谈傅立叶红外图像系统法鉴别红色印油的种类

随着经济的发展,各种合同、证书的使用日益增多,对印油的鉴定愈显重要。关于印油的检验已有一些研究成果,但大都属于有损检验。找到一种简便快捷无损鉴定印油的方法,是很有必要的。采用Spotlight傅立叶变换红外图像系统的反射模式对14种不同品牌的红色印油所形成的印文样品进行直接测试,取得了满意结果,达到了区分不同产地、厂家的目的。该法快速、准确、客观并且不破坏样品。     

An examination of handwritten signatures forged using photosensitive signature stamp

Signature examination is the most common examination performed by any document examiner. Determination of the authenticity of a handwritten signature on a questioned document is an important task for forensic document examiners in the forensic science field. As a result of continuous developments in technology, a signature stamp can now be created using a photosensitive seal to enable the reproduction of a handwritten signature. These stamps are commonly used in China and several other countries. In this study, 10 types of black photosensitive stamp-pad ink, 10 brands of fountain pen ink, 15 types of black gel ink and six types of black erasable gel ink found on the Chinese domestic market were collected and 10 photosensitive signature stamps were created using the signatures of 10 people. Microscopic analysis, infrared (IR) and fluorescence analyses and microspectrophotometry (MSP) techniques were used to examine the resulting photosensitive signature stamp impressions when applied to printing papers, writing papers and invoice papers. By comparing the printing and spectral characteristics of the photosensitive signature stamp impressions with those of the signatures executed using the fountain pens, gel pens and erasable gel pens, it was possible to determine whether each signature was written or stamped using a photosensitive signature stamp. To validate these results, a 96.7% absolute accuracy and a 99.3% detection rate were achieved over a total of 150 blind tests conducted by five forensic document examiners, thus demonstrating that a combination of the four analysis methods used in this work can provide a more scientific approach and improve the accuracy and the detection rate of the examination process.

KEY POINTS

• A signature stamp is a photosensitive seal made in the style of a handwritten signature.
• Although microscopic analysis can usually provide better examination results, a comprehensive examination method that includes microscopic analysis and ink composition analysis is required to improve the accuracy and the detection rate of the examination process.
• This study collected and tested photosensitive stamp-pad inks, fountain pen inks, gel inks and erasable inks.
• Infrared and fluorescence analyses and microspectrophotometry were able to distinguish the photosensitive ink from both erasable ink and fountain pen ink.

Supplemental data for this article are available online at https://doi.org/10.1080/20961790.2021.1898755.     

数码相机在痕迹物证照相中的应用

痕迹物证照相是痕迹检验的重要一环。使用数码相机进行物证照相,痕迹检验人员可以根据需要自行拍照曾经由专业技术人员拍照的物证相片,这对于提高检验效率和检验质量具有重要意义。本文从基层痕迹检验技术人员的角度出发,着重研究如何使用消费级的数码相机拍照微小的痕迹物证。