Powders
Powders adhere to both water and fatty deposits. These are generally useful
on newer prints only. Choose a powder to contrast with the background. They
are useful on any dry, relatively smooth, non-adhesive surfaces. Use after
laser fluorescence. May be used before ninhydrin and after cyanoacrylate.
Results may vary with skill of technician. “Lift” developed prints by
photography or conventional methods.
Fluorescent Powders
Powders made of fluorescent materials offer advantages to the limitations of
conventional powders. Apply as with conventional powders. “Lifts” can be
made photographically or by conventional means. Fluorescent powders are
especially useful on confused backgrounds. An ultraviolet or forensic light
source is required.
Iodine Fuming
Iodine fumes react with oils and fatty deposits to produce a temporary
yellow-brown reaction product. Iodine is useful on fresh prints on porous
and non-porous, non-metallic surfaces. Developed prints must be fixed or
photographed immediately because reaction will rapidly fade. Use iodine
before ninhydrin and silver nitrate.
DFO
DFO, 1,8 Diazafluoren-9-one, is a fluorescing ninhydrin analog found to
develop up to two and a half more prints than ninhydrin itself. It is useful on
porous surfaces, especially paper. Development may be accelerated through
the application of controlled heat. Use it before ninhydrin. DFO also is useful
to develop weak blood stains. It requires a specialized light source, such as
the BLUEMAXX™.
Ninhydrin
Ninhydrin reacts with amino acids to produce a purple reaction product
called “Rhuemann’s Purple”. It is useful on porous surfaces—especially paper.
Development time is up to 10 days, but may be accelerated through the
application of heat and humidity. Use ninhydrin after iodine and before silver
nitrate. Ninhydrin is not useful on items which have been exposed to water.
Silver Nitrate
Silver nitrate reacts with the chlorides in skin secretions to form silver
chloride, a material which turns gray when exposed to light. Developed prints
must be photographed immediately because the reaction will eventually (and
permanently) fill the background. It is useful on paper, cardboard, plastics and
unvarnished, light-colored woods. Use it after ninhydrin and iodine. It is not
useful on items which have been exposed to water.
Physical Developer
Physical developer is another silver-based developer which reacts to form a
dark gray reaction product. It is useful on paper, cardboard, and unvarnished,
light-colored woods. Use physical developer after ninhydrin and iodine. It is
very successful on items exposed to water.
Cyanoacrylate (Glue Fuming)
Cyanoacrylate fumes react (polymerize) with water and other possible
fingerprint constituents to form a hard, whitish deposit. It is useful on most
non-porous and some porous surfaces. Cyanoacrylate produces excellent
results on styrofoam and plastic bags. Developed prints may be dusted with
powders or treated with fluorescing dyes, such as ardrox and basic yellow to
enhance.
Amido Black
Amido black reacts with the proteins found in blood to form a black reaction
product. Amido black is useful only on blood-contaminated prints. It is highly
sensitive. It is useful on non-porous and some slightly porous surfaces. It
sometimes offers successful development of blood prints on dead human
skin
Adhesive Side Powder
Adhesive side powder attaches itself to plastic print impressions on the
adhesive side of tapes. It produces excellent results on light-colored or
transparent tapes, including duct tape, masking tape, plastic surgical tape,
foam tape, clear and reinforced packing tapes and labels. This process
involves wetting tapes.
Fluorochromes
Prints may be treated with special dyes called fluorochromes which easily
are made to fluoresce and bond with the print deposits. They are useful
with forensic lights such as SIRCHIE’s BLUEMAXX™. DFO is a fluorescing
ninhydrin analog found to develop up to two and a half times more prints
than ninhydrin itself. It is useful on porous surfaces. Development may be
accelerated through the application of controlled heat. A specialized light
source such as SIRCHIE’s BLUEMAXX™ is required. Basic yellow, ardrox, and
rhodamine are dyes especially useful staining latent prints developed with cyanoacrylate.
Download more information: Latent print Development
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