Photographic Procedure for Complex Chart Visual Interpretation Records*

Comparison of complicated chart records is not an easy task, even if great trouble is taken to produce transparent film copies dye-toned to contrasting colours. The lines may cross and re-cross so frequently that the sequence of events is difficult to see. In suchcases superimposition of above-the-line and below-the-line silhouettes is helpful, since it permits both the sign and the magnitude of the error at any point to be readily seen. Photographic procedures are described for making such silhouettes from commercially available materials.     

The Quantum Sensitivity of Photographic Emulsion Grains

A method is described of obtaining the response curves of individual size classes of a photographic emulsion in which the exposure scale is expressed in absorbed quanta per grain. No assumptions of any significance are involved. The method is applied to the derivation of sensitivity characteristics of grains in modern emulsions of high speed for their average grain size, and to other emulsions not chemically-sensitized to such a high level. It is found that the sensitivity spread among grains of a single size may vary from about 1.0 to 2.0 log units, depending on the emulsion, but does not vary greatly for grains of different size in the same emulsion. The numbers of absorbed quanta involved are such that the greater part of this spread must be attributed to the fact that within a single size class grains differ widely in the numbers of quanta which they must absorb in order to be rendered developable; quantum fluctuations make only a small contribution to the spread in exposures over which grains become developable. Grains of the highest sensitivity encountered become developable after absorption of about 4 quanta, which suggests that a latent image of minimum developable size consists of 4 silver atoms.     

Behaviour of Thiosulphate in Electrodialysis in the Presence of Photographic Gelatin

Electrodialysis of a 10 per cent solution of gelatin containing 30 /M of thiosulphate labelled 3,S in the outer sulphur atom was carried out with a brentzinger apparatus. Forty-five per cent of the radioactivity appeared in the anodic liquid, thirty per cent in the cathodic and the remaining twenty-five per cent in the gelatin solution. The validity of these results is discussed also in relation to other experiments carried out with ,SS labelled sulphate and :aP labelled phosphate.     

A Comparison of the Crystallographic and Photographic Properties of Bromo-Iodide Emulsion Grains

A range of commercial bromo-iodide X-ray emulsions has been examined by an X-ray diffraction line-broadening technique. The emulsion grains of this type are in general very imperfect and large structural differences exist between the fifteen materials examined. There was no correlation between these crystallographic differences and selected photographic properties, thought likely to be dependent upon structure.     

Photographic Processing with One-Time Use of Solutions

Most industrial processing machines, in the motion-picture laboratories, as well as in the large photofinishing stations, tend to be very large and to contain hundreds of gallons of solutions. This tendency seems to be right when considering the high chemical inertia resulting from such big volumes, but its corollary is the progressive and unrelenting chemical evolution of the solutions. So as to avoid this an artificial equilibrium is maintained by continuous replenishing with a suitably compounded solution, and an overflow of used liquid. This method is not very economical, and requires a rigorous chemical control and leads to tank formulae which are not necessarily the most suitable for the emulsion to be processed.

One-time use of solutions, on the contrary, allows the chemical equilibrium to be established by the initial formula itself, which can, therefore, be exactly adapted to the emulsion considered. This system, which makes chemical control unnecessary, is very economical provided that the overflowing solution volume is entirely exhausted, which is true only for a high ratio of processed surface to solution volume.     

The Adsorption of Gelatin to Developed Silver and the Role of Gelatin in Development

The adsorption of gelatin to developed silver is demonstrated and semi-log isotherms are constructed at two temperatures in the presence and absence of developer components. Analysis of the isotherms suggests that the adsorption is weak (physicol) but this is contradicted by its observed irreversibility. The induction period and apparent energy of activation of development in the liquid system studied are shown to increase with gelatin concentration.The effect of a cationic wetting agent on adsorption and development is described. The specific gravity of silver developed under various conditions is recorded.The possibility is suggested that the firmly bound layer of gelatin on emulsion groins, creates a "thermal" barrier as a result of a difference (not proven) in the heat of adsorptions to silver hol1de and silver. Loosely bound gelatin is believed to form a conventional negative charge barrier.     

