Author Abstracts: Wednesday, Sept. 21
Abstracts are listed in order of author presentations. Abstracts and the presentation schedule are subject to change; check this page regularly for additions and updates.
View Abstracts for Tuesday, Sept. 20 Presentations
Characterization of a Pink Discoloration from an Unusual Source
Brendan Nytes — Microtrace LLC
Of the many challenging and interesting cases received at our laboratory over the years, one type is uniquely difficult to identify. Discolorations, as they are described, are typically observed as a colored material on, or in, a contrasting matrix. Though these discolorations can be observed with the unaided eye, the compounds resulting in the coloration can be present at very low concentrations, which makes collecting data from these types of materials challenging. While in some cases, the materials can be identified specifically, the low concentration of analyte present in such samples can result in limitations to the extent to which the identity of the colorant can be constrained. In this presentation, the author will discuss their general approach to such questions through a case study that involved the characterization of a pink coloration that was observed on a white surface.
Environmental Factors Affecting Rapid Shear in Fibers from the Passage of a Bullet
Pete Diaczuk (presenting author), Laura Molina, and John A. Reffner — John Jay College of Criminal Justice, CUNY
In forensic casework, fabric defects can provide insight into the mechanism of the specific cause of the fiber failure. Different methods of fabric breakage impart differing physical characteristics on individual fibers. These alterations are determined by a multitude of factors, among them temperature. The process of rapid shear occurs in thermoplastic materials following high-speed impact. It results in distinct features caused by excessive heat generated through the interaction, which is unable to dissipate at a rate that would leave the fibers unchanged. Rapid shear characteristics can be differentiated from other fracture patterns through non-destructive microscopical methods and with a minimal sample size.
Fabric samples were shot with bullets under heated, chilled, and water-saturated conditions, using ammunition of varying velocities. Analyses performed on the defects were conducted using stereomicroscopy, polarized light microscopy, and scanning electron microscopy. Characteristics attributed specifically to rapid shear, specifically, globular-shaped fiber ends were observed in all nylon samples. Furthermore, loss of birefringence and changes in retardation were noted in these fibers in crossed polarized light. Through this study, it was discovered that the environmental conditions employed did not affect fiber end changes associated with rapid shear.
Image Only: Analysis When Sampling is Not Possible
Christopher S. Palenik — Microtrace LLC
Microscopists take pride in the amount of information that can be extracted from a minute sample. Many of the samples analyzed by microscopists can be collected in a manner that cannot be detected with the unaided eye, does not materially alter the original sample, or leaves ample material for further analyses behind. For this reason, microscopists, as well as attorneys and other stakeholders in the world of forensic science, have described these microscopical analyses as non-destructive. As in any attempt to describe something with language, the use of this term is not always interpreted consistently, since one might consider non-destructive to mean that nothing whatsoever was removed from a sample, while others would consider the same term to mean that a sample was not materially altered. While the terminology regarding the collection of a minute sample may be debated, there are also instances where case circumstances prohibit the collection of a physical sample. There are yet other circumstances where an image, but no sample, is all that remains.
Are there instances where enough information can be obtained from an image alone to address the question of a client? It depends. This talk aims to illustrate some of the ways in which our laboratory has provided probative information to clients even when the collection of a sample is not permitted or when a sample is no longer available. These analyses may come with limitations or caveats, but these examples will illustrate ways in which useful constraints can be placed upon the universe of possible answers to a client’s question. While there is no standard protocol for approaching such cases, a review of these examples will show that many of the same logical considerations that a microscopist applies to direct analyses of a sample remain applicable in such “image only” cases.
The Use of Microscopy and Spectroscopical Techniques in the Differentiation of Darkly Colored Automotive Carpet Fibers
Andra Lewis (presenting author), Geraldine Monjardez, and Patrick Buzzini — Department of Forensic Science, Sam Houston State University
Fibers from carpeting and rugs found in homes and vehicles are commonly recovered as evidence because they are easily transferred between the scene(s) and both the victim and suspect. Although most household carpet fibers are made of either nylon, polypropylene, or polyester, with differing cross-sectional shapes, automotive carpet fibers are made from a variety of substances. Due to demands to lower CO2 emissions by reducing vehicle weight, automotive carpet fibers are being made from lighter substances known as nonwovens. Many automotive carpet fibers are made from recycled polyester derived from plastic bottles as well as fibers which are blends of several types, including polyamides (nylon 6, nylon 6,6, etc.), polypropylene (PP), and polyester (PET), which can make the spectral analysis of these fibers challenging. Hence, 30 dark-colored and macroscopically similar automotive carpet fibers were analyzed using microscopical examinations including color assessment, cross-sectional shape, and fluorescence followed by UV-vis microspectrophotometry (MSP), μ-Raman and FTIR spectroscopy. The purpose was to determine the most efficient and non-destructive methodology for the application of spectroscopical techniques to the differentiation of darkly colored textile fibers that were indistinguishable after microscopical examination.
