2026 Abstracts and Presentation Schedule
Abstracts are listed in order of author presentations for Tuesday, June 16 and Wednesday, June 17, 2026. The presentation schedule is subject to change; check this page regularly for updates.
TUESDAY, JUNE 16
TUESDAY MORNING
The Microscopist Who Gave US the Nucleus— Video Presentation
Brian J. Ford
The Scottish botanist Robert Brown was one of the most accomplished microscopists of the 1800s. Working with exquisitely crafted single-lensed microscopes 200 years ago, he documented the cell nucleus, studied the naked ovule of gymnosperms, and launched the study of what we now call Brownian Motion. In this presentation, Brian J. Ford reveals the fascinating story of Brown's microscopes.
Pan Handling Minerals: Evaluating Water-Driven Panning as an Alternative to Heavy Liquid Separation
John Palenik — Microtrace LLC
Most of the world’s sands are made up of “light” silicates, such as quartz and feldspars. Because of their frequency and abundance, these minerals are generally less characteristic of a sand’s identity than heavier minerals. Separating sand samples into heavy and light mineral fractions then becomes an important preparatory step towards sand characterization, such as geo-sourcing analysis. The standard process of heavy liquid separation (HLS) is effective but limited to a laboratory environment, since the chemicals used in this process (e.g. bromoform) are difficult to obtain, expensive, and bad for the environment. In this project, the technique of water-driven panning was explored as an alternative method for isolating heavy minerals.
Samples of beach sand were collected, processed, and analyzed to determine the effectiveness of this panning technique. These included control samples, fully and partially panned sands (including magnetically separated samples), and heavy mineral deposits. Particle counts of 1,000 grains of sand from each of the samples were conducted, logging the numbers of light minerals, heavy-transparent minerals, and heavy-opaque minerals, in each sample. Individual minerals were characterized through a combination of polarized light microscopy and microchemical tests.
The results showed that compared to the control samples, panning dramatically reduced the abundance of light minerals and greatly concentrated heavy minerals. It was thus demonstrated that water-driven panning could be a cheap, effective, and environmentally friendly field tool for preparing sands for analysis.
Concrete Analysis Using Polished Thin Sections
Laura J. Powers — YA Engineering Services
Concrete is the most widely used engineered material in the world. When it does not perform as designed, petrographers are engaged to investigate the possible cause. These investigations, codified in ASTM C856, normally employ polarized-light microscopical examination of thin sections to assess composition and microstructure. The diagnosis of many distress and degradation mechanisms, that affect concrete, benefits from additional investigation by scanning electron microscopy coupled with energy dispersive x-ray spectroscopy (SEM-EDS). SEM-EDS for this purpose, has been integrated into concrete petrography and codified in ASTM standard C1723.
Specimens for petrographic microscopy and SEM-EDS analysis are prepared from areas that will yield the most information pertinent to the investigation. Thin sections are prepared for polarized-light microscopy and thick polished sections (pucks or slabs) are prepared for SEM-EDS. Polished thin sections are used when both petrographic microscopy and SEM-EDS are required. These preparations allow the same features to be observed using transmitted light, reflected light, fluorescence, backscattered electron imaging, and EDS analysis. Polished thin sections are more difficult to produce and should be protected from exposure to air and moisture. This presentation discusses the preparation of polished thin sections and their application in concrete petrography.
From the Blast to the Microscope: Detection of Organic Explosive Residues Using Micro-Raman Spectroscopy
Geraldine Monjardez (presenting author) — Department of Forensic Science, College of Criminal Justice, Sam Houston State University, Huntsville, TX, and Jared Estévanes — Microtrace LLC
This study aims to develop a workflow involving a simple liquid extraction for the rapid and accurate identification of smokeless powder components, TNT, and RDX post-blast explosive residues using micro-Raman spectroscopy. Four simulated IEDs were constructed using various substrates to mimic components commonly found in IEDs. Two devices utilized smokeless powder as the main charge, while the remaining two used a TNT/RDX mixture. The substrates were sampled with pre-wetted acetone swabs, taking care to avoid collecting any unburned particles. The swabs were then soaked in acetone for three minutes to extract the analytes. A 10 µL drop of the extract was then placed onto a steel microscope slide and allowed to dry before being analyzed with the Raman microscope, alongside a standard reference mixture containing 50 ppm each of ethyl centralite, dibutyl phthalate, diphenylamine, and nitroglycerin in acetone. From the smokeless powder IEDs, components including ethyl centralite, dibutyl phthalate, diphenylamine, and nitroglycerin were detected on all sampled post-blast substrates except the wooden paint sticks. While TNT and RDX were not detected in the first detonation, TNT residues were successfully identified in the second. Additionally, crystalline material observed in the dried TNT/RDX extracts displayed Raman spectral features consistent with RDX.
