硝酸银、茚三酮、DFO法显现纸张上指印的效果比较

目的为有效的提高纸张上汗潜手印的显现率。方法根据汗潜手印的显现原理,针对不同的纸张,分别运用硝酸银、茚三酮与DFO（1,8-二氮芴-9-酮）3种显现方法进行了实验,并对实验结果进行了分析比较。重点分析了这3种方法在显现不同纸张、不同遗留时间、不同汗液量的汗潜手印时的效果及其适用范围。结果为改善渗透性客体上的汗潜手印显现效果,提供科学的依据。     

TFD-2纸张手印快速显现系统的应用

目的介绍一种利用特殊的红外热成像技术显现常见纸张上汗潜手印的新方法。方法利用英国Foster4-Freeman公司生产的TFD-2纸张手印快速显现系统,通过特殊的红外热成像技术,使汗潜手印呈现强烈荧光,从而显现手印。结果红外热成像方法处理后,汗潜手印在特种激发光（带宽为450nm-510nm）激发下显出较强的橙色荧光;持续处理后,汗潜手印在自然光下呈棕褐色,并在短波紫外光源（254nm）激发下也可显出清晰连贯的手印纹线;而且,新鲜和陈旧手印均有较好的显现效果。结论TFD-2纸张手印快速显现系统显现纸张上汗潜手印的方法,具有操作简单、快速安全、无需化学试剂、显现效果明显的特点,适合推广使用。     

纸张上手印的DFO-茚三酮-物理显影液系列显现方法研究

目的 提高纸张上手印显现率.方法 采用DFO-茚三酮-物理显影液系列显现法,比较每一显现步骤的指印显现率.结果 每一显现步骤均能提高手印显现率.结论 DFO-茚三酮-物理显影液系列显现法有效提高纸张上手印的显现率.     

防止茚三酮溶液扩散纸张字迹的研究

目的 解决茚三酮溶液在显现手印同时对纸张上字迹产生扩散作的问题;方法 分别采用茚三酮丙酮溶液,茚三酮氟利昂溶液,茚三酮石油谜溶液,茚三酮庚烷溶液作比较。结果 钢笔字迹用4种溶液均不易扩散;纸张上其它成份字迹用后两种方法显现手印时可有效保存纸张上文字原貌。     

手印固有荧光的检测

目的提高手印的成功率.方法用自然光、多波段光源对五种纸张上的汗液与油脂手印进行检验.结果470纳米下的固有荧光检测对手印显现非常有效.结论手印的固有荧光检测应作为手印显现标准程序的第一步.     

指甲花醌显现纸张上汗潜手印初步研究

目的介绍一种用天然植物提取成分指甲花醌显现渗透性纸张表面汗潜手印的方法。方法利用指甲花醌能够和手印遗留物质中的氨基酸发生显色反应来显现手印。结果显现出的手印纹线在自然光下观察呈紫褐色,并且在540nm激发光源条件下,通过红色护目镜观察还有很强的荧光特征。结论指甲花醌显现法具有安全性高、健康环保、操作简单、显现效果明显的特点。     

DMAC显现化学类纸张上汗潜手印的方法

目的找到一种显现化学类纸张上汗潜手印的有效方法。方法制作DMAC显现试剂并进行大量比对实验、外延实验。结论用该方法操作简便、效果较好。     

亮绿SF溶液增强红色光滑客体表面潜血手印技术研究

目的探索一种实验室和犯罪现场上均可使用的红色光滑表面上血潜手印新型显现技术。方法把0.2g亮绿SF溶解到容积为200m L盛有5m L蒸馏水的烧杯中,然后加入0.2g正四丁基碘化铵、93m L无水乙醇,使用玻璃棒搅拌,充分溶解后,最后加入盐酸2m L形成绿色透明溶液作为显现液,采用精细喷雾器喷涂客体增强红色光滑面潜血手印,潜血手印增强后,照相提取后并对局部放大观察效果,研究其对红色光滑表面潜血手印的增强效果。结果对遗留手印进行了批量显现与统计分析,0.2%的亮绿SF酒精显现液对红色客体表面潜血手印的反应极其敏感,实验室条件下潜血手印样本显现率可达100%,显出的手印纹线清晰连贯,反差明显,无颜色背景,且局部放大能够有效显示出纹线的细节特征。结论 0.2%的亮绿SF显现液能有效增强红色光滑客体表面潜血手印,反差极其明显,可以作为红色光滑客体表面潜血手印增强试剂。     

