Sulfur sensitization

Japanese: 硫黄増感 - いおうぞうかん

...Chemical sensitization is used to increase photographic sensitivity without changing the wavelength range of sensitivity by adding a sensitizer to the emulsion and heating and stirring it to introduce a small amount of impurities onto the grain surface. Silver sulfide and gold ions are particularly effective impurities for increasing sensitivity, and are called sulfur sensitization and gold sensitization, respectively. Silver halide grains themselves are sensitive to light from the ultraviolet range to blue light, but spectral sensitization is used to adsorb a sensitizing dye onto the silver halide grains, sensitizing the silver halide grains through the light absorption of the sensitizing dye, expanding the wavelength range of sensitivity of the photographic emulsion to longer wavelengths or to sensitize to a specified wavelength. ...

From [Sensitization]

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[Chemical sensitization]
When a sensitizer is added to a photographic emulsion and it is ripened, the silver halide crystals in the emulsion react chemically with the sensitizer to create sensitization nuclei in the crystals. Depending on the sensitizer used, there are sulfur sensitization, reduction sensitization, and gold sensitization. Sulfur sensitization is a sensitization method in which trace amounts of sodium thiosulfate and organic sulfur compounds are added to the emulsion, and it is thought that silver sulfide is formed in the silver halide crystals, improving the efficiency of the exposure process.

*Some of the terminology that refers to "sulfur sensitization" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

Japanese:

…化学増感は，乳剤に増感剤を添加して加熱かくはんすることにより粒子表面に微量の不純物を導入し，感光波長域を変えずに写真感度を増加させるために用いられる。感度を増加させる不純物としては，硫化銀と金イオンがとくに有効であり，それぞれ硫黄増感および金増感と呼ばれている。ハロゲン化銀粒子自身は紫外域から青色光にまで感光するが，分光増感はハロゲン化銀粒子に増感色素を吸着させ，増感色素の光吸収によりハロゲン化銀粒子を感光させ，写真乳剤の感光波長域を長波長側に拡大したり，所定の波長で感光させるようにするために用いられる。…

【増感】より

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［化学増感chemical sensitization］
　写真乳剤に増感剤を加えて熟成すると，乳剤中のハロゲン化銀結晶は増感剤と化学反応を起こして結晶中に増感核を作る。用いる増感剤によって硫黄増感，還元増感および金増感がある。硫黄増感は乳剤に微量のチオ硫酸ナトリウム，有機硫黄化合物を加える増感法で，ハロゲン化銀結晶に硫化銀が生成して感光過程の効率をよくすると考えられる。…

※「硫黄増感」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典第２版について | 情報

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