Polarized Light Microscopy and Microanalysis of Tableting Mixtures
Andrew Bowen — U.S. Postal Inspection Service
One of the trends observed by the seized-drug community over the past couple decades has been the rise in illicit and counterfeit pressed tablets. Tablet presses and dies can be purchased through on-line marketplaces, whole or in parts to be assembled separately. Ready-to-use tableting mixtures are also available from a variety of on-line vendors, including from manufacturers in foreign countries.
Numerous bags of tableting powders from an apparent illicit tableting operation were submitted to the U.S. Postal Inspection Service National Forensic Laboratory for analysis. The laboratory request included the identification of non-controlled substances in suspected tableting mixtures to provide evidence of the intent to produce illicit tablets. A wide variety of organic and inorganic inactive ingredients were identified in the tableting powder mixtures, including some surprising components.
Given the nature of the mixtures encountered, polarized light microscopy was particularly well-suited to determine the powder compositions. The results of the analysis of these tableting powder mixtures will be discussed in detail during the presentation, which will highlight the important role that polarized light microscopy played in the examination.
Numerous bags of tableting powders from an apparent illicit tableting operation were submitted to the U.S. Postal Inspection Service National Forensic Laboratory for analysis. The laboratory request included the identification of non-controlled substances in suspected tableting mixtures to provide evidence of the intent to produce illicit tablets. A wide variety of organic and inorganic inactive ingredients were identified in the tableting powder mixtures, including some surprising components.
Given the nature of the mixtures encountered, polarized light microscopy was particularly well-suited to determine the powder compositions. The results of the analysis of these tableting powder mixtures will be discussed in detail during the presentation, which will highlight the important role that polarized light microscopy played in the examination.
Evaluation of Dispersion Staining Color Determinations Across a Number of Microscope Optical Configurations by Observers and Micro-Spectrophotometry
Antonio Del Valle (presenting author) and Thomas A. Kubic, John Jay College of Criminal Justice, CUNY
This study, by two authors of prior work presented at Inter/Micro 2025 (1), further expands on exploring the application of microspectrophotometry to dispersion staining analysis. In this work, we continue the use of an Ocean Optics USB2000+ microspectrophotometer (MSP) for the precise measurement of wavelengths associated with dispersion staining colors. Measurements were conducted using a range and combination of optical configurations, including low- and medium-power microscope objectives from LOMO (9× and 25×) and Olympus (10× and 20×), in conjunction with various condenser setups, including a number of condensers with various darkfield microscopy stops.
We present a comparative analysis of annular stop dispersion staining colors (ASDS), central stop dispersion staining colors (CSDS), and central stop–equivalent colors as described by Clarke (2, 3). Color determinations were assessed both subjectively, through visual observation by microscopists, and (hopefully) more objectively, through MSP-based spectral measurements. Additionally, comparison with the McCrone Dispersion Staining Color Chart demonstrated close agreement between observed and measured colors.
1. Kubic, T.A., Miranda, M., and Del Valle, A. “Variation of Dispersion Staining Colors Observed by Analysts with Different Experience Levels and Other Points of Variation” Inter/Micro Symposium, Chicago, June 11, 2025.2. Clarke, T.M. “Rediscovery of Darkfield Dispersion Staining while Building a Universal Student Microscope” Microscopy Today, 11:1 pp. 24–28, 2003.
3. Clarke, T.M., (2009) “Dispersion Staining Using a 1.2-1.3 NA Cardioid Darkfield Condenser” The Microscope, 57:4, pp. 147–152, 2009.
TBA
Christopher Palenik — Microtrace LLC
Differential Central Mask Illumination (DCMI): A Tunable, Non-Interferometric Phase-Gradient Contrast Method
William A. Mark — Haleon
Differential Central Mask Illumination (DCMI) is a non-interferometric method for generating directional phase-gradient contrast in transmitted-light microscopy. The technique combines circular oblique illumination (COL), polarization, and a birefringent step-wedge retarder to produce controlled asymmetry in the objective back focal plane. This asymmetric pupil configuration converts specimen phase gradients into intensity variations, yielding relief-like contrast without beam-shearing interferometry or objective-specific optical components.