碘熏显现热敏纸上的汗潜手印

热敏纸作为一种特殊的客体,其传统显现普通纸张汗潜手印的显现方法,如(硝酸银显现法、茚三酮溶液法、DFO法等) ,都不能有效显现热敏纸上的汗潜手印。热敏纸遇到有机溶剂,药膜面上会产生黑色污染背景,影响指纹显现,甚至使整个膜面变黑,上面的手印消失。直接加热法显现热敏纸潜手印时,显现温度难以掌握,易污染检材,只能显现热敏纸膜面上的手印,背面的手印没法解决,对有效显现热敏纸上的手印有很大的局限。而碘熏法能克服上述不足,有效的显现热敏纸上的潜手印,此方法操作简便,显现效果较好,不仅能显现新鲜手印,还能显现保存较好的热敏纸上的…     

纸张上潜在手印三种前处理方法对DNA检验的影响

目的通过比较常见纸张上潜在手印盲提法与显现后精准提取法的接触DNA检出率,探讨常见纸张上接触DNA前处理的优选方案。方法比较五种常见纸张上使用盲提法和显现潜在手印(茚二酮显现法、茚三酮熏显法)后精准提取法采集的接触DNA样本检出率。结果粗糙日历纸盲提的接触DNA检出率为17.8%,通过茚二酮法和茚三酮法显现的潜在手印所提取的DNA检出率分别为75.6%、77.8%;光滑日历纸三种方法所提取的接触DNA检出率为4.4%、11.1%、11.1%;A4复印纸三种方法接触DNA检出率为20%、37.8%、66.7%;牛皮纸三种方法接触DNA检出率为20%、68.9%、64.4%;快递纸袋的三种方法接触DNA检出率为2.2%、6.7%、46.7%。结论不同纸张上潜在手印经显现后接触DNA检出率不同,通过茚二酮或茚三酮显示潜在手印后精准提取DNA的前处理方法相较于盲提法的接触DNA检出率高。实战中可应用此类方法同时获得手印与DNA分型,以有效提高证据力。     

Dating of Seals Produced with Stamp‐Pad Ink Using Gas Chromatography Method

Seals are often placed on important documents, and determining the date when a seal was affixed can be important to assess the authenticity of a document. In this study, thirty‐seven different brands of stamp‐pad inks and three different types of paper were used to make diachronic samples of the seals. The volatile components of stamp‐pad ink were determined, and the stamp‐pad ink was classified by gas chromatography with a flame ionization detector. Calibration curves were created to show the relationship between the content of volatile stamp‐pad ink components and the age of stamp‐pad ink entries stored under natural aging, UV‐induced aging, and heating aging conditions. The experimental results showed that GC was useful in the analysis of stamp‐pad ink and applicable for determining the relative age of stamp‐pad ink entries in some cases where the seal was placed on the document within 3 months.     

Preliminary Studies on the Absorbance Ratio Method Used to Determining the Age of Stamp‐pad Ink Seal

Stamp‐pad ink seals are often placed on important documents, and determining the dating of stamp‐pad ink seal is important to assess the authenticity of a document. In this study, 20 different brands and types of stamp‐pad inks were classified by ultraviolet visible spectrophotometer. Six different brands and types of papers were classified by micro‐Fourier transform infrared spectrometer and visual spectral comparator 6000. Three different brands of stamp‐pad inks and two different types of paper were used to make diachronic samples of the seals. A method was employed to date the stamp‐pad seals by comparing absorbance ratios and inks of known age. Curves were created to show the relationship between the absorbance ratio of ink and the age of the seals. The experimental results showed that the absorbance ratio method was applicable for the relative dating of stamp‐pad ink seals in some cases where the seal was placed on the document within 10 weeks.     

Application of Raman spectroscopy in forensic investigation of questioned documents involving stamp inks

Stamp pad inks from different manufacturers across India have been analyzed to investigate the feasibility of Raman scattering as a tool for forensic analysis of questioned documents involving stamp inks. Nine different stamping inks were analyzed by both Raman spectroscopic and HPTLC methods. The results demonstrate the effectiveness of these methods in classifying the investigated stamping inks based on their spectral pattern and HPTLC chromatogram. Raman scattering tool was able to determine the sequence of heterogeneous intersection strokes involving a blue stamp pad ink and other writing instruments, such as ballpoint pen ink (red and black), pencil and laser printer toner. However, this method was unable to resolve the exact sequencing for the intersection strokes involving investigated stamp ink and blue ballpoint ink or gel pen ink (all colors).     

