Latent Image Specks Research Articles

Dispersion of Latent Image Specks in Silver-salt Photographic Materials Formed by Exposure to an Electron Beam with Constant Energy

Dispersion of Latent Image Specks in Silver-salt Photographic Materials Formed by Exposure to an Electron Beam with Constant Energy

Measurement of the Deposited Energy of Tracks of High-Energy Particles Using the Line Density of Latent Image Specks

Measurement of the Deposited Energy of Tracks of High-Energy Particles Using the Line Density of Latent Image Specks

Preparation of Gold Nanoparticles in a Layer of Gelatin Film Using Photographic Materials. VII. Acceleration of Gold Deposition by Using Ascorbic Acid

Abstract The preparation of gold nanoparticles using silver-salt photographic materials and a method of gold-deposition development are investigated. Although gold rapidly precipitated in the gold-deposition developer when ascorbic acid was added, gold atoms were deposited only on the exposed areas of the photographic plate when the plate was immersed in the solution. While the deposition proceeds slowly via the disproportionation reaction of gold(I) ions in the absence of ascorbic acid, the addition of ascorbic acid accelerates the deposition rate significantly and increases the photosensitivity of the photographic plate. The gold deposition is catalyzed by photolytic silver specks, called latent image specks, on silver halide grains. Absorption spectra and TEM observations suggest a broadening of the particle size distribution, and this indicates that the difference in the catalytic activities of the photolytic silver specks between the two reactions is due to the difference in the critical size of the silver specks for triggering the deposition. Because the catalysts were prepared using light, light-based control of the catalytic properties may be possible.

Preparation of Gold Nanoparticles Using Photographic Materials (6): Effect of Thiocyanate Ions

The authors have previously reported a method for preparing gold nanoparticles using silver halide photographic materials and gold deposition development. This process was investigated from the viewpoint of the effect of thiocyanate ion concentration. Gold particles are formed on latent image specks on the exposed silver halide grains by the disproportionation reaction of gold(I) thiocyanate complex ions. The ratio A of gold ions to thiocyanate ions in preparing the gold(I) thiocyanate complex affects gold deposition; that is, the rate of gold deposition increases when the abovementioned ratio A increases from 1:10 to 1:3. Optical measurement, atomic absorption spectroscopy, and electron microscopic observation indicate that the growth rate of gold nanoparticles does not depend on the ratio A, while the total mass of gold atoms increases with an increase in the ratio A. The mass increase is due to the increase not in size but in the number of gold particles. Excess thiocyanate ions inhibit the deposition of gold atoms on latent image specks.

Preparation of Gold Nanoparticles in a Gelatin Layer Film Using Photographic Materials (5): Characteristics of Gold Nanoparticles Prepared on an Ultrafine Grain Photographic Emulsion

The authors report a process for the preparation of gold nanoparticles in a gelatin layer. This process is similar to the photographic process of gold development or gold latensification, where gold atoms are deposited on the exposed area of photographic material when it is immersed in a gold(I) thiocyanate complex solution. Gold particles have gained prominence for their nonlinear optical effect, the intensity of which depends on the density of the particles in the layer. The authors attempted to condense the particles using a photographic plate for hologram recording; this plate was made of an ultrafine grain emulsion because this emulsion was believed to be conducive to condensation. The characteristics of the particles were analyzed using photographic characteristic curves, absorption spectra, and size distributions. The characteristic curves rose gradually with the immersion period and finally showed a very high contrast curve. A sharp and strong plasmon absorption was observed at around 550 nm at high exposure values, while the peak exhibited a redshift and broadening at lower exposure values. The diameter of the particle increased proportionally with the square root of the immersion period. The growth rate decreased with the exposure value and was larger with high intensity exposure. The dependence on the exposure value was explained by the competition for the gold ion due to the high density of latent image specks. The larger growth rate with high intensity exposure was also explained by the low density of the latent image specks due to high intensity reciprocity failure.

