tailieunhanh - Hazardous Industrial Waste Treatment - Chapter 9

Một vật liệu nhiếp ảnh bao gồm một cơ sở của một tờ của bộ phim nhựa, thủy tinh, hoặc giấy tráng với một nhũ tương nhiếp ảnh (bao gồm một loại vật liệu cao phân tử như gelatin có chứa rất nhiều tinh thể Phạt tiền bạc halogenua nhạy cảm ánh sáng). Bạc halogenua sử dụng trong nhũ tương nhiếp ảnh bao gồm bạc bromua, clorua bạc, bạc iodide, hoặc hỗn hợp của những. Tiếp xúc của nhũ tương ảnh này kết quả ánh sáng trong sự hình thành của một "hình ảnh tiềm ẩn", một bốn-ten nguyên tử. | 9 Treatment of Photographic Processing Wastes Thomas W. Bober Dominick Vacco Thomas J. Dagon and Harvey E. Fowler Eastman Kodak Company Rochester New York . THE PHOTOGRAPHIC PROCESS Exposure A photographic material consists of a base made of a sheet of plastic film glass or paper coated with a photographic emulsion consisting of a polymeric material such as gelatin containing numerous fine crystals of light-sensitive silver halide . Silver halides used in photographic emulsions include silver bromide silver chloride silver iodide or mixtures of these. Exposure of this photographic emulsion to light results in the formation of a latent image a four-to-ten atom speck of metallic silver on the silver halide crystal. In simplified terms light striking molecules of silver halide AgX in the emulsion causes some of them to be reduced to metallic silver Ag0 atoms. This can be represented by the following simplified equation AgX light . 1 silver halide metallic silver latent image This latent image is invisible to the naked eye because it consists of only a minute portion of the total amount of silver halide available in the emulsion. The number of atoms converted to silver depends on the intensity of the light and the duration time of exposure as well as several other factors not discussed here. The following discussion of development covers black and white images. Color development is examined in a later section. See additional references 1-4 for a more complete description of the photographic process. Development In order to be useful this nearly invisible latent image must be enhanced or amplified by converting other surrounding silver halide molecules to silver metal until the metallic image becomes fully visible. This is done chemically by a process step known as development. The latent image is developed by immersing the emulsion into a solution the developer containing a Retired. 361 2007 by Taylor Francis Group LLC 362 Bober et al. mild .