modernmicroscopy : articles

Holographic Glitter
by  Kurt Gaenzle, Senior Materials Engineer, San Diego, CA
Edwin L. Jones Jr., Forensic Scientist III, Ventura, CA
Bob Blackledge, Forensic Chemist Consultant, El Cajon, CA

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METHODS

All glitter particles examined in this study were purchased from Meadowbrook Inventions, Inc., 260 Minebrook Road, Bernardsville, NJ 07924-0960, USA (www.meadowbrookinventions.com). All were either from their product line Alpha Jewels HTMP or Alpha Jewels. They describe Alpha Jewels HTMP as "Precision cut Holographic Glitter particles consisting of Micro-embossed Aluminum particles designed for applications requiring Prismatic Special Effect with excellent Heat Resistance." Alpha Jewels are described as "Precision cut Holographic Glitter particles consisting of micro-embossed vacuumed metalized (0.5% aluminum) polyethylene terephthalate, designed for applications requiring Prismatic Special Effect with excellent fastness properties. Solvent Resistant." Alpha Jewels HTMP are further described as having a thickness of 0.001" (25 micrometers) and a specific gravity of 2.4, with the Alpha Jewels having a thickness of 0.002" (50 micrometers) and a specific gravity of 1.4. Alpha Jewels are offered in the following six colors: Silver, Gold, Strato Blue, Pink, Ocean Green, and Lavender. They are offered as square particles  0.008" along a side; rectangular particles 0.035" x 0.004", 0.062" x .0125", or 0.125" x 0.0125", as hexagonal particles 0.008" (one apex to opposite apex), 0.015", 0.025", 0.040", 0.062", and 0.094". Also, specialized shapes are available as 1/8" stars, hearts, or diamonds.

 

In this study the following 12 glitter products were examined:

 

Sample #001 Alpha Jewels HTMP Silver 0.008" x 0.008" (Figures 2a-2d)

Sample #002 Alpha Jewels HTMP Silver 0.025" hexagonal

Sample #003 Alpha Jewels Silver 0.008" x 0.008"

Sample #004 Alpha Jewels Silver 0.025" hexagonal

Sample #005 Alpha Jewels Gold 0.008" x 0.008"

Sample #006 Alpha Jewels Gold 0.025" hexagonal

Sample #007 Alpha Jewels Strato Blue 0.008" x 0.008"

Sample #008 Alpha Jewels Strato Blue 0.025" hexagonal

Sample #009 Alpha Jewels Pink 0.008" x 0.008"

Sample #010 Alpha Jewels Pink 0.025" hexagonal

Sample #011 Alpha Jewels Ocean Green 0.008" x .008"

Sample #012 Alpha Jewels Ocean Green 0.025" hexagonal

 

[Sample numbers are not Meadowbrook Inventions numbers but were used by the authors in previous studies. Correspondingly numbered small samples were issued to the attendees at a workshop on glitter presented on 13 August 2007 in Clearwater Beach, Florida as part of a Trace Evidence Symposium sponsored by the National Institute of Justice and the Federal Bureau of Investigation.]

 

Glitter photos settings: The samples were prepared by dry mounting a small sample of glitter on a standard glass slide with no coverglass.  The images were viewed with a Nikon MM-40 measuring microscope equipped with LU Plan objectives [5x (0.15 NA), 50x (0.55 NA), and 100x (0.80 NA)].  Illumination used standard tungsten bulb, reflected brightfield condition, no neutral density or polarizing filters were inserted in the light path.  Photographs were taken with a SPOT-RT color CCD camera (model 2.2.1.) and SPOT version 4.7 software set on auto gain and auto exposure.  Micrometer markers in the photographs were calibrated against a MicroRuler MR-1 (s/n 5-14) size reference standard.


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