Dispersion of latent image specks formed by electron beam exposure with constant energy

Dispersion of latent image specks formed by electron beam exposure with constant energy

Preparation of gold clusters in gelatin layer film using photographic film — 4: Effect of photographic materials

The effect of the properties of photographic materials on the preparation of gold clusters in a gelatin layer using a photographic film was examined. The cluster are formed by reducing a gold(I)–thiocyanate complex solution on latent image specks in emulsion grains. Gold clusters are marked as a non-linear optical material, and it was necessary for this purpose to condense the gold clusters in the layer. This was attempted by two methods. The first was to increase the emulsion grains in the layer, and the second was to increase the number of latent image specks on a grain. An ultrafine grain emulsion was applied for the former, while a high-intensity exposure and chemically sensitized emulsions were used to induce the dispersion of latent image specks for the latter. The characteristics of the clusters prepared from those emulsions were compared by absorption spectrum and size distribution. Both methods increased the plasmon absorption due to the gold clusters. The size of the clusters was similar, while absorbance increased with the sulphur-sensitization level. These results suggested that both were effective in condensing the gold clusters in the layer.

Dispersion of Latent Image Specks at Sulfur+Gold-Sensitized Emulsions Exposed with β-Radiation

Dispersion of Latent Image Specks at Sulfur+Gold-Sensitized Emulsions Exposed with β-Radiation

Preparation of Gelatin Layer Film with Gold Clusters in Using Photographic Film

A gelatin layer film with gold clusters is produced by taking advantage of the photosensitivity of silver halide photography. Through exposure silver specks, which are called latent-image specks and are composed of several reduced silver atoms, are formed on the surface of silver halide grains in the photographic film. As the latent-image specks act as a catalyst for redox reaction, reduced gold atoms are deposited on the latent-image specks when the exposed film is immersed in a gold (I) thiocyanate complex solution for 5–20 days. Subsequently, when the silver halide grains are dissolved and removed, the gelatin layer film with gold clusters remains. The film produced by this method is purple and showed an absorption spectrum having a maximum of approximately 560 nm as a result of plasmon absorption. The clusters continued to grow with immersion time, and the growth rate increased as the concentration of the gold complex solution was increased. The cluster diameter changed from 20 nm to 100 nm. By this method, it is possible to produce a gelatin film of a large area with evenly dispersed gold clusters, and since it is produced only on the exposed area, pattern forming is also possible.

Dispersion of latent image specks on reduction-sensitized emulsions

The dispersion of latent image specks (LISs) on reduction-sensitized octahedral grain (Oct) and cubic grain (Cub) emulsions that were exposed to light of various intensity levels or to a radiation was studied. The number and distribution of LISs on a grain were determined with arrested development or gold deposition techniques. The sensitized Oct emulsions were sensitive to extra-low-intensity (24 or 48 h) exposure. This exposure displayed a narrow distribution with a one-speck-per-grain pattern. This changed to a broad distribution for 1 s exposure, which obeyed the Poisson distribution law at the highest sensitization level. These suggested that there were P centres present acting as precursors of LISs and inducing dispersion. The distribution for high-intensity (10−4 s) exposure obeyed the Poisson law for sensitized Oct and Cub emulsions. This dispersion of LISs occurred even in absence of the effective electron traps, when the supply rate of photoelectrons was high.The distribution of LISs was widely spread on exposure to α radiation, and the z and vb values were calculated, where z was the number of LISs formed when an a particle hit a grain once and vb was the number of LISs at which its linear increase with increasing number of striking a particles ceased and saturation began. Both z and vb increased with increasing sensitization level for the Oct emulsions, while they were almost constant for the Cub emulsions. These reflected the increase in or the absence of P centres. It was also suggested that the photolytic Ag3 speck is more effective than the Ag2 P centre as an electron trap.

Delayed Formation of Latent Image Specks in a Vacuum on the Tetrazolium Compound Added Emulsion

Delayed Formation of Latent Image Specks in a Vacuum on the Tetrazolium Compound Added Emulsion

Study of the Delayed Formation of Latent Image Specks in a Vacuum for Emulsions with added Phenosafranine by the Arrested Development Technique

Effects of phenosafranine (Ps) on the delayed formation of latent image specks in a vacuum and on the dispersion of latent image specks at sulfur-sensitized octahedral grain emulsions were studied by the arrested development technique. Ps desensitized in room air especially at unsensitized emulsion, while it was not the case in a vacuum. Ps did not affect the dispersion of latent image specks in room air and in a vacuum as well, while high level of sulfur sensitization enhanced the dispersion. Low levels of Ps and sulfur sensitization depressed the delayed formation, and high levels of both enhanced it. The sulfur sensitization may enhance the delayed formation due to the dispersion of latent image specks, while Ps may do so due to the formation of single silver atom species (SSAS). An emulsion grain is divided into several domains and the delayed formation proceeds when a latent sub-image speck and SSAS form in the same domain. There are two types of small silver species; growing species and nongrowing. The former is a precursor of the latent image speck acting as an electron trap. The later, such as SSAS, cannot trap electrons and it requires a certain aggregation process to grow a larger speck.

