Nondestructive Differentiation of Full-Color Photocopies

Shiver, Farrell C.; Nelson, Larry K.

doi:10.1520/jfs13015j

Cited by 8 publications

(2 citation statements)

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“…Trzcinska, and Brozek-Mucha [9] removed toners physically and conducted the analysis by IR transmission on a microscope. The possibilities of toner analysis and classification by diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) have been described by other researchers [10,11,12,13,14,15] Bartick and Merrill [16] conducted studies using attenuated total reflectance (ATR) with a diamond internal reflection element (IRE) that was built into an FT-IR microscope objective. This method provided a completely nondestructive technique, because the toner remained on the document during the analysis.…”

Section: Introductionmentioning

confidence: 99%

Forensic discrimination of photocopy and printer toners I. The development of an infrared spectral library

Merrill

Bartick

Taylor³

2003

Analytical and Bioanalytical Chemistry

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Microscopical reflection-absorption by infrared spectroscopy (R-A IR) was shown as a viable technique for analyzing the polymer resins contained in dry, black photocopy and printer toners. The sampling technique involves a heat transfer of the toner from a document to the reflective surface of aluminum foil followed by analysis by R-A IR. The technique is simple, fast, and readily available to most forensic laboratories. A searchable spectral library was created that contains 807 toner samples analyzed by R-A IR. Ninety-eight groups were established based on spectral characteristics, and a flowchart was developed to assist with group assignments. A blind study was conducted to compare twenty photocopied documents each paired to a test document to determine if the pair could have been produced from the same copier. The analyst obtained 100% correct results in this study. Tests on thirty samples with the spectral library produced 90% first hits for the correct group. The three remaining samples were correctly determined by visual comparison of spectra for the top three hits. An actual case study was conducted where the investigation was narrowed from 400 possible machines to eight based on a comparative study of the photocopy toners.

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Section: Introductionmentioning

confidence: 99%

Forensic discrimination of photocopy and printer toners I. The development of an infrared spectral library

Merrill

Bartick

Taylor³

2003

Analytical and Bioanalytical Chemistry

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“…Williams [6] identified numerous resins and the pigment Prussian blue based on characteristic IR absorptions. The possibilities of toner analysis and classification by IR spectroscopy and by diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) have been described by other researchers [7,8,9,10,11,12,13,14]. Merrill et al [15] conducted a comparative study of three microscope-based IR techniques and DRIFTS for the analysis of toner samples.…”

Section: Introductionmentioning

confidence: 99%

Forensic discrimination of photocopy and printer toners II. Discriminant analysis applied to infrared reflection-absorption spectroscopy

Egan

Morgan

Bartick

et al. 2003

Analytical and Bioanalytical Chemistry

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Copy toner samples were analyzed using reflection-absorption infrared microscopy (R-A IR). The grouping of copy toners into distinguishable classes achieved by visual comparison and computer-assisted spectral matching was compared to that achieved by multivariate discriminant analysis. For a data set containing spectra of 430 copy toners, 90% (388/430) of the spectra were initially correctly grouped into the classifications previously established by spectral matching. Three groups of samples that did not classify well contained too few samples to allow reliable classification. Samples from two other pairs of groups were similar and often misclassified. Closer examination of spectra from these groups revealed discriminating features that could be used in separate discriminant analyses to improve classification. For one pair of groups, the classification accuracy improved to 91% (81/89) and 97% (28/29), for the two groups, respectively. The other pair of groups were completely distinguishable from one another. With these additional tests, multivariate discriminant analysis correctly classified 96% of the 430 R-A IR toner spectra into the toner groups found previously by spectral matching.

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Writing Instruments and Printing Devices

Sharfe¹

2009

Wiley Encyclopedia of Forensic Science

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This article is divided into two main sections. The first discusses the physical characteristics of the ink line of nib, ballpoint, porous tip, rollerball, and gel pens. Distinctive characteristics that allow their direction of stroke to be determined are also identified. The second section examines the image forming processes and characteristics associated with typewriters, dot matrix, laser, inkjet, and thermal printers. Identifying faults common to these printing processes are discussed from the view of comparing questioned documents to known printer outputs, which may lead to the identification of the specific printer as the source of the document under investigation. Identifying characteristics found in photocopiers and facsimile machines are also covered.

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Nondestructive Differentiation of Full-Color Photocopies

Cited by 8 publications

References 0 publications

Forensic discrimination of photocopy and printer toners I. The development of an infrared spectral library

Forensic discrimination of photocopy and printer toners I. The development of an infrared spectral library

Forensic discrimination of photocopy and printer toners II. Discriminant analysis applied to infrared reflection-absorption spectroscopy

Writing Instruments and Printing Devices

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