顯微分光光譜法對於印文蓋印時間之初探

The Application of Microspectrophotometry to Estimate Stamp Ink Dating-A Preliminary Study

吳旭恒(Shu-Heng Wu) ； 陳用佛(Yung-Fou Chen)

《國立臺灣博物館學刊》 67卷2期 (2014/06) Pp. 15-28

https://doi.org/10.6532/JNTM.2014.67(2).02

摘要

印文真偽的比對一直是我國文書鑑定上的大宗，對於印文蓋印時間的年代非破壞性分析更是一個有待突破的課題。顯微分光光譜儀（Micro-Spectrophotometer）是一種操作容易、非破壞性、適用於微物跡證的分析工具。對於具有顏色的微物跡證，可以顯微分光光譜儀來進行顏色的比對，測量其在某一波長領域內的吸收光譜，而達到比對、分析、甚至半定量的效果，對於同色異譜（Metamerism）的觀測提供了更客觀的數據。本研究主要係以顯微分光光譜儀分析國內常見之市售紅色印泥之可見光-近紅外光反射光譜，並檢視該樣品之光譜特性以及色度空間值（L*、a*、b*）隨著時間推移所產生的變化，以評估該非破壞性分析技術應用於印泥之年代鑑定的可行性。研究結果發現在穩定保存條件下，文件上所蓋印之紅色印泥出現顏色淡化的現象，造成L*隨時間上升；a*隨時間下降的現象，藉此可能可以做為印泥蓋印時間的參考。

關鍵字

顯微分光光譜儀 ； 年代分析 ； 印泥

並列摘要

The comparison of the authenticity of the sealed stamp ink text has been a large proportion in the questioned document examination (QDE) in Taiwan. For colored micro-objects tracing evidence, the Microspectrophotometry (MSP) can be applied to do color comparison and make the measurement in the absorption spectra within a certain wavelength; the comparison, analysis, or even semi-quantitative results can be achieved; for metamerism observations, it can provide more objective data. In this study, the MSP is mainly used to analyze the visible light- near infrared reflectance spectroscopy of the sealed stamp ink, which is domestic common commercially available. And then, view the spectral characteristics of the samples and chromaticity space values L*, a*, b*(L* is directly proportional with time, whereas a* is inversely proportional) with the changes produced by the passage of time.

並列關鍵字

microspectrophotometry (MSP) ； ink dating ； stamp ink

參考文獻

Aginsky, V.N.(1994).Determination of the age of ballpoint pen ink by gas and densitometric thin-layer chromatography.Journal of Chromatography.A678,119-125.

Brunelle, R.L.,Cantu, A.A.(1987).Critical evaluation of current ink dating techniques.Journal of Forensic Sciences.32,1522-1536.

Cantu, A.A.(1988).Comments on the accelerated aging of ink.Journal of Forensic Sciences.33,744-750.

Jeffrey, D.,Wilson, M.F.S.(2004).Differentiation of black gel ink using optical and chemical techniques.Journal of Forensic Sciences.49(2),364-370.

Kenneth, G.W.,Julie, A.H.,Bridget, M.,Aginsky, V.N.(1996).Dating and characterizing writing, stamp pad and jet printer inks by gas chromatography/mass spectrometry.International Journal of Forensic Document Examiners.2,103-116.