Theory of Subtractive Color PhotographyIII. Four-Color Processes and the Black Printer*
Theory of Subtractive Color PhotographyIII. Four-Color Processes and the Black Printer*
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减色摄影理论III．
DOI：
10.1364/josa.30.000322
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发表时间：
1940
期刊：
影响因子：
--
通讯作者：
J. Yule
中科院分区：
文献类型：
--
作者：
J. Yule
描述了两种主要类型的黑色打印机——(a)黑色打印机仅用于增加最大密度；(b)再现的全部灰色成分由黑色提供的那些。为了实际的目的，黑色打印机的密度应该是一个函数的最低等效密度的三个图像组件，当后者是色彩校正，以提供一个准确的三色再现。介绍了几种理论上可行但有些复杂的选择三种密度中最低密度的方法。红外线辐射的使用是目前已知的制造一台好的黑色打印机的唯一方法，但它的应用受到限制，因为它依赖于视觉和红外线亮度之间偶然或人为引入的关系。为了准确地呈现亮度，色彩校正后的三色分色需要借助黑色打印机掩模进一步校正。
Two main types of black printer are described—(a) those in which the black printer is only used to increase maximum density; (b) those in which the total gray component of the reproduction is supplied by the black. For practical purposes, the black printer density should be a function of the lowest of the equivalent densities of the three image components when the latter are color-corrected to give an accurate three-color reproduction. Several theoretically possible but somewhat complicated methods of selecting the lowest of three densities are described. The use of infra-red radiation, which is the only previously known method of making a good black printer, is limited in its application, since it depends on accidental or artificially introduced relationships between visual and infra-red brightness. For accurate brightness rendering, the color-corrected three-color separations require further correction by means of a black printer mask.