摄影.原始文件缩微胶片.ISO感光速度和ISO平均梯度的测定

[中文适用范围]： 本国际标准规定了一种确定黑白相机负片胶片的 ISO 速度和 ISO 平均梯度的方法，该胶片用于第一代源文档缩微胶卷，其曝光时间通常为钨光源。 这些源文档包括任何手写或打印的字母数字和行文档，例如书籍、期刊、商业信函和工程图纸。 本国际标准中描述的价值评级系统仅对消费者有用，如果消费者的曝光照明来自 5.3.3 中描述的白炽钨丝光源。 它不包括图像或连续色调再现、计算机输出缩微胶卷 (COM)、反转处理或直接正片或其他由非钨源（如激光或阴极射线管）曝光的胶片。 通过应用本国际标准获得的 ISO 速度和 ISO 平均梯度值旨在实际用于比较胶片/冲洗组合和计算曝光。 [外文原描述]： ISO 9848:2003 specifies a method for determining the ISO speed and ISO average gradient of black-and-white camera negative photographic films used for first generation microfilming of source documents at exposure times typically found with tungsten sources. These source documents include any handwritten or printed alphanumeric and line documents such as books, periodicals, business correspondence, and engineering drawings. The value-rating system described in this ISO 9848:2003 is only useful to the consumer if his exposure illumination is from an incandescent tungsten source. It is not intended to include pictorial or continuous tone reproduction, computer output microfilm (COM), reversal processed or direct positive films or other films exposed by non-tungsten sources such as laser or cathode ray tube. The ISO speed and ISO average gradient values obtained by applying this ISO 9848:2003 are intended for practical use in comparing film/process combinations and for computing exposures.