AgBr/I纳米粒子乳剂的制备及性能研究

用络合—沉淀法制备了卤化银含量３０ｇ／Ｌ，粒子大小２０ｎｍ以下的ＡｇＢｒ／Ｉ纳米粒子乳剂，研究发现：ＡｇＢｒ／Ｉ纳米粒子表现出较大的表面活性，并由此导致了其乳剂具有比常规乳剂低得多的感光度和高得多的灰雾，乳剂的最佳碘含量增加到了１１％，硫增感对纳米粒子乳剂没有效果，但硫加金增感表现出有效性。     

A Practical Method of Personnel Monitoring for Beta Radiations Using Photographic Emulsions

A practical system for the personnel monitoring of β radiations has been devised employing photographic emulsions together with a system of plastic filters. Beta-ray dose rates were measured with an extrapolation chamber in rads in soft tissue and the sources of β radiation were manufactured using pure β emitters with maximum energies ranging from 0·17 to 3·5 MeV. Measurements show the most suitable system to be one which divides the film into three areas, two of which are covered with plastic filters of thickness 50 mg/cm² and 300 mg/cm² respectively, whilst the other is unfiltered. The method of calibration of this filter system is described, together with a method of dose estimation for single doses of β radiation and the majority of β-γ ray mixtures. Certain problems regarding calibration and dose evaluation are discussed together with several miscellaneous problems pertinent to personnel dosimetry of βs rays with films.     

The Computation of the Response of Model Emulsion Layers Part I. Principles

The technique of residual grain size analysis gives for each size-class of grains in an emulsion the proportion of grains developed, as a function of the exposure expressed as the average number of quanta absorbed. A method has been found for disentangling the effect of random quantum suctuations, to find the proportion of grains which, under the given conditions, were rendered developable by the various integral numbers of quanta. The three curves so for analyzed suggest that three or four is the minimum number of quanta required for developability.     

Relationships Between Sensitometric and Optical Properties of Photographic Emulsion Layers with Particular Reference to the Wave-Length Variation of Sensitivity*

The influence of light scatter within an emulsion layer on its speed in terms of incident exposure, and of the diminution of intensity through the layer on H. and D. curve shape are discussed. The various considerations are combined in an expression for the wave-length variation of sensitivity of a non-optically sensitized emulsion. There are three wave-length dependent terms in the expression:

(a) The grain absorption factor, which is directly proportional to the product of the absorption coefficient, k, of the silver halide and the thickness of the grain, if the product is small.

(b) The factor by which intensity is increased in the top single-grain-layer of the multilayer owing to scatter. This is $$\{1+\frac{R\left(1+r\right)}{\left(1?r\right)}\}$$ where is the external reflection factor of the emulsion, and r the internal reflection factor for diffuse radiation.

(c) The exposure wastage due to self-absorption in the multilayer. For production of half-saturation density this factor is lO_?12, where ? is the unexposed emulsion density.

Following the same principles the wave-length variation of sensitometric characteristics of an emulsion coating in the optically sensitized region can be deduced, given the wave-length variation in shape and location against the incident exposure axis of the H. and D. curve of a single-grain-layer of the emulsion.

The validity of the separate terms, and hence of the theory as a whole, is demonstrated by published data or the results of experiments specially devised and carried out for this purpose.     

铱盐掺杂对卤化银乳剂照相性能的影响

本文阐述了一项用铱盐对溴碘化银T颗粒乳剂的增感实验研究，实验结果说明，在卤化银颗粒内部形成的铱增感感光中心，捕获光电子后在颗粒内部形成潜影，因而会降低感光度，而颗粒表面形成的铱增感感光中心能形成表面潜影，从而提高乳剂感光度。     

The Absorption Cross Section for Light of the Silver Grains in Photographic Deposits

Estimations of projection area of silver grains in photographic deposits were made on photomicrographs as well as counts of grains per unit area. Density of the deposit was calculated from these data employing known formulae. These were found smaller by a factor of 2-3 when compared with densities measured in diffuse light. The absorption cross section of grains for light considerably greater than their projective area is concluded. The results are in agreement with those obtained by other authors, which were, however, interpreted in a different way.     

