GCR分色工艺中黑版的确定方法

Determination Method of Black Printing Plate in GCR Process

中文关键词: 颜色转换  GCR  色彩管理  ICC

英文关键词: color conversion  GCR  color management  ICC

中文摘要:

      目的 解决预定义黑版不能依据图像原稿的油墨覆盖特征， 自适应确定黑版生成曲线的问题。方法 采用微观分析法研究中性灰色块网点的分布特征， 对比分析饱和色替代前后的色差情况。结果 黑版起点与加网线数和网点形状相关， 黑版起点位置的定义应以保护图像浅色阶调层次为原则， 实验中对于150 LPI传统网角的方形网点印刷， 黑版起点确定为13%的网点面积覆盖； 黑版曲线的幅度应在饱和色彩度最佳还原的基础上， 以最大黑版替代为原则， 以饱和色差控制在ΔE76小于3为依据。结论 在GCR分色工艺中， 以最大黑版替代为原则， 以饱和色差控制在ΔE76小于3为依据， 能使饱和色彩度保持的同时， 最大限度地节省彩色油墨用量， 确定的黑版替代曲线可用于指导建立设备链接特性文件， 以保证图像颜色转换更加准确。

英文摘要:

      The research aimed to solve the problem that the predefined black printing plate cannot adaptively determinate the black generation curve based on the characteristics of the original ink coverage. The distribution of neutral gray blocks was investigated using the microscopic analytical method to comparatively analyze the chromatic aberration before and after substitution of saturated colors. The starting point of the black printing plate was associated with the screen lines and the dot shape. The determination of the starting point of the black printing plate should be based on the principle of protecting the tonal level of light colors in images. In the experiment, the square dot printing with traditional 150 Lpi screen angle was adopted and the starting point of the black printing plate was determined to be 13% dot area coverage. And the black amplitude should be determined on the basis of optimal rendition of saturated colors and the principle of largest black substitution with reference of Δ E76 less than 3 for saturated aberration. In GCR process, the principle of largest black substitution with reference of ΔE76 less than 3 for saturated aberration can retain the saturated chroma, meanwhile, save the usage of color ink to the largest degree, and the determined black substitution curve can be used to guide the establishment of the device link profiles to ensure more accurate image color conversion.