•
`
`MANUAL OF
`
`FINGERPRINT DEVELOPMENT
`
`TECHNIQUES
`
`
`
`A GUIDE TO THE SELECTION AND USE OF PROCESSES FOR
`
`•
`
`
`
`THE DEVELOPMENT OF LATENT FINGERPRINTS
`
`SECOND EDITION
`
`1998
`
`
`
`(REVISED JANUARY 2001)
`
`•
`
`HOME OFFICE
`
`
`
`POLICE SCIENTIFIC DEVELOPMENT BRANCH
`
`SANDRIDGE
`
`•
`
`Reactive Surfaces Ltd. LLP
`Ex. 1042 (Ray Attachment H)
`Reactive Surfaces Ltd. LLP v. Toyota Motor Corp.
`IPR2016-01914
`
`

`

`© CROWN COPYRIGHT 1998
`
`SECOND EDITION 1998
`
`FIRST PUBLISHED 1986
`
`NEW IMPRESSIONS WITH CORRECTIONS 1987
`
`UPDATED 1987 and 1992
`
`.
`
`FOLLOWING UPDATES ISSUED TO REGISTERED HOLDERS
`
`DFO & NINHYDRIN 2001
`
`ISBN 1 85893 972 O
`
`The illustration on the front cover is an interference micrograph at approximately
`300 times magnification of a latent fingerprint on a glass slide. It shows ridges which
`consist of a series of droplets of various sizes together with cruciform shaped salt
`crystals. There is usually a background thin film of fats but this may only be a few
`molecules thick and is not normally visible optical/y. The deposit and glass substrate
`are colourless; the colours being generated by the ‘lnterphako’ interferometric
`technique within the microscope.
`
`Printed in England for the Home Office by White Crescent Press Ltd. Luton
`
`ii
`
`PSDB January 2001
`
`
`
`
`
`

`

`Chapter 1
`
`LATENT FINGERPRINTS
`
`
`
`

`

`2
`
`LATENT FlNGERPRlNTS
`
`LATENT FINGERPRINTS
`
`1.1
`
`INTRODUCTION TO THIS MANUAL
`
`Chapter 1
`
`.
`
`
`PSDB March 1998
`
`This manual provides information on the selection and use of processes for the
`development of latent fingerprints. The information has, where possible, been
`presented in a step by step manner.
`If followed carefully the instructions will
`result in successful implementation of the processes.
`
`is used to describe a latent
`the term 'fingerprint'
`this manual
`Throughout
`fingerprint found at a scene of crime or such a fingerprint after treatment with a
`development process, these are often referred to elsewhere as 'latents‘,
`'latent
`prints“,
`'prints' or ‘marks‘.
`
`Fingerprints contain many chemicals and vary widely in composition both from
`one individual to another and with one individual from day to day and minute to
`minute. Since generally the investigator knows nothing about the condition of
`the suspect's hands at the time of the crime it is impossible to predict the most
`effective process in specific cases. The investigator should therefore use the
`
`process with
`
`documented comparisons.
`
`the best overall performance determined from previous, .
`
`Whilst many comparative trials have been carried out on fingerprints deposited
`in laboratory conditions, the recommendations here are based principally on
`subsequent experience using substantial quantities of operational material.
`If
`in this manual a process is not recommended for a particular surface this does
`not imply that the process will not detect any fingerprints. The implication is that
`the reagents or processes recommended will give, on average, better results.
`
`ln important cases the use of two or more processes sequentially should be
`considered. This may dramatically improve the chance of success. When
`possible processes should be used in the best sequence as shown by the
`charts in Chapter 3.
`
`LABORATORY FACILITIES (Chapter 2, Section 2.1) and HEALTH AND SAFETY
`(Chapter 2, Section 2.3) must be read by all
`those involved in the use of
`fingerprint development processes.
`
`INTERFERENCE BETWEEN FINGERPRINT AND FORENSIC EXAMINATIONS
`
`(Chapter 2, Section 2.4) should be read by all those involved in selection and
`examination of articles.
`
`(Chapter 3,
`SEQUENTIAL PROCESSING AND THE USE OF THE CHARTS
`Section 3.1) should be read before deciding on the most appropriate process
`for a particular article.
`
`PROCESS INSTRUCTIONS (Chapter 4) provides comprehensive guidance on
`the most effective use of every recommended technique
`for detecting
`fingerprints.
`
`
`
`

