General Study Guide - Ontario Police College

Fluorescent Powders – Some substrates have a confusing , multi-coloured background
pattern from which it is difficult or impossible to photographically separate the
impression. Use of fluorescent powder will allow photography of the impression using
UV techniques with little or no background interference.
It is recommended that the piece of evidence be treated with glue fumes initially before
application of fluorescent powders. It is better to "underfume" than to "overfume" as
the fluorescent powders adhere to the glue residue. If the entire surface is heavy with
white residue, the powder may adhere to the entire surface and it will glow so strongly
that the fine details in the latent prints may be lost. Glue-fuming in a vacuum system
causes the glue to adhere to latent print ridge details and prevents the glue residue
from adhering to the entire surface.
Fluorescent powders are very fine powders with a Lycopodium base. It has been
reported that they seem to be best for wooden surfaces, such as rifle stocks and wood
paneling. Whenever liquid dye staining might damage the object being examined or in
field work situations where liquid dye staining is a problem, fluorescent powders can be
used instead.
Fluorescent - The
goal is to choose
the colour of
powder that will
fluoresce at a
different
wavelength than
the background.
Fluorescent powders have the
same powdering characteristics
as white powder.
It is recommended that a feather
duster be used to apply
fluorescent powders under a UV
light source for best results.
** Caution – Proper UV eye &
skin protection must be worn at
all times.
Fluorescent powders work well
under argon-ion, copper-vapor
and Nd:YAG lasers, along with
Forensic Light Sources and longwavelength
ultraviolet lights.