Visualizing latent fingerprints on color-printed papers using ultraviolet fluorescence

Laser detection of latent fingerprints on a white paper has been performed, previously. Ultraviolet fluorescence from various kinds of printer toner and ink used for home printers were measured to study fluorescence imaging of fingerprints on a color-printed white paper. The experimental system consisted of a nanosecond pulsed tunable laser and a cooled CCD camera. Excitation wavelengths are 230 and 280 nm. Fourteen printers consisting of three color laser printers, three color inkjet printers, five monochrome laser printers, two monochrome copy machines, and a color copy machine were tested. Toner and ink of most printers exhibited fluorescence in the region from 360 to 550 nm. In most cases, clear fluorescence images were obtained by time-resolved imaging with a band-pass filter and 280-nm excitation. However for toners from laser color printers that showed strong fluorescence, better results were obtained with 230-nm excitation. Latent fingerprints on a photograph page and a black-character page of a newspaper were also imaged.     

油红O显现热敏纸上潜在手印研究

目的建立了一种油红O显现热敏纸上客体表面的潜手印的新方法。方法将检材浸泡在配制好的油红O的显现试剂中,油红可将指纹中遗留的油脂染色从而显现出手印纹线。结果显现出手印纹线为红色,纹线连贯,反差明显。结论油红O能够有效地显现出热敏纸上潜手印。     

高仿真制模伪造指印的识别研究

目的 探究高仿真制模伪造指印的识别方法.方法 选取多个印泥指印作为母版,分别采用曝光法制作指模,将母版指印与对应的伪造指印进行整体比较及显微比较.结果 伪造指印较母版指印尺寸存在差异、纹线略变粗、纹线间隔略变小、细节特征易黏连、细小痕迹及细微特征不反映或反映不全、单根纹线的墨迹分布平实且缺少细微漏白等.结论 识别伪造指...     

胶带粘面手印荧光显现剂的研发与应用

目的根据胶带粘面上潜在手印的特点,利用染料和潜手印的理化性质,研究开发胶带粘面手印荧光显现剂。方法在各种胶带粘面上显现潜在手印,并与常规的碳素墨水染色法进行比较。结果在长波紫外线照射下手印呈黄色明亮荧光,手印纹线清晰、连贯,基本不受手印遗留时间、客体表面颜色和性质的影响。结论胶带粘面上的汗潜手印和血潜手印用荧光显现剂显现效果优于碳素墨水染色法,在实际案件的侦破中有较好的应用前景。     

Determining the order of deposition of natural latent fingerprints and laser printed ink using chemical mapping with secondary ion mass spectrometry

Time-of-flight secondary ion mass spectrometry (ToF-SIMS) chemical mapping was used to investigate the order of deposition of natural latent fingerprints and laser printed ink on paper. This feasibility study shows that sodium, potassium and C₃H₅ positive ions were particularly abundant endogenous components of the natural fingerprints and also present in the paper examined, but were mostly absent in the laser printed ink. Mapping of these ions enables the observation of friction ridges from latent prints on the ink surface, only when a fingerprint was deposited above the layer of ink. As a demonstration of proof of concept, blind testing of 21 samples from three donors resulted in a 100% success rate. The sensitivity of this technique was investigated within this trial through the examination of up to fifth depletion fingerprints and ageing of up to 28 days. Migration of fingerprint and paper components to the ink surface, although observed with increased ageing time, was not found to compromise determination of the deposition sequence.     

尼罗红显现潮湿纸张上油脂手印方法初探

目的探索显现潮湿纸张表面油脂手印的显现方法。方法取250枚纸张载体的油脂指印,分为AB-CDE 5组,分别用自来水浸泡不同时间后,用尼罗红工作液显现,并在465nm多波段光源下进行观察。结果 5组的显现率从56%～94%,表明显出率比较高。结论该方法简单实用,可用于案件检验。     

文件上有色指印非纹线特征的应用研究

为了充分地发掘模糊指印形态特征在司法实践中的可用性和实用性,我们利用文件上有色指印的阶段性痕迹--墨迹边缘状态、积墨形态分布“、空白”形态分布及其相互位置关系等非纹线特征,分析研究了不同捺印人以油墨为介质连续捺印的样本指印50组共200枚,结果发现使用非纹线特征能够准确地分辨出同一手指连续捺印的同组指印。本文还对应用指印非纹线特征的各项技术要点进行了讨论,并且列举了该方法用于鉴定实践的三个成功案例。指印非纹线特征的应用不仅改变了对模糊指印只能出“具不具备鉴定条件”的结论模式,而且使适合使用该方法的被检指印形成相对时间的难题得到解决。