Controlled comparisons demonstrate that neither retardation nor oblique illumination alone produces the characteristic DCMI effect; directional contrast emerges only from their combined interaction. Back focal plane observations confirm that contrast arises from deliberate pupil shaping rather than post-acquisition processing or chromatic artifacts. Specimen-plane Fourier analysis further demonstrates redistribution of image energy toward mid-spatial-frequency bands and increased directional anisotropy, consistent with enhanced phase-gradient sensitivity rather than resolution gain.
The method is highly tunable, with contrast behavior governed by wedge geometry, retardation order, pupil coverage, and illumination conditions. This flexibility enables adaptation across specimen types, including diatoms and crystalline materials, providing an accessible and extensible approach to qualitative phase visualization.
Controlled comparisons demonstrate that neither retardation nor oblique illumination alone produces the characteristic DCMI effect; directional contrast emerges only from their combined interaction. Back focal plane observations confirm that contrast arises from deliberate pupil shaping rather than post-acquisition processing or chromatic artifacts. Specimen-plane Fourier analysis further demonstrates redistribution of image energy toward mid-spatial-frequency bands and increased directional anisotropy, consistent with enhanced phase-gradient sensitivity rather than resolution gain.
The method is highly tunable, with contrast behavior governed by wedge geometry, retardation order, pupil coverage, and illumination conditions. This flexibility enables adaptation across specimen types, including diatoms and crystalline materials, providing an accessible and extensible approach to qualitative phase visualization.
Atomic Force Microscopy: An Overview
Andrew A. “Tony” Havics — pH2 LLC
Most microscopical techniques involve the use photons or electrons focused by a lens (optical or electromagnetic). Atomic Force Microscopy (AFM) uses force feedback from an ultra-small probe mounted on a cantilever as it is placed on or over a surface. Typically, the force feedback is based on transfer of energy to the tip and then bending in the cantilever holding the tip. It is this bending in the cantilever that is measured using a laser (optical) beam. So, the optical portion in an AFM is a deflection of the beam. The probe tip style and size can be constructed to highlight interactive features between the tip and a surface, for instance, elastic and friction forces of the material surface. The probe material construction may be altered to respond to magnetic as well as electrostatic forces, both on and above the material surface. This vertical (z) feedback in combination with x-y scanning generates a 3D image of the various forces at the surface, depending on the tip selection, x-y scanning process, and tip excitation with a piezoelectric actuator. The vertical (z) resolution is as low as a nanometer or two, however, the common vertical (z) range for AFM is only about 6 um, limiting is application to fairly flat areas of interest on surfaces.
TUESDAY AFTERNOON
TBA
Ethan Groves — Microtrace LLC
One Wandering Criminalist and Microscopist’s Short History with FT-IR and Micro-Spectrophotometers
Thomas A. Kubic — Science Department, John Jay College of Criminal Justice, CUNY
FT-IR spectroscopy and micro-spectrophotometry in the visible and infrared portions of the electromagnetic spectrum are commonly used in modern criminalistics laboratories and others. This paper describes the author’s experience with early FT-IR forensic analyses and his experiences with an analog micro-spectrophotometer (MSP). He will trace his work beginning in the mid-1980s with these techniques and report on the improved developments he has witnessed to the mid-2020s. There will be NO earth shattering Nobel revelations here, but his meanderings may be of interest to the historical-minded scientist and microscopist.
Applications of Laser Induced Breakdown Spectroscopy in a Pharmaceutical Microscopy Laboratory
Jan Burmeister, (presenting author), Martin Dähnrich - Berlin-Chemie AG, Berlin, Germany, and Diana Wochnik, bachelor’s student, Berliner Hochschule für Technik, Berlin, Germany
A combination of a powerful digital microscope and a laser-induced breakdown spectrometer (LIBS) was procured to enhance element-specific detection capabilities in a pharmaceutical microscopy laboratory.
This presentation will provide a detailed account of the measures implemented to establish the instrument within a regulated pharmaceutical laboratory setting. This process entailed the qualification of the instrument and the implementation of a daily Performance Qualification (PQ) test. In addition, a number of real-world application cases will be presented, exemplifying the instrument's utility in addressing quotidian inquiries that arise in our laboratory.
