Emulsion Speed Research Articles

Humidity and Photographic Sensitivity

AbstractHumidity conditioning before exposure is found to cause significant losses in emulsion speed and with integral colour film the effects vary from layer to layer and from one manufacturer's product to another’s. It appears that colour sensitized emulsion is much more subject to conditioning than non-sensitized emulsion. Extremely dry conditions can increase speed above normal. Humidity conditioning after exposure is more progressive with time and the mechanism in this case is attributed to an effect on the rate of latent image regression. The literature seems surprisingly deficient in respect of serious studies on this subject.

Light Fastness Evaluation of Colour Photographs

AbstractThe light fastness on the British Standard (B.S.) scale of a variety of examples of colour photographs, both transparencies and prints, has been determined and the possible lifetimes under normal conditions, before fading is noticeable, have been estimated.In transparencies from reversal films there appears to be a correlation between emulsion speed and speed of fading: the slowest film gives the best fastness, its colours are graded about 4 (on the B.S. scale of J to 8) in medium shade depths. This is probably adequate for occasional projection, though poor by textile standards, corresponding with a possible useful life of about 4 hours under continuous exposure in a modern projector. The fastest reversal films (l00 ASA and above) are very poor indeed and are graded about J on the scale, corresponding with a possible useful life of only about 0.5 hours in a projector.Colour-developed paper prints are graded between J and 2, and estimated to have a useful life of between 4 and 12 months under cont...

Absolute Magnitudes from Trigonometric and Statistical Parallaxes

The attainable accuracy of photographic trigonometric parallaxes may be improved by the use of modern measuring engines, larger number of exposures, facilitated by increased speed of emulsions, more refined knowledge of reduction to absolute parallax. Systematic errors remain an obstacle both in trigonometric and statistical parallaxes.With an attainable goal of ±0″.002 for the probable error of a parallax it appears difficult to obtain absolute magnitudes with a probable error less than 0.2 mag. for stars beyond 20 pc.

Photographic Effects of Phenosafranine and Sulfur Sensitization in Various Silver lodobromide Grains

The degrees of the increases of the surface speeds due to the presence of phenosafranine and to sulfur sensitization have been measured in the AgBrI emulsions prepared by various procedures, and compared with the ratios of internal/surface speeds of the corresponding undyed and unsensitized (control) emulsions. It has been found that there are strong correlation between them both in the case of the addition of phenosafranine to the emulsion and in the case of sulfur sensitization. It has been suggested that the sensitivity centers in sulfur sensitiza- tion as well as phenosafranine molecules increase the surface speed of the emulsions by acting as electron traps, and that the degree of the increase of surface speed increases with increasing the ratio of internal/surface speed of the control emulsion.

Relation of Degree of Sensitization and Desensitization by Complex Ions of Rhodium(III), Osmium(IV), Ruthenium(IV), and Platinum(IV) with Nature of Primitive Emulsions

Hexachlororhodate0n, hexachloroosmate(N), hexachlororuthenate(V), and hexacl: iloroplatinate (N) decreased both surface and internal speeds of silver bromide emulsions, and increased surface speeds of silver iodobromide emulsions, although they decreased the internal speeds of the silver iodobromide emulsions, when they were added to the emulsions before coating. The degree of sensitization increased and that of desensitization decreased with the increasing ratio of internal/ surface speed of primitive emulsions: These results are consistent with the idea that the complex ions act as electron traps at the grain surface which are not necessarily efficient for latent image formation, since the surface speed is low owing to the capture of photoelectrons by internal sites in the case of grains with high ratio of internal/surface speed.

The absolute intensity calibration of photographic emulsions in the vacuum ultraviolet

The response has been measured of Kodak S.W.R. and SC-7 films and Ilford Q1 plates at 584, 736, and 920 AA and of SWR film at 1216 AA. The absolute values of the radiance were measured with a rare gas ionization chamber. The inertia was found to be the most useful measure of emulsion speed.

