidation reaction and amino groups were blocked by the acylation reaction.

Physical ripening speed decreased in relation to the ratio of blocked carboxylic groups and increased when the ratio of carboxylic groups increased due to acyl substitution. However we found that the final particle size of silver halide did not depend on the isoionic point of the gelatin. It was assumed that the charge shift in the gelatin molecules affected the physical ripening speed and did not affect the final particle size.