银盐照相的感光度极限：从光谱增感看其界限

序言用于照相感光材料的卤化银的光谱增感,是把卤化银原有的光谱感光度向长波可视范围扩展的技术,这对彩色照相是很重要的。有许多化合物被用作增感染料试验,并在实用上获得成功。现在,不仅为高感光度,就是为了谋求高的影像质量也要寻求最佳的吸收波长。但光谱增感的机理尚不完全清楚,对于染料的设计可说仍是个未知的领域。关于光谱增感机理及和卤化银的本质的相互作用,由于照相乳剂中添加了种类繁多的化合物而难以分析。同时又因光谱增感过     

卤化银技术20年一览

本文简单介绍了卤化银微晶技术的进步对彩色照相材料发展的影响,讨论了今后10年卤化银照相技术和材料的发展方向。     

热显影卤化银彩色照相材料

概述了热显影卤化银彩色照相材料的发展过程，介绍了这种照相材料的构成、成像原理以及所用主要有机材料的结构类型．     

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。     

21世纪照相展望

分析了１９和２０世纪卤化银照相的发展规律，对它在２１世纪的发展做了预测。分析表明，照相与自然界的过程（受光与光合作用）之间存在着一定的相似性。认为，自然界经过几个世纪长期演变形成的基本原理，诸如各种过程的细胞组织多级放大和化学编程，应用于照相过程必将对２１世纪照相科学的发展以新的推动力。     

卤化银照相在医学成像和印刷成像中的进展

卤化银照相在医学成像和印刷成像中的进展１．序言有关卤化银照相在彩色胶片和彩色相纸方面进展的评论已为数不少，因此有必要对黑白产品，如医学胶片、印刷胶片的进展应进行评价，以便确定未来的研究与开发。本文将回顾卤化银照相在医学和印刷成像方面３０年的历程，并展...     

硫代苯磺酸钠在照相乳剂中的应用

试验结果表明，标题化合物在各种组份的卤化银照相乳剂中分别显示抑制灰雾、或改进感光度和反差的作用，甚至对感光度和灰雾具有一致优良的性能。     

提高显影选择性增加影像密度

通过在显影液中综合应用有机和无机添加剂,影响显影剂的活性和含潜影卤化银微晶的性质,可使医用Ｘ射线胶片和黑白胶卷已曝光和未曝光卤化银之间的催化还原速度差别增大若干倍。研究这一效应的本质表明,影像密度的提高是由于在传统显影液中不显影的小尺寸潜影中心的卤化银微晶也加入到照相显影过程之中的结果,它导致感光涂层的曝光区银量增加。根据研究结果,在医疗机构进行了应用试验,用于医用Ｘ射线胶片的加上,由于影像密度的增加,可显著降低Ｘ射线的照射剂量。     

非常规卤化银照相感光材料

非常规卤化银照相感光材料指的是与一般卤化银——明胶照相材料所用的原料,制备方法或加工过程不同,但仍属银盐系统的感光材料。这些材料中有不少在国外已经商品化,有的还处于科研阶段,但由于其独特的性能,很值得给予一定的重视。以下分别对这些非常规卤化银照相材料加以叙述。一、卤化银蒸发材料将溴化银干粉(或片状)置于蒸发皿中,加热熔融并使之在真空下蒸发,溴化银     

高感光度乳剂

本文介绍高内感光度卤化银乳剂组成和含化学增感卤化银内核及覆盖于此核上卤化银外壳乳剂构成的照相层。微粒卤化银与平均粒度较大又经化学增感的乳剂充分混合后可以制成一种粒度均匀的乳剂,并可再次进行化学增感。只要温度和时间适宜,混合后可制得表面感光度与灰     

One-photon processes of latent image formation in silver halides

Abstract

A new one-photon process for latent image formation in silver halides is proposed. The model is an extension of the theoretical concepts of Gurney-Mott, Hamilton and Lowe. Hamilton proposed a four-photon mechanism for the photochemical formation of Ag₄ latent image centres. Subsequently, Lowe developed a two-photon mechanism, which includes hole trapping by Ag₂ reduction centres. Mitchell proposed a two-photon mechanism based on the presence of electron trapping Ag₂ centres that act as sublatent image centres. One-photon latent image formation was proposed which relied on gold-containing electron-trapping centres; however, these mechanisms were considered to be fogging mechanisms. From the concepts of the previous mechanisms, a one-photon latent image mechanism is proposed that does not result in fog. This one-photon process is based on the presence of both electron and hole-trapping Ag₂ centres on the same crystal before exposure. Both photoelectron and photohole, which arc formed by light absorption, participate in this mechanism. The required electron-hole energy separation is estimated to be about 1.4 eV and is thus well above the thermal energy at room temperature (about 0.03 eV). Experimental evidence for one-photon processes in silver halide systems supports the proposed one-photon mechanism for Ag₄ latent image formation.     