分光増感色素による乳剤の固有感度の減少に対するイオウ増感の影響

分光増感色素による乳剤の固有感度の減少に対するイオウ増感の影響

Superadditivity of Phenidone/Pyrogallol Developers

AbstractA useful developer can be formulated with pyrogallol if it is used in combination with Phenidone. The developer activity of the mixture is far superior to that of the individual components used separately, and closely matches the developer activity of Phenidone/hydroquinone solutions. A low pH formulation, consisting only of pyrogallol, Phenidone, and sodium sulphite (pH 8.30) yields a higher emulsion speed for the same development time than does a conventional fine grain developer like Eastman Kodak D-76. Since the pH of this developer is low, auto-oxidation is no problem and the developer is stable.This paper discusses the superadditive effect of the pyrogallol-Phenidone developer and compares its activity with metol-pyrogallol and hydroquinone-Phenidone combinations. A stable, high pH, Phenidonepyrogallol developer is also described that makes use of ascorbic acid rather than sodium sulphite as the preservative.

Enhancement of Photographic Speed by Electric Fields

A hypotheses was suggested that intense electric field would increase the speed of emulsion. This was tested by Jerome Rothstein (1959) for light and found to hold. The hypotheses is now being checked by the author for x-ray exposure and in general the effect of pulsed electric fields on emulsion. At this time no real conclusive results have been found to either prove or disprove the theory, but many results have been obtained concerning the increase in speed of emulsions by electric fields.

Factors determining film exposure in cineradiography.

In the practical application of cineradiography, the radiologist needs a reliable and speedy determination of proper film exposure. Failure to achieve this greatly hampers the full realization of the clinical potential of this method of studying dynamic motion and restricts the extension of its usefulness to other areas of diagnostic roentgenology. As with spot-film radiography, some type of phototiming would be a desirable means of assuring correct film density for any combination of emulsion speed, framing rate, object density, and radiation exposure factors. Unfortunately, phototiming as we know it in conventional radiography cannot be readily achieved without a radical change in commercially available cine cameras. The compact design of these cameras does not provide sufficient space for the insertion of even a small conventional photocell into the area of the filming aperture. It is conceivable that a tiny selenium (cadmium sulfite) type photosensitive crystal could be placed in the camera, but this ...

A New Photographic Developer for Astronomical Work.

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A New Photographic Developer for Astronomical Work. Fernie, J. D. Abstract Experiments applying a new, commercially available developer, Acufine, to astronomical spectroscopic plates are described. Sensitometric measurements indicate that this developer effectively increases the emulsion speed by half a magnitude, compared to development in D-19, while simultaneously producing a finer grain. Contrast is moderate, and developing times are about 6 min at 700 F. When used with its replenisher, Acufine appears to be stable and have a long life. Costs, while slightly higher than for D-19, are negligible compared to the saving in telescope time. Publication: The Astronomical Journal Pub Date: March 1962 DOI: 10.1086/108818 Bibcode: 1962AJ.....67Q.272F full text sources ADS |

The Electrada Corporation

The Electrada Corporation of Los Angeles has announced plans for a new “Photo‐Optronic Laboratory”, described as “one of the first commercial undertakings to study the nature of light in its application to electronics and chemistry”. The laboratory, now under construction at Culver City. Calif., will be equipped to perform very precise measurements of the physical and chemical effects of light (such as the speed and resolution of film emulsions and other light‐sensitive coatings) within the microsecond‐micron range. In addition, special devices will be installed to study the effects of light on crystals and photoconductors. The laboratory will be headed by Robert M. Lemmen, and is expected to be in operation before the end of the year.

A new slit-lamp color camera.

Although color photographs of good quality have been possible through the conventional slit-lamp microscope with the use of exposures of from a half to one second, it is essential to improve on these speeds if any condition is to be photographed without showing the blur that invariably accompanies slight iris movements, lacrimal flow after blinking, and the movement of the conjunctiva across the sclera that sometimes takes place with concentrated fixation effort. The reduction of shutter speeds to 1/20 or 1/30 second requires either increased film emulsion speed, greater illumination, or lens systems with a greater light transmission. I have tried all three, and the results of the trials showed that faster film emulsions produce less accurate color reproduction at present, while increase of illumination has to be disproportionate in order to produce an increase of shutter speed. Indeed there is probably a limit to how much light can be

Comparative clinical evaluation of radiographs exposed with films of different emulsion speed