Utilizing Polarized Light Microscopy and Raman Microspectroscopy for in situ Sample Analysis
Jared Estévanes — Microtrace, LLC
When inspecting an unknown specimen, the early steps of analysis usually include mounting the sample for examination by polarized light microcopy (PLM). This step is crucial for understanding the nature of the sample, including determining potential identifications. While numerous components can be confidently identified by PLM, some identifications require further instrumental analysis.
Once a potential candidate for analysis has been identified by PLM, a challenge arises in how to best investigate the particle. Particles can be small, mixed in a sea of other particle species, and might potentially be mounted using non-volatile mounting media. Additional manipulation to isolate and analyze the particle of interest increases the risk of losing it, especially if it is small in size.
Utilizing PLM in situ on a Raman microscope can alleviate most of these concerns by allowing the analyst to relocate the particles of interest, confirm their properties, and ultimately obtain chemical information—all without particle isolation. While additional factors must be considered, this scheme reduces the risk of particle loss due to handling and allows the analyst to examine a specific target of interest. This talk will discuss the application of Raman spectroscopy to the in-situ analysis of already mounted particles, in light of the practical challenges that arise.
Building a Home Microscopy Laboratory
Dickey Huntamer
Microscopists often take their work home, often acquiring a personal microscope to enjoy the unseen world around them. The lab at home started as a simple desk to hold microscopes in the spare bedroom, but over time acquisition of additional equipment and laboratory supplies to support the observations with the microscope inevitably resulted in a dedicated microscopy laboratory space constructed in the basement. The basement area was unfinished so walls, floors, electrical, lighting, and plumbing needed to be added to make the space usable. Bench work was improvised from tables and commercial home cabinets along with some laboratory casework, such as storage spaces, shelving etc., that was found on the internet. A deionized water system and sink was added to provide suitable water for chemical analysis. Storage cabinets for chemicals, solvents, and reference samples were constructed. Bookshelves and file cabinets provide storage for reference books and manuals. Collections of sediments and soil samples together with laboratory supplies are stored in a small storage room in the basement next to the laboratory. The result was a practical and usable space for chemical and optical microscopy.
TBA
Sebastian Sparenga — McCrone Research Institute
WEDNESDAY, JUNE 17
WEDNESDAY MORNING
Polarized Light Microscopy and Microanalysis of Tableting Mixtures
Andrew Bowen — U.S. Postal Inspection Service
One of the trends observed by the seized-drug community over the past couple decades has been the rise in illicit and counterfeit pressed tablets. Tablet presses and dies can be purchased through on-line marketplaces, whole or in parts to be assembled separately. Ready-to-use tableting mixtures are also available from a variety of on-line vendors, including from manufacturers in foreign countries.
Numerous bags of tableting powders from an apparent illicit tableting operation were submitted to the U.S. Postal Inspection Service National Forensic Laboratory for analysis. The laboratory request included the identification of non-controlled substances in suspected tableting mixtures to provide evidence of the intent to produce illicit tablets. A wide variety of organic and inorganic inactive ingredients were identified in the tableting powder mixtures, including some surprising components.
Given the nature of the mixtures encountered, polarized light microscopy was particularly well-suited to determine the powder compositions. The results of the analysis of these tableting powder mixtures will be discussed in detail during the presentation, which will highlight the important role that polarized light microscopy played in the examination.
Numerous bags of tableting powders from an apparent illicit tableting operation were submitted to the U.S. Postal Inspection Service National Forensic Laboratory for analysis. The laboratory request included the identification of non-controlled substances in suspected tableting mixtures to provide evidence of the intent to produce illicit tablets. A wide variety of organic and inorganic inactive ingredients were identified in the tableting powder mixtures, including some surprising components.
Given the nature of the mixtures encountered, polarized light microscopy was particularly well-suited to determine the powder compositions. The results of the analysis of these tableting powder mixtures will be discussed in detail during the presentation, which will highlight the important role that polarized light microscopy played in the examination.