Effect of Sulfur+Gold Sensitization on the Delayed Formation of Latent Image Specks in a Vacuum

Behavior of the delayed formation of latent image specks in a vacuum on sulfur+gold-sensitized emulsions with cubic and octahedral grains was studied. The fraction of developed grains P increased by storing in a vacuum after exposure. In the cubic grain emulsion P exhibited an exponential one-step increase. On the octahedral grain emulsion P indicated a two-step increase. The first step was exponential and the second step was S-shaped. The delayed formation diminished with the increase of sensitization level and disappeared completely at the highest level. Latent subimage specks in the sulfur+gold-sensitized emulsion were developable by absorbing one photon, but not by adding one silver atom in the delayed formation process. The mechanism of the two-step increase in developability is also discussed.

Principles of Microwave Absorption Technique Applied to AgX Microcrystals

Microwave absorption (MWA) enables contactless measurements of electronic transport properties in solids. MWA is the only method for studying the lifetimes and mobilities of the photogenerated charge carriers that depend on the recombination process of photoelectrons. Therefore MWA is a powerful tool to understand the influence of phase structures of point defects like Y−, Ir3+, Pb++, Cu++, etc., dislocations; and chemical and dye sensitization on the formation of latent image specks.

Sabattier Effect in Internally Sensitive Emulsions

From the study of the distribution of latent images and the Sabattier effect of emulsions with internally sensitized core–shell grains having uniform iodide distribution, it is found that the surface sensitivity decreases with increase of the internal sensitivity. To show a strong Sabattier effect, an emulsion should contain grains with both surface sensitivity centers and internal sensitivity centers, and they should be well matched. The ratio of the two sensitivities and the second exposure are two important factors that decide the kinds of Sabattier reversal. The results can be explained by the behavior of photoelectrons and photoholes within the silver halide grains during the two exposures and developments. The surface latent image specks formed during the first exposure are bleached by the photoholes during the second exposure, resulting in a reversed image.

Dispersion of Latent Image Specks Formed by β-Radiation of Sulfur-Sensitized Emulsions

Dispersion of latent-image specks formed by β-radiation was studied for sulfur-sensitized emulsions by means of the arrested development technique. The number of latent-image specks in one grain, n, was counted and the distribution of n was measured. The distribution is wider than that for grains exposed to light and split into two peaks at stronger sensitization levels. One was a broad peak at n ≥ 1 and the other was a sharp peak at n = 0. The average number of β-particles that strike one grain w, was evaluated statistically. The average number of latent-image specks in one grain v,increased with w. The relationship between w and v was linear at small w. It deviated upward for strongly sensitized emulsions and downward for weakly sensitized and unsensitized emulsions. The average number of latentimagespecks formed by one strike of a β-particle, z, was evaluated and it increased with the sensitization level. This value z is useful as a quantitative index of the dispersion of latent-image specks.

Dispersion of Latent Image Specks Formed by β-Radiation for Sulfur-Sensitized Cubic Grain Emulsions

Dispersion of Latent Image Specks Formed by β-Radiation for Sulfur-Sensitized Cubic Grain Emulsions

Dispersion of latent image specks at sulfur+gold-sensitized emulsions

Dispersion of latent image specks at sulfur+gold-sensitized emulsions

Some aspects of the delayed formation of latent image specks and the kinetic analysis of it

Some aspects of the delayed formation of latent image specks and the kinetic analysis of it

Characteristics of Photolitic Silver Microcluster from the Phenomenon of Delayed Formation of Latent Image Specks

Characteristics of Photolitic Silver Microcluster from the Phenomenon of Delayed Formation of Latent Image Specks