Photographic Speed Research Articles

Fetal Response to Sound and Light: Possible Fetal Education?

Purpose: To assess fetal well-being and education ability by fetal response to sound and light. Material: Intrauterine fetuses in late pregnancy. Methods: The sound source was a loud speaker connected to an audioamplifier, of which source was sine waves, generated in a stimulator. The sound power was measured by an audiometer. The loud speaker was placed at the pregnant abdomen. A photographic speed light, of which guide number was 25, was flushed at pregnant abdomen around at fetal face, in the photic stimulation. Results: Acoustic and visual stimulation effects were fetal movements and heart rate (FHR) acceleration in fetal actocardiogram. The stimulation with 1,000 Hz 80 decibel (dB) sound for 2 S produced positive effects at 28 weeks, while 60 dB sounds achieved positive effects in 40 weeks, namely, sound sensitivity increased 10 folds in late pregnancy. Although foetuses responded to 250 and 500 Hz sound in 28 and 40 weeks, sound intensity reduction was insignificant. Positive results to photic stimulation were noted in 23 or later weeks and 77% cases achieved positive results in 40 weeks. Discussion: Positive effect of sound and light stimulation was fetal movements and FHR acceleration, which were the sign of healthy fetal brain, while, significant sound power reduction was noted only in 1,000 Hz, higher frequency than maternal voice, thus, fetal education will not be expected, and mother voice should be changed to 1,000 Hz using a voice changer in fetal education, however, healthy fetal hearing is expected by the response to 250-1,000 Hz sound and the response to flush light is the sign of healthy fetal retina and light sensing.

Photographs of Early Ether Anesthesia in Boston

Photographs of Early Ether Anesthesia in Boston

Doping of AgHal heterophase grains by [IrCl6]3− ions

The influence of the doping of heterocontacting AgBr/AgBr(I) and AgBr/AgCl grains by [IrCl6]3− ions on photographic speed was investigated. Isometric and tabular crystals were used as a substrate. The incorporation of doping ions into the heterocontact zone was found to result in a change in the kinetics of the photoinduced charge carrier interaction. The optimal doping ion concentration allows the photographic speed increase and high-intensity reciprocal failure (HIRF) decrease to be to revealed. The photographic speed and HIRF values are shown to depend essentially on crystal habit. Based on the experimental data, a phenomenological model of the photoprocess in doped heterophase AgHal grains is suggested.

New basis for measuring the size distribution of bubbles

The use of air bubbles of varying size distribution in ore and wastewater treatment, including conventional (froth) and dissolved air flotation (DAF), Jameson flotation cell and Microcel (among others), has attracted much interest recently. These flotation processes are governed by the physical characteristics of the bubbles as well as the particles, and therefore it is necessary to investigate accurately the size distribution of bubbles that are generated. A new method was developed to measure the bubble size distribution based on the bubbles’ capture (without movement) combining microscopy with digital image processing procedures. The technique (LTM-BSizer) employs a sampler to draw bubbles, rising in a column, into a special viewing chamber and exposes them to a digital camera after they have decelerated and stopped. Thus common problems related to the movement of bubbles, namely focus, illumination, photographic speed and bubbles overlapping are all overcome. Results obtained are in good correlation with some values reported with the traditional image analysis method and show that using this technique accurate size distributions can be produced conveniently and efficiently. The influence of some operational parameters on the formation of bubbles was studied. It is believed that the bubble size measurement technique developed in this study will assist understanding and improvement of the DAF and conventional fines and ultrafines mineral flotation, from both theoretical and practical viewpoints.

Preservative characteristics of photographic films and papers on the speed method

As archives, photograph is the evident records of historical facts and experiences. Thus, it is worth preserving. Unlike other documents silver halide photographic films and prints are quite sensitive to environmental factors such as light, temperature and humidity, which demands careful treatment in preservation. This study was carried out to select popular photographic films and papers on the market, to examine their photographic speeds (or sensitivities) and to compare and analyze their preservative features after keeping them some time in a weather-o-meter. Consequently, B/W materials were superior to color ones in preservation. And films were better than papers in the same manner. But we were not able to observe remarkable differences among material's manufacturers.