Ink and Pigment Analysis of the Voynich Manuscript
Joseph G. Barabe — Barabe & Associates LLC
The Voynich Manuscript is famous as a frustrating challenge to cryptographers worldwide. Despite numerous attempts, both the script and the language remain undeciphered. In 2009, the author was asked, through McCrone Associates, to analyze its material constituents, the inks used to create the text, and the pigments present in the numerous – and very strange – drawings. More than twenty samples were collected from the document, each of which was analyzed with multiple instruments, including SEM-EDS, FTIR, Raman microspectroscopy, XRD, and, of course, PLM. Some of the materials are well known; some remain somewhat mysterious. This presentation will introduce the essentials of this mysterious document, describe the analytical methods used, and why they were used, and the results they provided. This material was recently presented via Zoom at a half-day Voynich Manuscript conference sponsored by the Universität zu Köln and the Bergische Universität Wuppertal.
Microscopy of Early Inorganic Yellow Pigments at Colonial Williamsburg
Kirsten Travers Moffitt — Colonial Williamsburg Foundation
At the Colonial Williamsburg Foundation, optical microscopy forms the backbone of analytical research applied to a collection comprising more than 89 original eighteenth-century buildings and extensive holdings of eighteenth and early nineteenth-century decorative and folk arts. This presentation will explore three important yellow inorganic pigments: Patent yellow (Pb7O6Cl2); orpiment (As2S3); and chrome yellow (PbCrO4), that have been the subject of focused research by the author and whose identification relied fundamentally on cross-section and polarized light microscopy (PLM) techniques.
Patent yellow, a little-researched lead oxychloride pigment with a narrow period of use (1781–ca.1830), can be challenging to confirm with advanced techniques, but is easily identified using PLM, and was critical to understanding artifacts like a late 18th century Hessian tenor drum. PLM also enabled the unexpected identification of orpiment in an eighteenth-century architectural paint at the Catherine Orr house (ca. 1730) prompting further discovery of its use throughout several buildings in Williamsburg, despite its condemnation in period house-painting treatises. Finally, a revised history of chrome yellow in America will be discussed, integrating archival research with microscopy to establish a more precise introduction date (1809) and better contextualize artworks and significant historic buildings like the Bray School (est. 1760).
Occasional Unexpected Results in Analyzing Different Types of Paper Products
Walter J. Rantanen — SGS-IPS Testing
Many paper, paperboard, tissue, or other paper products may have labels or else be visually apparent as to their nature. Fiber analysis of these products, at times, can reveal that they are not what is claimed or a variation of what is expected. A number of different examples of paper products were analyzed for their fiber composition. Examination under the light microscope and using staining techniques can reveal these unexpected results. Occasionally, these anomalies can be found in many different types of paper products. These findings can reveal interesting processes within the paper industry.
Jean-Michel Basquiat’s Lost Subway Portfolio: Fact or Fiction
Nicholas Petraco — Petraco Consulting
This presentation reports the findings of a scientific forensic inquiry into the origins of a collection of small postcards, drawings, and paintings believed to be early works by the artist Jean-Michel Basquiat that he created while he was living on the streets of the Lower East Side of Manhattan between the mid-1970s until the very early 1980s. These works were obtained from the finder of an art portfolio who claims Jean-Michel Basquiat left them on an NYC subway car in 1980. In 1996, Julian Schnabel, a contemporary neo-expressionist artist and the director of the American biographical dram film entitled BASQUIAT, independently verified this event.
A recently published book (2022) written by members of the Basquiat estate entitled: “Jean-Michel Basquiat: King Pleasure,” contains a sundry of intimate unknown facts of Basquiat’s early private and personal family life, which were thoroughly studied and researched in detail for this investigation. The information acquired from this illuminating text was utilized to determine if the questioned works obtained from the lost subway portfolio are genuine early works by Basquiat, or forgeries. Thus, two hypotheses were formed, studied, and tested. The first hypothesis is that the finder of the portfolio is a forger of Basquiat’s artwork. The second is that the finder of the art portfolio is telling the truth.
The collected empirical data acquired in this investigation, employing a number of different forensic methodologies, showcases the strength of the forensic paradigm for use in art authentication. In this case, data from the chemical analysis of the unusual media and substrates used by the artist, together with forensic trace evidence, document and handwriting analysis, touch DNA examination, fingerprints, and footwear pattern evidence, provides a strong body of probative evidence for determining the author of the questioned works of art. The resulting scientific evidence obtained in this extensive forensic inquiry is unmistakable. Evidence which supports Basquiat created the works found in the portfolio, and stored images and sketches of his designs and ideas, are evident. Many of the same images appear in the apartment he lived in on 12th Street in the Lower East Side from mid-1979 to mid-1980, on the neighborhood’s concrete walls, in the images he created in his early life at home, published in “King Pleasure,” and in his notebooks. Therefore, the presenter rejects the first hypothesis that the finder of the lost subway portfolio is a forger of Basquiat’s early works, and that the works obtained from the questioned subway portfolio are genuine artworks by Jean-Michel Basquiat.
