頻譜分析模式應用於判別紙張螢光特性之研究

在數位典藏中常使用色彩複製技術為進行影像記錄與保存，然而市售印刷紙張為了讓外觀白淨，在製造過程中添加了螢光增白劑（OBA, Fluorescent Brightening Agent），使紙張頻譜反射光譜中增添藍光波段，造成人眼覺得紙張更白的感覺，但隨著紙張長時間接觸空氣或光照，螢光增白劑逐漸失去效果而使紙張顯露出原本的色彩，間接影響了印刷在其上的色彩。因此在印刷前，確定紙張不含螢光增白劑後才用於印刷複製品格外重要，免去螢光增白劑失去活性的問題外，也能使典藏作品的色彩更加穩定。傳統螢光增白劑檢測的方式為使用UV紫外光（Ultraviolet）燈箱下照射並觀測是否產生螢光，但長時間的曝露於UV紫外光下也會造成研究人員視覺系統的傷害，因此本實驗嘗試使用多頻譜分析模式取代UV紫外光（Ultraviolet），除了可以大幅減少檢測過程中曝露在UV紫外光的時間，也達到數值化記錄螢光增白劑含量的功能，比起照射UV紫外光完全依靠肉眼觀測發光程度，更能精確比較紙張彼此之間的差異。

關鍵字

螢光增白劑； UV紫外光；多頻譜

並列摘要

Color reproduction technique is a common method in digital archive to generate objects' image data. Therefore, a stable reproduction process, for example printing image on paper, is needed. However, optical brightening agent (OBA) is often added to make inkjet paper whiter, which affects the spectral property of the paper and increases blue band intensity. The continued exposure on air or light would reduce the effect of OBA and then let paper return to its original yellowish color which indirectly affects the color appearance on printings. Consequently, make sure that the inkjet paper not included OBA is an important matter before high quality ink-jet printing. But constant exposure to UV also might hurt observers' eyes. The study explores the possibility to use spectral technique to detect the OBA on ink jet paper.