Poster Sessions Presented at the International Symposium on Setting Quality Standards for the Forensic Community: Part 1 (Forensic Science Communications, July 1999)
October 1999 - Volume 1 - Number 3
Presented at the
2nd International Symposium on the
Forensic Examination of Questioned Documents
Albany, New York
June 14 – 18, 1999
ESDA Cascade Developer Awareness
M. H. Cavanaugh, B. L. Torres, and W. P. Grose
Los Angeles County Sheriff’s Department
Los Angeles, California
In the normal use of the electrostatic detection apparatus (ESDA), there are times when the toner residue seems faint when attempting to develop latent indented impressions. The typical action taken when this occurs is to cascade developer multiple times or to add additional toner to the glass cascade developer beads before continuing the process.
The surface of the cascade developer beads loses the ability to attract toner particles, reducing the effectiveness of the ESDA process. Over time the surface of the beads becomes roughened or pitted, which adversely affects their ability to hold a charge. With a reduced ability to attract toner particles, less toner material is available during the cascading process to develop the latent image.
Forensic document examiners should routinely check and replace cascade developer beads as necessary. A visual check, under magnification of 10X through 30X, can reveal the condition of the beads, which allows for a determination of whether the beads should be replaced (see examples in photos, below).
New beads: Most of the beads readily attract toner particles.
Used beads: Some of the beads show reduced ability to attract toner particles.
Old beads: Many of the beads lose the ability to readily attract toner particles.
Background information about the manufacture of cascade developer beads was provided by David Tobin (Foster and Freeman, Worcestershire, United Kingdom). He indicated that Foster and Freeman obtains new industrial grade glass beads from a local specialist glass supplier. The beads are made from fresh glass that is crushed to sub 4-mm size fragments and then fed into a rotating, heated drum. The drum is maintained at a temperature of approximately 600°C, which is hot enough to soften but not completely melt the glass fragments. The drum is also angled so that the glass fragments gradually tumble through it during the heating process, resulting in the formation of spherical beads. The glass beads are separated according to size by passing them over a series of graduated meshes. They are then checked for roundedness on a slowly revolving table, separated, and packaged for sale for use in casting and bead-blasting applications and for use with the ESDA.
After purchasing the manufactured beads, Foster and Freeman adds toner at a ratio of approximately 19 parts of beads to 1 part toner. This combination is mixed and then packaged in containers for market sales as cascade developer.
There was a dispute if a safe-deposit box lessor’s name was forged on records of entry into his safe-deposit box. The plaintiff, the executor of the estate, claimed the lessor’s name was forged and a large amount of cash was missing from the safe-deposit box. The safe-deposit box entry record (signature card) and several specimen signatures were submitted to a document examiner who rendered the opinion, “final signature is a forgery.” A second examiner reviewed the case, noted significant similarities, and requested additional exemplars as well as documentation of the lessor’s health on the date of the signature in question (December 23, 1992). The additional exemplars supported the significant similarities noted. The medical history stated the lessor had a history of acute gout and documented problems with his right (dominant) hand. The lessor’s medical file noted “Dec 23 1992 . . . pt states arm and rt wrist seems worse. pt states medication not helping . . . 0-red, swollen Rt. arm & wrist . . . arm sling.” The lessor died February 23, 1993. This poster presentation demonstrated the importance of requesting additional exemplars and the medical history when a case involves the writing of a deceased subject.Computer-Assisted Method for the Generation of Courtroom Charts for Presentations of Handwriting Evidence
S. G. Drexler
Alabama Department of Forensic Sciences
On many occasions the forensic document examiner must present the results of handwriting comparisons to judges and juries in clear, concise, and understandable terms. The most powerful means of illustration has been to create court displays that photographically depict a comparison of the questioned writing(s) to the characteristics of a known set of standard writings. Through the use of computer technology and commercially available scanners and software, this paper presents a new approach to this problem. This approach allows the analyst to use computerized scissors to cut and paste individual letters, letter combinations, and/or phrases to quickly produce high-quality charts for courtroom display and/or to incorporate graphic illustrations in technical reports for clarity.