Never Too Small: A Microscopic Physical Fit
Jason Beckert — Microtrace LLC
Physical fits are well understood in forensic science and represent the highest level of association between a questioned and a known object. They occur when the irregular surfaces, or contours, of two objects correspond to each other, analogous to pieces of a puzzle. The finding of a physical fit demonstrates that two objects were originally joined together as a single object. In forensic science, physical fits are most commonly observed on macroscopic objects (e.g., a piece of mirror glass found at the scene of a hit-and-run which can be physically fit to remaining glass in the side view mirror of a suspected vehicle). However, the same principles can be applied to microscopic samples as well. This presentation will focus on the analysis of a pharmaceutical contaminant and how a microscopic physical fit provided insight into the mechanism of the particle’s formation and its deposition within the vial.
Development of Microscopical Methods for the Systematic Analysis of Chemically Reacted, Improvised Low Explosives and Related Residues: Project Update
Meggan King Dempsey — McCrone Research Institute
In January of 2020, McCrone Research Institute began a research project to use a microscopical approach to investigate the particles and residues resulting from a controlled burning and ashing of low explosives and related materials. The goal is to improve the comparison and analysis of unreacted, chemically reacted, and post-blast related residues and increase the overall understanding of the process and mechanism that may result in the inability to obtain analytical results from evidence. Extensive photomicrographs are being collected which will also serve as the starting point of an “Atlas of Charred Particles” at a future date. This presentation will discuss current progress and examine what is needed for project completion.
This project was supported by Award No. NIJ-2019-DU- BX-0047, awarded by the National Institute of Justice, Office of Justice Programs, U.S. Department of Justice.
Classification and Identification of Historical Inks
Jenna McConnell, Samantha Ottinger, Christopher S. Palenik (presenting author), and Skip Palenik — Microtrace LLC
Until the successful commercialization of ballpoint pens, the universe of writing inks was limited to a relatively small number of ink compositions, including iron gall, logwood, and carbon-based inks. Even within this limited population of ink formulas, hundreds of recipes existed. This variety began to expand with the introduction of synthetic dyestuffs, which were initially added to the historic inks as an additional colorant. It was not until the successful commercialization of “ball point” pens in the 1950s that ink compositions began to shift away from these traditional components. While there is a great deal of literature involving the analysis of pre-ballpoint writing inks, the practical identification of historical inks is not always as straightforward and clear-cut as presented in this literature. This presentation will provide a discussion of recent research conducted at our laboratory, which has focused on non-destructive classification and microanalysis of minute samples of historic inks. The non-destructive classification is based upon an examination of microscopical textures, trace elemental composition, and the response to a range of alternate light sources. Microanalytical characterization utilizes minute flecks of ink or millimeter sized document punch samples that are extracted and analyzed by ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry (UPLC-HRMS) to specifically identify organic colorants and mixtures of colorants in the historical samples of dried ink.
Forensic Authentication of a Purported Jackson Pollock Painting
Nicholas Petraco Sr.
This presentation will cover the forensic authentication of a painting known as “Untitled: Red, Black and Silver (RBS),” reported to have been painted by Jackson Pollock outside his studio in Springs, N.Y. for Ms. Ruth Kligman in the summer of 1956, three weeks before his tragic death. Included will be a review of scientific studies previously performed on the painting prior to the presenting author’s involvement, together with a detailed report of the trace evidence removed from RBS, its analysis and findings, and a brief review of the statistical evaluation of the trace evidence. In addition, the presenter will sum up the overwhelming circumstantial evidence, which in his opinion, proves conclusively that Pollock created the artwork in question at Springs.
Steps to Achieve Representative and Reproducible SEM-EDS Spectra in Paints and Polymers
Jack Hietpas (presenting author), Ethan Groves, and Christopher Palenik — Microtrace LLC
Paint and polymers are a common form of trace evidence because they can easily be transferred during the forcible contacts between objects and people. Scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS) is a well-established technique for the analysis of paint and polymer evidence. A review of the published scientific literature shows no study that addresses the requirements for sample preparation, instrumental conditions, or the size of the analyzed area needed, to collect reproducible and representative SEM-EDS spectra for vehicle paint samples.
