Vacu-Box
Instruction Manual
Vacu-Box Safety Information
- Keep the unit dry and clean
- Read all of the instructions
before using
- Electric shock can occur if used
improperly
Description of Equipment
- Electrostatic Vacuum Box
- Dimensions: 39 x 35 x 17.0
cm (approximately 15 1/8" x 13 3/4" x 6 3/4")
- Weight: 10 kg (22 lbs.)
- Roll of Type IW film, 40 cm x
100 meters (approximately 15 3/4" x 328')
- Adhesive film, 24 sheets, 25
x 35 cm (approximately 9 3/4" x 13 3/4")
- Corona Unit
- Developing Powder, 75 grams
- Developing Brush
Background
In criminal cases where documents are present, e. g.,
drug transactions, kidnap notes, bank hold-up notes, forged
checks, etc., handwriting may be present which is not
visible under normal conditions. There may have been writing
which was done on a piece of paper which left indentations
in the document in custody. The procedure in the past
was to use oblique lighting to photograph any indented
writing which may appear. This process was not always
successful.
A solution to this problem is to
use electrostatic energy and black powder. The document
is placed on a vacuum plate, covered with a sheet of plastic
film, and charged with electricity. A special black powder
is brushed over the surface. The high-voltage electric
charge will cause the black powder to collect in the indentations,
making the writing easy to see and easy to photograph.
Because the original document is covered with plastic,
it is not damaged or altered. The image of indented writing
can be saved by placing an adhesive cover sheet on the
plastic film.
Directions for Operation - Indented
Writing
Helpful Hints
-
If the paper evidence is also
going to be examined for latent prints, perform the
indented writing development first. Processes like
Ninhydrin or Physical Developer are wet processes
which will destroy indented writing.
-
When applying the developer
powder to the film in indented writing recovery, apply
it in long stokes, first side to side, then top to
bottom. Apply small amounts of powder. More can be
added. Too much cannot be taken away easily.
-
Only the center of the Corona
unit is active. Use the center of the Corona unit
to charge the film and paper. When passing the Corona
unit over the film, it is easy to miss the edges and
corners of paper, so be certain that the active area
of the Corona unit passes over the entire surface
of the paper. Do not set the Corona unit down on top
of the film and paper while processing, as it will
produce a dark area of powder if using it for indented
writing.
-
If too much powder is used and
it seems that some writing is "overdeveloped," just
start over with a new piece of IW film. The document
is never damaged or altered.
Photography Tips
-
For photography of indented
writing, a medium-contrast to high-contrast film should
be used. Do not use color films, as they do not show
contrast as well as black-and-white films.
-
While small-format film in 35mm
cameras can be used, medium- to large-format cameras
are recommended. The Polaroid MP-4 or MP-4 Plus or
other style of copy stand large-format film cameras
use 4 x 5 sheet film and have methods for controlling
the amount and direction of the light.
Care and Maintenance
Replacement Supplies
Catalog No. 4-5527 Type IW film,
100 m roll
Catalog No. 4-5528 Developing Powder, 75 g
Catalog No. 4-5529 Adhesive Sheets, 25 sheets
Catalog No. 1-0035 Developing Brush
© 1995 Lightning Powder Company,
Inc., Salem, Oregon, USA
Prepared by Kathleen D. Saviers, CLPE, CSCSAB
Introduction
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The goal of latent print examiners
and technicians is to discover and collect latent
prints by various means. The ultimate goal is to
identify those latent prints to the person responsible
for the criminal act and prosecute them to the fullest
extent of the law. Some of these means to develop
latent prints include processing evidence and other
surfaces using powders, chemicals and lighting techniques.
The purpose of this booklet is to provide a resource
of information about latent print processing techniques.
This booklet does not contain every process available
and does not claim to be all inclusive of all variations
of processes. The information has been collected
from various sources.
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Caution
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This booklet contains descriptions
of processes utilizing chemicals or combinations
of chemicals which may be hazardous to the user's
health. It is strongly recommended that proper precautions
be taken when using hazardous chemicals or combinations
thereof. Safety equipment needed may include fume
hoods, gloves, protective clothing, safety goggles,
splash shields or respirators. It may be necessary
to store these chemicals in specific containers
or cabinets. It is the user's responsibility to
know and use the proper and adequate safety equipment
required the various chemicals listed.
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Disclaimer
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Lightning Powder Company,
Inc. assumes no responsibility for the use or misuse
of any of the chemicals, procedures, methods of
ideas described herein resulting in injury and/or
damage to persons or property.
Copyright © 1998 Lightning Powder
Company, Inc.
The material contained in and displayed by this
website may be reproduced with acknowledgment of
its source.
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