Holographic optical elements recorded in silver halide sensitized gelatin emulsions. Part I. Transmission holographic optical elements

Silver halide sensitized gelatin (SHSG) holograms are similar to holograms recorded in dichromated gelatin (DCG), the main recording material for holographic optical elements (HOE's). The drawback of DCG is its low sensitivity and limited spectral response. Silver halide materials can be processed in such a way that the final hologram will have properties like a DCG hologram. Recently this technique has become more interesting since the introduction of new ultra-high-resolution silver halide emulsions. An optimized processing technique for transmission HOE's recorded in these materials is introduced. Diffraction efficiencies over 90% can be obtained for transmissive diffraction gratings. Understanding the importance of the selective hardening process has made it possible to obtain results similar to conventional DCG processing. The main advantage of the SHSG process is that high-sensitivity recording can be performed with laser wavelengths anywhere within the visible spectrum. This simplifies the manufacturing of high-quality, large-format HOE's.     

Holographic optical elements recorded in silver halide sensitized gelatin emulsions. Part 2. Reflection holographic optical elements

Silver halide sensitized gelatin (SHSG) holograms are similar to holograms recorded in dichromated gelatin (DCG), the main recording material for holographic optical elements (HOEs). The drawback of DCG is its low energetic sensitivity and limited spectral response. Silver halide materials can be processed in such away that the final hologram will have properties like a DCG hologram. Recently this technique has become more interesting since the introduction of new ultra-fine-grain silver halide (AgHal) emulsions. In particular, high spatial-frequency fringes associated with HOEs of the reflection type are difficult to construct when SHSG processing methods are employed. Therefore an optimized processing technique for reflection HOEs recorded in the new AgHal materials is introduced. Diffraction efficiencies over 90% can be obtained repeatably for reflection diffraction gratings. Understanding the importance of a selective hardening process has made it possible to obtain results similar to conventional DCG processing. The main advantage of the SHSG process is that high-sensitivity recording can be performed with laser wavelengths anywhere within the visible spectrum. This simplifies the manufacturing of high-quality, large-format HOEs, also including high-quality display holograms of the reflection type in both monochrome and full color.     

High Resolution Image Recording on Photosensitive Halide Layers

Thin layers of many halides and chalcogenides can be used for image recording since they decompose when illuminated, at a suitable temperature, with light that is absorbed in their fundamental absorption region. A review is given of this process and of the range of materials now available for ‘halide layer photography’. Potential applications of halide layers in image recording, holography and information storage are discussed in the light of recent experiments on the sensitivity, resolution, contrast and stability of the layers.     

The Search for Information

Thin layers of many halides and chalcogenides can be used for image recording since they decompose when illuminated, at a suitable temperature, with light that is absorbed in their fundamental absorption region. A review is given of this process and of the range of materials now available for ‘halide layer photography’. Potential applications of halide layers in image recording, holography and information storage are discussed in the light of recent experiments on the sensitivity, resolution, contrast and stability of the layers.     

卤化物钙钛矿射线探测器材料研究进展

卤化物钙钛矿由于具有高射线吸收系数、高载流子迁移率寿命乘积、可低温溶液法生长等特性,有望突破传统高纯锗和碲锌镉探测器在成本、芯片兼容性和大尺寸成像等方面的制约,成为新一代性能优异的室温射线探测材料。本文从卤化物钙钛矿材料的基本性质与射线探测原理出发,介绍了2015年以来卤化物钙钛矿射线探测材料与器件的发展历程;系统介绍了直接型射线探测器(强度、成像、能谱)及闪烁体探测器的最新研究成果;分析了材料特性与器件结构对射线探测器性能的影响机制,为今后更高效的卤化物钙钛矿射线探测器的开发提供参考。     

银盐照相与数码照相

本文探讨了传统银盐照相与数码照相的现状和发展前景。文中详细介绍了作为图像传感器的彩色胶卷和CCD(CMOS)的特性及其最新进展。尽管面对数码相机的严峻挑战，文章引用国际照相市场有关信息，预测传统彩色照相材料仍将会有缓慢的增长。一种融合传统银盐照相和数字成像两者特点的混合成像体系正在兴起。银盐照相与数字成像技术的融合，这将是21世纪成像技术的发展方向。     

Hybrid process of latent image formation in silver halide sensitized gelatin: differential hardening with microvoids

Renewed interest has been shown in the hybrid silver halide sensitized gelatin processes owing to the appearance of new photographic materials. In this study we show the possible compatibility between the models of latent image formation proposed prior to the existence of these new materials, bearing in mind that the refractive-index modulation and its curve of spectral response should be the figures of merit for optimization of the processes of transmission and reflection hologram formation.     

The Present Status of Photographic Sensitivity

Photographic sensitivity, an intrinsically practical concept related to the smallest exposure yielding a usable result, can be considered in various ways. For the photographic scientist it depends essentially on the formation of a stable latent image by the impact of a minimum of radiant energy and on its capacity to trigger the development reaction, while technical users of photography attempt to find means, however involved, for the extraction of the requested information from recordings unavoidably made unsatisfactory by the conditions prevailing during exposure.

As to the first approach, the principle of the absorption of at least four quanta per silver halide crystal to form a stable latent image, first demonstrated in 1960, is now quite generally accepted. The practical aspect of photographic sensitivity, on the other hand, is at present strongly influenced by the techniques of image evaluation and restoration, i.e. by pattern recognition and image processing. Ultimate sensitivity does indeed not only depend on the sheer presence of exposed and developed grains, but it is judged rather by the information transmitted to the observer by the recording.     

光化学成像体系与视频技术竞争的局限性

传统的光化学成像体系：银盐感光材料应用范围广泛，感光度，分辨率高，但实时性。非银盐感光材料具有实时性，分辨率极高。但大部分产品感光度极低。