Uninvited Guests: Forensic Analysis of Foreign Bodies Recovered from Anatomical Orifices
Brianna Alarcon — Microtrace LLC
Following a hospital visit, caregivers sought answers after a large black mass was recovered from a patient’s throat after an otherwise typical day. In an unrelated case, healthcare providers became concerned upon discovering a large “stone” within the vaginal cavity of an adult patient.
To address these concerns, materials from both cases were submitted for forensic analysis. Despite their differing circumstances, both cases underscore the importance of a multidisciplinary approach to effectively identify and, in some cases, determine the origin of unknown samples. Techniques including polarized light microscopy (PLM), microchemical testing, chemical analyses, and elemental characterization were used to determine the composition and origin of the materials, which were ultimately identified as an accumulation of human head hair, in one case, and a biologically derived vaginal stone in the other.
The results of these analyses will be presented in the context of each case, emphasizing the importance of communication between scientists and investigators, when addressing complex and often unexpected forensic questions.
To address these concerns, materials from both cases were submitted for forensic analysis. Despite their differing circumstances, both cases underscore the importance of a multidisciplinary approach to effectively identify and, in some cases, determine the origin of unknown samples. Techniques including polarized light microscopy (PLM), microchemical testing, chemical analyses, and elemental characterization were used to determine the composition and origin of the materials, which were ultimately identified as an accumulation of human head hair, in one case, and a biologically derived vaginal stone in the other.
The results of these analyses will be presented in the context of each case, emphasizing the importance of communication between scientists and investigators, when addressing complex and often unexpected forensic questions.
Building Inexpensive Microscopes with 3D Printing
Kevin Brady — K A Brady & Associates LLC
The power of microscopes to advance science, solve mysteries, and improve health care is indisputable. Good quality scientific instruments are expensive and at times require specialized training to use effectively. An Internet search for open source models provides a few interesting examples. An intriguing website called OpenFlexure (1) provides an elaborate, low-cost, design of automated scanning microscopes with features that rival the capabilities of commercially available microscopes costing thousands of dollars. The presenter’s curiosity led them to build and test the capabilities of these microscopes. This presentation will discuss some of the results, experiments, and experience with these devices.
1. https://openflexure.org (accessed on May 11, 2026).
Useful Modifications and Extensions to the McCrone Glass Block
Jan Burmeister (presenting author) and Martin Dähnrich — Berlin-Chemie AG
The versatility of the McCrone glass block as a vital tool for sample handling and preparation has been recognized by microscopists associated with the McCrone Research Institute since its inception. This presentation will outline some useful modifications, alterations, and expansions that are part of everyday "microlab life" at Berlin-Chemie AG. These alterations encompass modifications in size, color, and internal structure, among other characteristics. Two additional extensions will be presented, which can be used to test for ferromagnetism and electric conductivity of small particles.
WEDNESDAY AFTERNOON
TBA
Otyllia Vercellato — Microtrace LLC
Photomicrography: Adding Color Optically to Your Image
Andrew A. “Tony” Havics — pH2 LLC
Photomicrography is not just something you do to explain what you found under the microscope, it is also an art form. We see this by the number of photomicrography competitions held each year. Although preparing a colorful or vibrant image can be a matter of material selection, particularly with polarized light microscopy, there are techniques that can be used to create a new color where there is not, or add color onto to an existing color, or shift the color, or distribute the color differently. These can all be done optically in-situ, perhaps with a little sample re-arrangement, as opposed to post-processing digitally using software.
So You Have an Interference Filter (and/or a Monochromator) and Therefore Know the λmax of Transmission: Think Again
Thomas A. Kubic — Thomas A. Kubic & Associates, John Jay College of Criminal Justice, CUNY
When performing measurements of physical or chemical nature, it is important to ensure that the instrument being employed has been properly calibrated. This is the case whether one is employing a mass spectrometer, visible spectrophotometer, microscope, linear caliper or other device. This is even more critical if the measurement is being performed for possible litigation issues.
