Advances in Fingerprint Technology.pdf

Large vacuum chambers for processing a variety of objects are available
commercially. Margot and Lennard 9 generally agree on the usefulness of this
procedure.
Other Acceleration Procedures
Many other acceleration procedures have been used, including heating combined
with circulation, intense heating combined with the addition of polymerization
retardant to the cyanoacrylate, moist vapor combined with
heating, cyanoacrylate in gel media, and combinations of chemical accelerators.
All these techniques have the same two basic objectives: (1) accelerate
the polymerization process and (2) prolong the volatilization. Grady 57
described good results from a combination of heating within a vacuum
chamber. He noted that although development could not be monitored,
overfuming was rare and that background dye stain fluorescence was reduced.
Cyanoacrylate ester has been incorporated into a gel matrix that is placed
in a foil pouch that is reusable and has wide applications for processing latent
prints. In 1985, Gilman, Sahs, and Gorajczyk 58 also reported a similar method
in which a mixture of cyanoacrylate and petroleum jelly are sandwiched
between acetate sheets. It has also been found that cyanoacrylate fuming is
an excellent method for processing latent prints in motor vehicles and in
small enclosed spaces at crime scenes. Olenik 59 has described another sandwich
technique in which a thin film of cyanoacrylate is placed between
aluminum foils by the use of a fingerprint roller.
Even when care is exercised, fingerprints can be overdeveloped with
cyanoacrylate. Springer 60 noted that carefully controlled heating of the overdeveloped
print at 70 to 80°C can selectively remove enough cyanoacrylate
polymer to render the print identifiable. However, one cannot re-fume the
latent after this procedure has been used. The technique was based on the
observation by Almog and Gabay, 61 later confirmed by Davis, McCloud, and
Bonebrake, 62 that polymerized (solidified) Super Glue produces fumes, i.e.,
monomeric vapor, upon heating. Geng described several methods of applying
organic solvent mixtures (such as spraying, dipping, etc.) to overdeveloped
Super Glue prints to render them more suitable. 63 The composition of
the treating solvent and method of application depended on the surface.
Though not an “acceleration” procedure, Zhang and Gong 64 described a
cyanoacrylate ester dry transfer method that placed test objects in contact
with neutral filter paper that had been pre-treated with Super Glue, then
dried. Additionally, various applications to special situations or conditions,
such as large or immovable objects, plastic bags, leaves, surfaces contaminated
by cigarette smoke residues, etc., have been noted periodically. 65-70