显微分光光度法与显微红外光谱综合方法在黑色中性笔字迹鉴定中的应用

Identification of Different Black Gel Ink Pen Writings by Microscopic Spectrophotometry and FT-IR Microspectrometry

以黑色中性笔字迹为研究对象,共收集10个不同厂家不同型号的样本56份,结合化学计量学的方法对黑色字迹样本的显微红外谱图和显微分光谱图进行处理。对显微红外谱图进行聚类分析和相似度比较,以区分不同成分的字迹;利用聚类分析,可将56份样本中的47份按成分不同分为6大类;利用相似度的概念,可对谱图的差异性进行量化;显微分光谱图主要进行色差计算,以区分不同色度的字迹;利用色差计算公式,计算两样品间的色差,共得1596份色差数据,色差小于1的数据为31份,占全部比对样品的1.9%;将显微红外和显微分光分析结果进一步结合比对,可发现红外谱图聚为一类的样本之间有较大的色差,而色差很小的样本其红外谱图有较大差异,从而可将56份黑色字迹区分,为字迹的鉴定提供了新思路和新方法。

The identification of the component of the black gel ink pen writing was studied by using microscopic spectrophotometry（MiSP） and FT - IR microspeetrometry（ FT - IR MiS） combining with ehemometric methods. Fifty six black gel ink samples of different brands collected from 10 different factories were analysed by FT - IR MiS and MiSP, respectively. FT - IR spectra of 47 ink samples were selected and divided into 6 groups according to their different main components with clustering a- nalysis, while the differences of the spectra were quantified using the similarity concept. The MiS spectra were used for chromatic aberration calculation to distinguish the ehromaticiw of the writings. 1 596 data of chromatic aberration（AE） between each pair of samples were obtained and only 31 sam- ples whose chromaticities were less than 1. It was found that high AE was observed for samples with high similarity of FT - IR spectra, while smaller AE was observed for samples with low similarity of FT - IR spectra. Thereby, the black gel ink writing can be identified according to the above informa- tions.