Technical Link 技術鏈接

DIGITAL CAMERAS

With the advent of digital workflow in prepress and graphic communications industry, all the associated devices are undergoing a rapid evolution. And although much has been written about the impact that this has had on the output side of the process, dramatic changes are occurring on the input side as well. Digital cameras and scanners have become the popular image input devices and will completely replace those of old generation very soon.

Digital photography has started to replace scanning as a method of capturing photographs and is especially useful in catalog and product photography. Just as scanning can benefit from color characterization, so too can digital photography. Digital cameras present a challenge to characterize, however, because they involve more variables. In comparison to a scanner, a digital camera can be used with different light sources and captures the added dimension of depth. Color management of digital camera input is most useful in studio photography, where lighting and scene can be standardized.

An example of digital photograph: left - with color management; right - without color management.

Due to potential differences in the way they record color, each combination of camera (or camera back) and lights will probably need its own profile. If a “raw” digital photography produces color values that are much different than those of the characterization target, the color management program may not be able to make a color transformation that works. Therefore, the profile may need to be made with standardized adjustments in the operating software — for example, exposure, tone reproduction, and color balance.

Like a scanner operator, the digital photographer who wants to characterize input will need an IT8.7/2 reflective scanner characterization target, an accompanying IT8.7 data reference file of target measurements, and a color management program for making scanner profiles.

數字照相機

印前和印刷工業數碼流程的出現，使所有相關的設備正經歷著迅速的變革。盡管已經記述了許多有關影響工藝過程輸出方面的發展情況，然而在輸入方面也同樣發生了奇跡般的變化。數字照相機和掃描儀已經成為流行使用的影像輸入設備并且將很快完全取代老一代設備。

數字照相已經開始作為一種捕捉影像的方法來取代掃描，并且在樣本和產品照相中尤其有用。正如掃描可以從色彩特性化中受益一樣，數字照相也同樣如此。然而，數字照相機對特性化提出了挑戰，因為它涉及更多的變量。與掃描儀相比，數字照相機可使用不同的光源并且捕捉附加的景深范圍。數字照相機輸入的色彩管理在工作室攝影中最有用，這里的照明和場景可以標準化。

由于潛在的記錄色彩的方式不同，每種照相機（或照相機背板）與光源的組合也許將需要它本身的色彩特征。如果一個“原始”數字照相產生的色調值與特性化圖標相比有很大不同，那么色彩管理程序也許不能完成有效的色彩轉換。因而，色彩特征也許需要在操作軟件中經過標準化調節，例如曝光、色調復制以及色彩平衡。

與掃描儀操作者一樣，數字攝影師想要對輸入進行特性化時，要使用IT8.7/2反射掃描儀特性化圖標，一個附帶的圖標測量IT8.7數據參考文檔，以及用戶確定掃描儀色彩特征的色彩管理程序。