英语翻译STOCHASTIC SCREENING:WHAT TO DO WHEN YOUR RIP DOESN’T SU

英语翻译
STOCHASTIC SCREENING:WHAT TO DO WHEN YOUR RIP DOESN’T SUPPORT IT AND COMPARISON WITH CONVENTIONAL SCREENING ON AN OFFSET PRESS
Abstract:
Amplitude modulated (AM),or halftone,screens place varying sized dots in exact locations to simulate a continuous tone image.In contrast,frequency modulated (FM),or stochastic screens,place identical sized dots in a random pattern to simulate a continuous tone image.This paper compares AM and FM screens on the same press sheets from the same set of plates on an Offset printing press.The AM screens were produced using standard RIP settings on an AGFA ProSet 9550 Image setter,while the FM screens were produced using the "diffusion dither" option in Photoshop prior to sending to the RIP.In order to achieve a meaningful comparison of images printed by the different screening methods,we developed a set of cutback curves for the black ink to obtain "zero" apparent Tone Value Increase (dot gain) on press for each screening method.These curves were then applied to all four colors in the 4-color press run.Colorimetric measurements showed good agreement between the two screening methods.Dot fidelity analysis showed that viable dots were obtained with either screening method,but that significant Tone Value Increase (TVI) occurred from film to plate and from plate to press with either screening method.The independent cutbacks to zero apparent TVI were required since the actual TVI was different for the two screening methods.
Introduction:
AM and FM screening take two totally different approaches to generating dithering patterns for reproducing a continuous tone image (Fischer 1989,Schlapfer 1994,Tritton 1996,Chung 1997 and Scheuter 1985).AM screening is another name for the conventional method of generating digital halftones.It breaks up an image into dots of varying sizes and precisely centered on a rectangular grid to simulate the original (usually photographic) image.In order to produce a four color image using AM screening,varying screen angles are generally applied to cyan,magenta,yellow,and black (CMYK) to avoid printing identical grids on top of one another and producing objectionable moiré patterns (Yuasa 1994).Further more,there is always a physical and mathematical relationship between number of gray levels,the resolution of the imaging device and the screen ruling,such that there is always a tradeoff between resolution and number of reproducible grayvalues (Scheuter 1985).

随机检查:当你做扯裂好像比常规检查和支持在抵销出版社 摘要:Modulated调幅(AM)、半音,屏幕大小不同地点的确切位置,圆点不断模拟及形象.与此相反,频率调制(FM)或随机屏幕,把大小相同的随机圆点模式模拟及持续的形象.这份文件时,外交部与新闻报道在同一屏幕的同一套以弥补印刷板.在制作时使用标准屏幕扯裂环境形象在9550年制定PROSet转换,制作屏幕调频用"勇敢推广"的办法,把以前的Photoshop扯裂.为了实现有意义的比较影像印的不同检查方式,我们制订了一套削减曲线的黑色墨水获得"零"显然语气价值增加(部获得)出版社每次放映Method.theseCurves当时适用于所有四种颜色的四色印刷.比色测定结果好协议筛选Methods.dot富达分析显示可行圆点获得与任何筛选方法,但重要的基调价值增加(有限)发生在电影板块和板块向新闻界提供任何甄别Method.the独立削减为零显然有限必须从实际有限不同的两种检查方法.介绍:放映时,外交部采取两种完全不同的方法来创造一个持续徘徊模式复制及形象(菲舍尔1989年Schlapfer1994年Tritton1996年和1997年中Scheuter1985).放映时是同义词数码halftones传统发电方式.它碎裂成圆点的大小和形象,正是围绕着一个长方形的原模拟网(通常摄影)形象.为了制作用四色图像放映时,不同的角度上,一般采用印刷、食品、黄、黑(红)以避免相同印刷网之上,彼此产生不良moiré模式(汤1994).还有,有一定的数学和物理的关系格雷多层次、解决成像仪屏幕和执政,因此始终存在着交换关系,解决一些grayvalues再现(Scheuter1985).