The results from our research provide a framework to critically evaluate the potential spectral variability for paint and polymer samples that have different degrees of heterogeneity, e.g., number of phases, dispersal, and particle size distribution. The results demonstrate that polymer heterogeneity has a significant impact on the reproducibility and representativeness of the individual spectra. The results from this study provide guidance for selecting the size of the analytical area, number of counts needed in a spectrum, and number of spectra required to capture the within-layer variability for paint evidence. These data are anticipated to help caseworkers obtain more robust datasets that will ultimately assist with more critical interpretations of SEM-EDS spectra in the forensic comparison of paint and polymers.
One Thread at a Time: Microscopically Weaving Torn Paintings Back Together Using Thread-by-Thread Mending Techniques
Laura Eva Hartman — Dallas Museum of Art
Options available for repairing torn canvas paintings have evolved significantly in the last decade. Localized tear-mending techniques have grown in popularity as they allow the painting to remain as close as possible to how the artist intended and allow for minimal intervention to the original structure of the canvas support. Heiber or modified Heiber techniques are a particular type of structural treatment, done microscopically, one thread at a time, to bring the area as close to its original state prior to the damage. This means not only re-establishing the weave structure and tension, but also using materials that will react similarly to the original. Using a variety of tools, including McCrone precision microtools, this paper will reflect on the range of evolving options available for microscopic thread-by-thread mending techniques for torn canvas.
Secret of the Certificate
Joseph G. Barabe1 (presenting author), Thomas Phinney, and Walter Rantanen — 1Barabe & Associates LLC
Was this certificate, purported to be from about 1979, possibly authentic or a recent forgery? The certificate confirming the gift of a great art treasure from three loving daughters to their father was the singular piece of evidence arguing that the gifting had allegedly occurred. Multiple disciplines were brought to bear in the analysis, including printing process identification, paper analysis, forensic linguistics, and most importantly, font identification, including date and location of usage. This presentation will emphasize the effectiveness of a multidisciplinary approach to complex cases.
Iterations of Calcium Sulfate by Light Microscopy
Andrew A. “Tony” Havics — pH2, LLC
Calcium sulfate can be found in a number of locations, both naturally and anthropogenically formed. Naturally, it forms precipitated or eroded deposits, occurring with and without water in its structure. Its precipitation can result in massive deposits or in isolated crystals. Its most well- known iterations occur in drywall and plaster, with some sub-variations as well. The crystal habits and properties can vary depending on its history of formation, temperature of formation, additives or crystallization modifiers, and moisture conditions. A look at products, processes, applications, and material characterization reveals an opportunity to better understand and identify the crystal forms and transformations.
Judgment Day for the Vinland Map (1973 – 2021)
Gary J. Laughlin — McCrone Research Institute
In 1973, Walter C. and Lucy McCrone concluded that the Vinland Map was a forgery after extensive microscopical and microchemical analysis of the map and ink lines. They reported their findings in 1974 and never wavered on their discovery that the forger used a newly invented titanium dioxide pigment, patented in 1917. The finely divided sub-micrometer particles that comprised this “new” pale yellow pigment was first made available only during the 1920s. Shortly thereafter, the chemical process used to manufacturer titanium dioxide eliminated iron impurities, resulting in the pure-white pigment known today as titanium white or anatase, a relatively modern and now common inorganic pigment. In 1991, Dr. McCrone revisited the map to remove samples of the pale yellow ink lines in order to identify the organic medium in which the anatase pigment particles are dispersed and concluded that the ink medium is gelatin, i.e., a protein prepared from collagen.
In 1973, Walter and Lucy McCrone determined convincingly by light and electron microscopy, that the Vinland Map is a 20th century forgery. In 2002, Clark and Brown (University College London) determined with certainty by Raman microprobe spectroscopy that the Vinland Map is a 20th century forgery. In 2021, Lemay, Zyats, Bezur, Hark, Londero, and Wiggins (Yale) determined convincingly and with certainty, by macro X-ray fluorescence spectroscopy and Raman microspectroscopy that the Vinland Map is a 20th century forgery.
Conclusion: The Vinland Map is still a 20th century forgery.
View Abstracts for Tuesday, Sept. 20 Presentations