Quality standards are required to perform these calibrations and many accreditation organizations require that the traceability specifying accuracy and uncertainty be documented, i.e., traceable standards linked back by an unbroken chain to a Standard Reference Material (SRM), International System of Units (SI) or other high quality material through a documented continuous comparison process with documented uncertainties for each step in the calibration process. Standards from internationally recognized sources such as NIST’S SRM and Reference Materials (RM) with well-characterized properties but do not meet the strict certification criteria of a SRM, and those based on internationally accepted SI values such as the emission wavelengths of gases or, in some cases, consensus standards are always preferred. Consensus standards are those accepted by all interested parties as fit for a specific purpose although not certified. For example, the mineral albite is accepted by the National Voluntary Laboratory Accreditation Program (NVLAP) for k-factor determination of the metallic element aluminum.
Forensic microscopists measuring refractive indices, especially those comparing glass samples, employing any of the manual techniques such as Becke line, single variation, double variation, or even automated instrumental methods like the Glass Refractive Index Measurement System (GRIM) often rely on interference filters or monochromators to supply specific (or nearly specific; there is a band pass range) monochromatic light in their endeavors (1—4).
The assumption that these wavelength standards are what they are purported to be, may not be valid. In this presentation, the author will report on the investigation of these light sources employing a fiber optic spectrometer, the calibration of which was verified to SI references. Also studied, and in preparation for publication in an upcoming issue of The Microscope journal, were a number of interference filters, a rotating and tilting interference filter monochromator, and two dispersive monochromators.
Quality standards are required to perform these calibrations and many accreditation organizations require that the traceability specifying accuracy and uncertainty be documented, i.e., traceable standards linked back by an unbroken chain to a Standard Reference Material (SRM), International System of Units (SI) or other high quality material through a documented continuous comparison process with documented uncertainties for each step in the calibration process. Standards from internationally recognized sources such as NIST’S SRM and Reference Materials (RM) with well-characterized properties but do not meet the strict certification criteria of a SRM, and those based on internationally accepted SI values such as the emission wavelengths of gases or, in some cases, consensus standards are always preferred. Consensus standards are those accepted by all interested parties as fit for a specific purpose although not certified. For example, the mineral albite is accepted by the National Voluntary Laboratory Accreditation Program (NVLAP) for k-factor determination of the metallic element aluminum.
Forensic microscopists measuring refractive indices, especially those comparing glass samples, employing any of the manual techniques such as Becke line, single variation, double variation, or even automated instrumental methods like the Glass Refractive Index Measurement System (GRIM) often rely on interference filters or monochromators to supply specific (or nearly specific; there is a band pass range) monochromatic light in their endeavors (1—4).
The assumption that these wavelength standards are what they are purported to be, may not be valid. In this presentation, the author will report on the investigation of these light sources employing a fiber optic spectrometer, the calibration of which was verified to SI references. Also studied, and in preparation for publication in an upcoming issue of The Microscope journal, were a number of interference filters, a rotating and tilting interference filter monochromator, and two dispersive monochromators.
1. Bloss, F. D. Optical Crystallography, Mineralogical Society of America, Monograph No. 5, p. 239, 1999. 2. Ojena, S.M.,and DeForest, P.R. "Precise Refractive Index Determination by the Immersion Method Using Phase Contrast Microscopy and the Mettler Hot Stage," Journal of Forensic Science Society, 12:3, pp. 315—329, 1972.3. Emmons, R. C. “ The Double Variation Method of Refractive Index Determination” American Mineralogist, 14:11, pp. 414—426, 1929. 4. Locke, J. and Underhill, M. “Automatic Refractive Index Measurement of Glass Particles,” Forensic Science International, 27:4, pp. 247—260, 1985.
TBA
Skip Palenik — Microtrace LLC
Around the World in Sands
Kate Clover (presenting author) and Leo Kenney
In this presentation, we'll take a spin around the world with Leo Kenney's macrophotographs of sands. We'll preview and learn about the variety of sand grains found across the Great Lakes, on tropical islands, and along oceans and inland rivers. Each sand tells a story of the regional geology, the marine ecosystem, or industrial history. Prepare to be amazed!
TBA
Meggan Dempsey — McCrone Research Institute