||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
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.