鱼明胶在照相乳剂中的应用研究(I)鱼明胶特性分析

对鱼明胶特性分析表明,鱼明胶分子量分布中主要为α组分,γ组分几乎不存在; 其杂质铁含量较高, 且以三价铁占优势, 为总铁量的９５ ％ ;经 Ｄ４１２ 离子交换树脂处理可有效去除杂质铁,同时部分含微量活性硫成分也被去除,离子交换去除 Ｆｅ３ ＋ ／ Ｓ２ Ｏ２ －３ 比例为２∶１ 。推测使用鱼明胶可方便地制备超细颗粒乳剂,但不利于达到较高的感光度。     

The Reliability of Bleaching Techniques for the Determination of Latent Image Distribution in Silver Bromide and Iodobromide Emulsions*

The reliability of various bleaching Techniques was studied on the basis that a bleach should destroy surface latent image compleldy and that the internal speed should be independent of the precise bleaching conditions ond be as high as possible. Only two treatments satisfied these conditions. These were a potassium-ferricyanide-phenosafranine bleach and a silver-dichramale bleach ofter a washing treatment.     

改进乳剂层制作,提高彩色还原质量

本文从乳剂的光谱感光特性、主成色剂及Mask、DIR、DIAR等功能性成色剂的研究应用,以及涂层结构等方面讨论提高彩色负片彩色还原质量的方法。     

Photographic Properties of Polyethylene Oxide II. Effect of PEO on the Growth Habit of Silver Halide Grains

The effect of polyethylene oxide (PEO) on the growth hobit of silver iodobromide emulsion groins was investigated. Cubic (100) and tetradecahedral (100 + 111) iodobromide groins become more octahedral (111) in shope in the presence of PEO. The effect increased with increasing iodide content, while pure bromide grains were little influenced by PEO.     

物证检验摄影中灵活运用感光材料特性

本文介绍了部分常见感光材料特性,阐述在刑事物证检验摄影中如何运用感光材料特性,使一些痕迹的拍摄取得满意效果,并介绍了两个案例应用情况。     

Fatigue studies of high-palladium dental casting alloys: Part I. Fatigue limits and fracture characteristics*

The fatigue limits and fracture characteristics for a Pd–Cu–Ga alloy and a Pd–Ga alloy were studied. The alloys were cast into tensile test bars with gauge diameter of 3 mm and gauge length of 15 mm, and the surfaces of the castings were neither air-abraded nor polished after removal from the investment. Specimens were prepared from all-new metal (not previously melted), a combination of 50% new metal and 50% old metal (previously melted one time) and 100% old metal. The cast bars were subjected to heat treatment simulating the complete firing cycles for dental porcelain, and fatigued in air at room temperature under uniaxial tension-compression stress at 10 Hz and a ratio of tensile stress amplitude to compressive stress amplitude (R-ratio) of –1. The alloy microstructures and fracture surfaces were examined with a scanning electron microscope (SEM). Results showed that the fatigue limits at 2 x 10⁶cycles of the Pd–Cu–Ga and Pd–Ga alloys were approximately 0.20 and 0.15 of their 0.1% yield strength (YS) in tension, respectively. The fatigue resistance for specimens from both alloys containing 50% old metal and 50% new metal was comparable to that of specimens containing all-new metal, although this decreased dramatically for Pd–Cu–Ga alloy specimens containing all-old metal. The fatigue resistance of the Pd–Cu–Ga alloy subjected to heat treatment simulating the porcelain firing cycles was not adversely affected by remnants of the original as-cast dendritic microstructure that remained in the relatively large test specimens. A longer heat treatment than recommended by the manufacturer for the porcelain firing cycles is needed to completely eliminate the as-cast dendritic structure in these specimens. The Pd–Cu–Ga alloy exhibited superior fatigue resistance to the Pd–Ga alloy, which has an equiaxed-grain microstructure and lower yield strength.     

铱盐对卤化银照相乳剂性能的影响

研究了在乳化开始及乳化过程中添加铱盐（ＮＨ４）２ＩｒＣｌ６对乳剂照相性能的影响，并用设计出的可行方法测定了乳化开始时加入的铱在卤化银晶体中的分布。进一步说明了铱在卤化银晶体中的电子陷阱作用。