The materials and equipment needed for this procedure are not expensive, unique, or difficult to operate: a personal computer with a Pentium® (Intel, Santa Clara, California) or equivalent processor, standard memory (at least 32 MB RAM), and imaging software such as Adobe Photoshop® (Adobe Systems Incorporated, San Jose, California) or Corel Draw® (Corel, Ottawa, Ontario, Canada). In addition, a flatbed scanner or video-frame grabber system such as Snappy® (Play Incorporated, Rancho Cordova, California) and a standard printer (300 dpi or better) are necessary.
Upon completion of laboratory analysis and comparison, examples of questioned and known writings are identified for illustration. If the known writings are verbatim in comparison to the questioned writings, examples of each can be chosen for imaging (see the questioned and known signatures shown below).
However, if the questioned and known writings are not verbatim and consist of various letter forms and letter and word combinations (see collected handwriting samples from a suspect, shown below right), a database of known writings must be compiled. Once completed, specific letters and letter combinations from the database can be merged into one document to form words and phrases that are verbatim to the questioned writings for a side-by-side comparison (see examples, bottom right).
Digital images of the writings chosen for illustrative purposes are either scanned or captured by a video-frame grabber. Although any image-capturing system should suffice, this author uses a flatbed scanner with the image-capturing features of Adobe Photoshop®. By adjusting the scan window, individual words, letters, and letter combinations can be captured. An additional tool incorporated into the Adobe Photoshop® software is the ability to de-emphasize or completely remove overlapping ink lines, rubber stamps, and obliterations. Once the desired images are captured, the author then uses Corel WordPerfect® (Corel, Ottawa, Ontario, Canada) to compose the illustrative document. Images from Adobe Photoshop® can be imported into WordPerfect®, moved in the document for proper placement, and proportionally enlarged or reduced to the desired size. Once the entire illustrative layout is completed, text can then be added for labeling purposes.
Questioned (top) and known (bottom) signature items.
Known handwriting standard from suspect.
Questioned signature (top) and handwriting standard composite “cut and paste” (bottom) created from the samples in the known handwriting standard from suspect.
The method uses computer imaging to perform the same task as standard photography followed by selective cutting and pasting. The method requires standard office computer equipment, software, and imaging peripherals. It is flexible, quick, simple to learn, and economical. Images can be included in case notes, laboratory reports, and enlarged and mounted on core board for courtroom presentations. And, just as with photography, if care is taken not to alter or distort original characteristics and detail, the final product will be factually correct.Method for Identifying a Signature Written
With the Intent to Deny Authorship
J. L. Hayes
James L. Hayes & Associates
Park Ridge, Illinois
The object of this study is to determine the authorship of a signature written with the intent to deny authorship. The questioned signature appeared on a loan document as a cosigner. The alleged author is a 60-year-old Certified Public Accountant (CPA) who knew the person requesting the loan. The Accountant denied signing the document, and the principal was not located. Handwriting standards were obtained from the Accountant which included dictated and ordinary course-of-business documents.
Previous testimony by the subject indicated that it was not an issue of forgetfulness. The subject stated he did not sign the loan guaranty. A factor to be considered was his professional standing as a CPA. Was it possible that the CPA felt the lending institution would not pursue a loan guarantor for a measly $10,000, especially when the questioned signature was apparently so different from the known standards (Conway 1959)?
The hypotheses that were considered in this case were necessary to arrive at a definitive determination. The questioned signature was not an attempt to imitate the known handwriting of the subject (Hilton 1982). As Osborn (1940) points out, it is the effort to copy exactly every feature and characteristic that fails the forger. This forger did not make that attempt.
Additional exemplars including dictated standards gradually revealed the characteristics necessary to piece together the foundation for an identification of the author of the questioned signature. The writer signed the questioned signature with the intent to deny authorship.
Methodology: Comparison and analyses of the questioned signature with extended exemplars.
The questioned signature did not appear to be a typical simulated forgery. Characteristics of the signature included a rapidly written line quality with nondistinct letter formations. Scientific Working Group for Questioned Document Guidelines were used in the reevaluation of this problem. The problem was approached with the following thoughts in mind:
- Most forgers make a diligent effort to create a signature that looks like the genuine writer’s signature. If the signature is not an attempt at simulation, could the observed characteristics be the natural writing of a third party?