In order to investigate the effect of the use of faster emulsion speed x-ray film on radiograph quality (a study directed ultimately at decreasing the exposure of the patient and/or operator to x-radition), individual and comparative evaluations of the quality of x-ray images resulting from the exposure of the same areas of the mouth using x-ray film of three different emulsion speeds were made. One film of each of four different areas in the mouth was exposed with each of the three x-ray films (DuPont standard slow, S-1, moderately fast, D-1, and very fast, “Lightning Fast”) in each of thirty-five patients. All films were processed under conditions standard for all three films. Blind study and evaluation of the resulting roentgenograms revealed that, in terms of both individual excellence and comparative performance, use of both the moderately fast and slow standard speed films was found to result in roentgenograms superior to the very fast films in a greater percentage of instances. There was relatively little to choose in terms of over-all clarity, variations in density, and visibility of detail between the moderately fast and slow speed standard films. However, many films exposed with the very fast x-ray film were judged excellent and many were judged to be best in performance when compared with the two slower films. This suggests that it is possible to obtain radiographs of the highest quality using the very fast speed film and indicates that further study of some of the critical factors in exposure time, target-film distance, and processing may result in a technique productive of very fast films of uniformly highgrade excellence. Although at present the routine use of very fast film with the short-cone technique is not indicated on the basis of this investigation, increased study of the use and performance of x-ray films with faster emulsion speeds seems highly desirable. Since the exposure of the slow and the moderately fast speed films was found productive of relatively equally excellent films, in terms of both individual quality and comparative performance, increased use of the moderately fast speed film is definitely indicated, due to decreased radiation exposure of the patient and the operator. Where maximum excellence of films is essential, as in the study of difficult to diagnose lesions or when magnification of radiographs is anticipated, the use of the standard slow speed film is still indicated.

Latensification of Multilayer Color Film

New color films of the negative-positive type have hastened the general trend from black-and-white to color in the motion-picture industry. In order to overcome low emulsion speed of these stocks which limits their use under certain location conditions, an attempt has been made to increase speed. In this paper a method of raising the speed of Eastman Negative Color 5248 from ASA 24 to ASA 80 without objectionable loss of contrast or color shift is described.

The site of reaction in direct photographic development. II. Kinetics of development initiated by gold nuclei

A visible gold image, consisting of roughly spherical particles varying in size up to 80 mμ in radius for the longest times of treatment, was obtained by bathing exposed photographic film in an aurous gold solution. The particles are formed by a “physical development” of the latent-image specks. Electron micrographs show that they are situated at the surface of the silver halide grains. The gold treatment increases the emulsion speed and the rate of direct development and decreases, but does not eliminate, the induction period in sulfite-free hydroquinone or p-hydroxyphenylglycine developers. The gold treatment does not change the relative dependence of the rate of development upon the hydroquinone concentration. The relatively small decrease which the gold treatment effects in the induction period is not in accord with Bagdasar'yan's mechanism of development or with electrode mechanisms which seek to explain the induction period on the basis of size and capacity of the development centers.

CHOOSING AN EMULSION AND PROCESSING TECHNIQUE FOR DAYLIGHT AERIAL PHOTOGRAPHY

Experiments are reported that show the relations existing between gamma, useful exposure range for aerial photography, maximum resolving power, and emulsion speed as determined by the resolving power criterion. Aero Super XX and Panatomic X, processed in various ways, were used for the experiments. The results are used to deduce the proper choice of emulsion and processing technique for ordinary daylight aerial photography where the main requirement is the acquisition of information.

A NEW CRITERION FOR MEASURING THE SPEED OF AERIAL PHOTOGRAPHIC EMULSIONS

Arguments are advanced to support a proposal that the speed of photographic emulsions intended for aerial photography be determined by the use of a resolving power criterion. A statistical summary of experimental results is given to show that on such a basis speed determinations can be made with sufficient reliability by different observers. The relation between speed and gamma is given for Aero Super XX.

The charge effect in relation to the kinetics of photographic development. IV. The variation of emulsion speed with charge. The action of complex developers

The charge effect in relation to the kinetics of photographic development. IV. The variation of emulsion speed with charge. The action of complex developers

Maximum emulsion speed in relation to the developing agent

Maximum emulsion speed and gamma values were obtained with a series of developing agents used under optimum conditions and in the absence of sodium sulfite. Seven of the eleven agents tested gave substantially the same values. The critical size and configuration of the latent-image center which will just promote development of a given grain must be substantially the same for each of these agents. The other four agents gave definitely lower speed values. No agent or combination of agents has been found which gives higher speed values. The conventional elon-hydroquinone developers which contain sulfite give only equal or somewhat lower values.