Sulphide centres on (111) AgBr surfaces: energy levels and computer simulated sensitometry

Sensitometric and spectroscopic techniques are used to characterize sensitizer centres produced by sulphur sensitization of AgBr octahedra. Activation energies for long-wavelength sensitivity were independent of thiosulphate concentration for the single-sulphide centres (550 nm), but showed a concentration dependence for the multiple-sulphide centres (700 nm). The achievement of maximum photographic speed is associated with the production of the multiple-sulphide centres. Using activation energies for long-wavelength sensitivity, with the lowest one for the multiple-sulphide centres being taken as closest to reality, an energy level scheme was constructed for the two sulphide centres. The single-sulphide centres are estimated to have an electron trap depth between 0 and 0.1 eV, whereas the multiple-sulphide centres have trap depths between 0.25 and 0.45 eV. Deconvolution of thiosulphate-induced absorption spectra suggested that only 65 per cent of the converted thiosulphtate is photographically active and that the single-sulphide centres are the predominant sulphide species. Computer simulated sensitometry based on these ideas was consistent with experimental sensitometry. Computer simulation of the sensitometry for the optimum thiosulphate concentration required a small concentration of the multiple-sulphide centres. Attempts to simulate the sensitometry of the oversensitized emulsion were less successful. Computer simulations based on the single-sulphide centres acting as hole traps were inconsistent with the experimental data.

Thiocyanate Free Gold Latensification

The properties of a thiocyanate free gold latensification solution are explored. A dilute solution of potassium tetrachloroaurate (III) produces photographic speeds almost as high as the conventional gold latensification formulation that contains potassium thiocyanate. During latensification, gold plates onto sub-image centers rather than replacing silver in those centers.

Sulfide Centers on (111) AgBr Surfaces: Characterization

Sensitometric and spectroscopic techniques are used to characterize sensitizer centers produced by sulfur sensitization of AgBr octahedra. Sulfur sensitization primarily affects the long wavelength sensitivity in two spectral regions—around 550 nm and around 650–700 nm. The concentration dependence of the long wavelength sensitivity in these two regions shows the former to be associated with single-sulfide centers and the latter to be associated with double-sulfide centers. The achievement of maximum photographic speed is associated with the production of the double-sulfide centers. A prominent 495 nm peak is observed in diffuse reflectance spectroscopy of these emulsions that is not observed in the long wavelength sensitivity measurements. This peak is assigned to a product of the sulfur sensitization that is not photographically active.

Two-Electron Sensitization: A New Concept for Silver Halide Photography

The primary process in conventional photography involves electron transfer from an excited dye molecule into the conduction band of a silver halide microcrystal. Repeated events of this type ultimately lead to formation of a small, stable cluster of silver atoms in the silver halide that acts as the latent image, along with the one-electron oxidized forms of the dye molecules. Here we describe a new concept for increasing the efficiency of photographic systems, two-electron sensitization, which makes use of the chemical potential stored in the oxidized dyes. In conventional photography, subsequent reactions of the oxidized dyes are not controlled and may in fact include counterproductive return electron transfer reactions (recombination). In the two-electron sensitization scheme, an appropriately designed electron donor molecule, X−Y, that is added to the photographic dispersion transfers an electron to the oxidized dye to give a radical cation, X−Y•+. The X−Y•+ then undergoes a fragmentation reaction to give a radical, X•, and a stable cation, Y+. The radical X• is chosen to be sufficiently reducing so that it can inject an electron into the silver halide conduction band. In this way, the oxidized dye, which is a strong oxidant, is replaced by the radical, X•, which is a strong reductant. The two-electron transfer scheme has the potential of doubling the photographic speed because two electrons are injected per absorbed photon. Here we describe the mechanistic details of the two-electron sensitization scheme and the structural and energetic criteria for the X−Y molecules. Several electron-rich carboxylate molecules that meet these criteria have been identified. Solution-phase experiments to determine the fragmentation (decarboxylation) kinetics and the reducing power of the resultant radicals are described. Photographic data demonstrate that increases in sensitivity by factors approaching 2 can be obtained, confirming the viability of the two-electron sensitization concept.

Production of superhigh contrast by dyes

A new role for dyes in the photographic development system has been observed. Contrast and apparent photographic speed were substantially increased when a photographic film was developed using a developer containing an aminophenol-type developing agent and sodium ascorbate in the presence of cyaninc and merocyaninc dyes. It was found that the addition level of sodium ascorbate greatly affected the photographic speed and contrast. It was suggested that the dyes acted as contrast enhancing agents during development.