- What are some of the common methods used to alter a signature?
Results: Based upon the examinations and comparisons, it was determined that
- The questioned signature was not a simulated forgery.
- It is extremely unlikely that another writer would have the same unique combination of characteristics as the genuine writer.
- The questioned signature was written by the known subject with the intent to deny authorship.
Conclusions: Categories of questioned signatures can be determined and when considered during the examination process, the information can be helpful in determining the identity of the author.
Opinion: The known subject signed his signature on the loan guaranty.
Conway, J. V. P. Evidential Documents. Charles C. Thomas, Springfield, Illinois, 1959, pp. 23, 96.
Hilton, O. Scientific Examination of Questioned Documents. Elsevier, New York, 1982, pp. 183.
Osborn, A. S. Questioned Documents. Boyd Printing, Albany, New York, 1940, pp. 273.Gambling With the Law
D. R. Howes
New York State Police Forensic Investigation Center
Albany, New York
An audit conducted by a New York gambling casino revealed that more winning pull-tab cards were being claimed than were printed. Four suspected fraudulent cards with a total win value of $15,000 (two for $5,000 and two for $2,500) were submitted for examination with one genuine win card.
Initial examination of the cards revealed that the submitted genuine $1 card and the three questioned $1 cards had the same serial number on their fronts. The manufacturer related that there were 76,000 cards with the same serial number, which is collectively called a deal. In each deal, there is a designated number of winners. The front of each card reveals the number of winners per deal by symbols and amount value.
Several nondestructive examinations were conducted on the genuine and questioned cards to determine if any distinguishing differences existed between the four questioned cards and the genuine card.
Several measurements of thickness were made in the area under the pull-tabs on each of the questioned cards and genuine card employing a paper micrometer. The thickness of the four questioned cards varied but was always greater than the thickness of the genuine card.
Ultraviolet light examination of the paper comprising the questioned and genuine cards was conducted employing the Foster & Freeman’s (Worcestershire, United Kingdom) video spectral comparator’s long-wave ultraviolet light source. This examination revealed a difference in the paper under the pull-tabs between the questioned and genuine cards. The paper on the four questioned cards exhibited a bright bluish-white fluorescence, whereas the paper of the genuine card had no fluorescence in the corresponding area.
A microscopic examination of the printed symbols under the pull-tabs of the questioned and genuine cards was conducted. At 90X magnification, the printed symbols on the four questioned cards exhibited characteristics of a similar printing process. The symbols on the genuine card exhibited an obviously different printing process.
The result of the examinations conducted on the submitted cards lead to one conclusion: The four questioned pull-tab cards had been altered and were fraudulent.
J. A. Jamieson
Virginia Division of Forensic Science
Relatively new types of printing inks that use high-intensity ultraviolet (UV) light to initiate the polymerization or cure of inks have been developed for the printing industry. These energy-curable inks are being utilized for most of the printing processes that questioned document examiners routinely examine. The UV-cured inks have been used in the lithography printing process for over ten years and have been widely used for flexography, silk screen, letter press, and gravure processes for less than five years.
Theory of UV-Cured Printing Inks
UV-cured inks contain a mixture of monomers, oligomers, photo initiators, coinitiators or synergists, sensitizers, pigments and/or dyes (if colored), and modifiers. The curing of the ink is best described as a photo-induced polymerization process.
The UV light induces the formation of free radicals in the photo initiator. The free radicals then combine with a monomer to form a reactive monomer. The reactive monomer can then take one of three paths. In the first reaction path, the reactive monomer can combine with another monomer to form a chain of two monomers. The chain of two monomers can then combine with another monomer to make a chain of three, and so on. The second path involves the smaller chains of monomers linking with the large chained oligomers. The oligomers can be thought of as the backbone of the growing polymer, and the smaller chains of reactive monomers serve to cross link the oligomers to form a complex, highly linked polymer. The monomers can link or bridge the oligomers together in any direction, and the length of cross-linking can be one or more monomers between the oligomers. The third path that the reactive-free radical on the monomer and the free radical itself can take is termination. The reaction ceases for that monomer. The polymerization process continues until all of the available reactive sites have been used up. The final UV-cured ink is basically one or several very large molecules with the pigment and unreacted components embedded in the large matrix. This can be visualized as a plum pudding with the UV-cured matrix as the dough, and the pigments and unreacted components as the raisins or fruit.
Samples of each ink (four-color process) were drawn down over paper or card stock in a controlled (laboratory) environment. The draw downs were cut into thin strips and reviewed for the various physical and solubility properties. Due to a lack of samples, only one color per test was performed. The use of the same color for each separate test was done to minimize the potential differences due to the coloring agents in the inks. The solvents were puddled from a dropper on the test strips, and the solubility was monitored for three minutes. At the end of three minutes, each test strip was swabbed with cotton and examined for ink degradation and dissolution.
Observations and Discussion on the Physical Properties of UV-Cured Inks
UV-cured inks have a characteristic odor likely due to the combination of photo initiators, coinitiators, and sensitizers that often use amine-type functional groups. The amines have a distinct odor that lasts for months.
UV-cured inks were not affected by either the ethanol/water mixture or by n-butanol. The other inks bled or dissolved to varying degrees.
UV-cured inks generally flake or chip off instead of dissolving like the other ink types. The UV ink has a characteristic residue of particles on the cotton swab that the other inks did not have.
Methods for distinguishing UV inks from the other inks include the following:
- Odor and gloss observations.
- Water application. The water-based inks are hydrophillic. The other three inks are not.
- Toluene application. The solvent-based ink will dissolve a great deal. The UV ink will develop small pinholes that may or may not be visible depending on the sample size.
- Cyclohexane application. The heat-set ink will bleed slightly. The water-based and UV inks will not be affected. The solvent-based ink will bleed moderately.
- Methylene Chloride application. The UV-cured ink will chip and flake. The solvent-based ink will bleed on contact. The water-based ink will bleed moderately. The heat-set ink will only slightly bleed (just stains the swab).
Unfortunately, due to the lack of samples and sample/substrate combinations, the path for absolute determination of UV-cured inks cannot be relied upon at this point.
UV-cured printing inks are relatively new to the printing industry. This paper presented an introduction to the theory of the curing mechanism for the UV inks as well as a preliminary method for the determination of the ink type using simple observations and solubility testing. Due to the limited sample size as well as the lack of numerous combinations and permutations of substrates, manufacturers, and pigments and dyes; the methodology for the determination of ink type is not an absolute practical routine and needs to be tested and repeated over the full-range of possible combinations.
The views expressed in this paper are those of the author and do not necessarily reflect the official policy or position of the Virginia Division of Forensic Science.Eradication of Impression Evidence: Part 2
Clarke Mercer Forensic Laboratory
The first phase of this project, Eradication of Impression Evidence: Part 1, was conducted by T. W. Welch, Michigan State Police, East Lansing, Michigan. The first phase was to determine if indented impression evidence can be eradicated by hand rubbing and if there would be evidence of that eradication. The second phase of the project took the same original evidence processed by Welch with an electrostatic detection apparatus and processed it again with a custom-designed instrument.
Materials and Methods
Each examiner employed their customary processing techniques, and a comparative analysis of the finished products was produced. The comparative analysis encompassed data related to the quality of the end product from two kinds of instruments, evidence of attempts to eradicate the impression evidence and how individual examiner techniques impacted the results.
The variables introduced into this phase of the testing included the following:
- Lower corona voltage output on the custom-designed instrument.
- Paper humidification for two minutes.
- Spritzer method (misting water over the developer container) with a back-and-forth transfer of the developer from one container to the other before cascading over the film.
- Lower volume of toner.
- Reverse processing.
Overall, the lifts produced in this phase of the project were better than those produced in the initial phase reported by Welch. In some instances the differences were dramatic. In others the differences were only minimal. The results emphasized the need to humidify the paper, use the spritzer method, employ a lower toner concentration when processing, and always use reverse processing. When Welch failed to obtain results, because of the rubbing process (friction/fats/oils/salts), the processing of both sides of the document with a lower toner concentration, produced evidence of the rubbing on the face with an acceptable visualization of the impressions and the reverse processing visualized the embossing to further enhance interpretation.