副露光法による高感度X線フィルムの増感

Film available on the market can be sensitized by special processing. We achieved further sensitization of high-sensitivity x-ray film by using a technique of simple auxiliary exposure. The photographic speed of the sensitizing film was 1.5 times greater than that of the original film. When the sensitizing film is combined with a super-high-sensitivity intensifying screen, the total relative speed reaches 2400, a value that up to now has never been realized in a radiographic system. Our sensitization technique is very useful for decreasing medical radiation doses. Moreover, using the increase in density obtained by sensitization, we estimated the number of latent sub-image specks, which is related to the sensitizing effect.

Development-accelerator-releasing (DAR) coupler: Part IV. The effect of the DAR couplers with different hydrazines on the photographic characteristics of color negative material

The effect of five development-accelerator-releasing (DAR) couplers derived from different hydrazines on the photographic characteristics of color negative material has been studied It was found that the development-accelerator-releasing couplers examined may be used together with cyan couplers in a color negative material to increase the photographic speed; no apparent difference was observed with the different hydrazines.

Color photographic development accelerators. part v: selective development acceleration of hydrazine compounds 1,3,4-thiadiazole heterocyclic system

Photographic speed can be increased by incorporating selective development accelerators (hydrazine derivatives with adsorbed groups) into several types of silver halide emulsion because of the stronger accelerating action on image development than on fog formation. The development acceleration of the selective development accelerators depends on the pH of the developer. The higher the pH of the developer, the stronger the development acceleration of these compounds. When the pH of the developer rises to 12.50, the ‘hydrazine effect’ (super high contrast and short toe) is obtained. The accelerating action of the selective development accelerators appears over a wider pH range of developer, whereas that of the hydrazine compounds without adsorbed groups occurs only at higher pH of the developer (pH > 11.50) under the same experimental conditions.

Color photographic development accelerators: Part III. Synthesis and properties of a new class of selective development accelerators

Several new selective development accelerators, viz. 2-[4-(2-acyl]hydrazino) anilinocarbonylmethyl] thio-5-alkylthio-1,3,4-thiadiazoles were synthesized. The structure of the compounds was confirmed by elemental analysis, MS, IR and 1H-NMR. Their effect on the photographic characteristics of color negative material was studied and it was found that the photographic speed can be greatly increased with the inclusion of these compounds in the color negative material.

Color photographic development accelerators part II-effect of development-accelerator-releasing colorless couplers on the photographic characteristics of color negative material

The effect of five development-accelerator-releasing colorless couplers on the photographic characteristics of color negative material has been studied. It was found that the development-accelerator-releasing colorless couplers examined may he used together with the cyan and magenta image couplers in a color negative material to increase the photographic speed.

A New Aspect of Photographic Speed (3)

A New Aspect of Photographic Speed (3)

Photopolymer Systems for Lithographic Applications

Abstract Photopolymers play an important role in technical imaging systems. Several basic principles of photopolymer crosslinking and photoinduced radical polymerization systems will be reviewed. Photopolymers are amorphous solids and the photo crosslinking reaction (e.g. increase in molecular weight) takes place in the glassy state. Their ultimate photographic speed may be calculated from basic physical properties of the irradiated areas. A continuous decrease of quantum yield during irradiation is characteristic for the photoreaction. The response to light is made possible by built in or added chromophores that can undergo different reactions depending upon their nature. In a photoinduced polymerization the photo initiator decays into a radical pair when exposed to radiation. The photochemical reaction is amplified by a subsequent polymerization with multi functional reactive monomers to form an insoluble network. The photographic speed is governed by several factors including the quantum yield of cleav...

The Influence of Silver Halide Laydown on the Speed of Colour Negative Materials

AbstractAn increase in photographic speed is observed in colour negative materials when silver halide laydown (mass per unit area) is increased and with G-41 development. It is shown that this phenomenon is due to an increase in the degree of development per silver halide grain occurring only in the lower sensitometric scale. In opposition to this developed silver increase is a reduction in the expected number of developed grains per unit area. The effect of these developed silver phenomena on dye granularity is described with the use of a quantitative model. It is also shown that optical factors play only a minor part in the observed speed variations.

A New Aspect of Photographic Speed (2)

A New Aspect of Photographic Speed (2)

Image Quality and Photographic Speed of Color Negative Film

Image Quality and Photographic Speed of Color Negative Film