`

`
`
`
`
`LATENT FINGERPRINTS 3
`Chapter 1
`
`1.2
`
`1.2.1
`
`LATENT FINGERPRINTS
`
`Introduction
`
`Latent fingerprints usually consist of a mixture of natural secretions from
`various glands in the skin but may often be contaminated with other materials
`present
`in the environment and picked up on the skin of
`the individual
`concerned. Some fingerprints may actually consist solely or principally of a
`contaminant.
`
`it is normally impossible from simple visual examination to determine the major
`constituents of a fingerprint, except when it is obviously made in a contaminant
`such as blood, grease, ink or dust.
`
`in
`Fingerprints may also be left as impressions in soft surfaces such as putty,
`which case the shape of the surface rather than the deposit itself may provide
`the fingerprint image which is required.
`
`Several researchers have determined the distribution of the major constituents
`of
`the secretions of
`the sweat glands. Others have examined the actual
`distribution in latent fingerprints. Wide variations from one donor to another
`have been found and with the same donor large variations occur from day to
`day and even minute to minute.
`
`1.2.2
`
`Secretions of sweat glands
`The main constituents of the secretions of the 3 types of sweat gland found on
`the human body are listed below. in addition there is a considerable amount of
`water secreted by the eccrine glands.
`
`SOURCE
`
`INORGANIC CONSTITUENTS
`
`ORGANIC CONSTITUENTS
`
`Eccrine glands
`
`Chlorides
`Metal ions
`Ammonia
`Sulphate
`Phosphate
`
`Sebaceous glands
`
`Apocrine glands
`
`iron
`
`Amino acids
`Urea
`Lactic acids
`Sugars
`Creatinine
`Choline
`Uric acid
`
`Fatty acids
`Glycerides
`Hydrocarbons
`Alcohols
`
`Proteins
`Carbohydrates
`Cholesterol
`
`Most natural fingerprints consist of a mixture of sebaceous and eccrine sweat.
`Some of these chemicals persist for long periods of time in latent fingerprints
`whilst others may decompose, evaporate or diffuse.
`
`in a fingerprint depends on the
`The presence of a specific chemical
`the nature of
`the surface,
`the time
`constituents of the original
`fingerprint,
`elapsed since deposition and the storage conditions. Factors such as
`temperature, exposure to light and water and the relative humidity change the
`chemical and physical nature of a fingerprint.
`
`PSDB March 1998
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`
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`

`

`4
`
`LATENT FINGERPRINTS
`
`Chapter 1
`
`Water is the first component to be lost from most fingerprints. For fingerprints .
`more than a few days old processes which primarily detect water are therefore
`generally less effective than those detecting the fatty components.
`
`1.2.3
`
`Detection of constituents of latent fingerprints
`Some fingerprint detection techniques are specific to particular chemicals
`whilst others detect the oily or greasy physical nature of the surface. A list of the
`various processes and the glandular secretions which they principally detect is
`given below.
`
`SEBACEOUS (FATTY) MATERIAL
`
`ECCRlNE (AQUEOUS) MATERIAL
`
`Visual Examination
`Powders
`
`Visual Examination
`Powders
`
`.
`
`.
`
`Physical Developer
`Vacuum Metal Deposition
`Small Particle Reagent
`Gentian Violet
`
`Sudan Black
`
`Iodine
`Radioactive Sulphur Dioxide
`
`Ninhydrin
`DFO
`Vacuum Metal Deposition
`Fluorescence Examination
`
`Radioactive Sulphur Dioxide
`
`Superglue
`
`Since the chemical and physical nature of a fingerprint is generally not known
`before the fingerprint examination it
`is impossible in an individual case to
`predict whether a particular technique will be successful. The routes on the
`process selection charts in this manual lead to the techniques which are most
`likely to be successful for a particular type of surface.
`
`1.2.4
`
`Determination of the age of a fingerprint
`Many fingerprint development techniques will sometimes show a change in the
`intensity or nature of reaction with older fingerprints compared with fresh
`fingerprints.
`it
`is however
`impossible to determine reliably the age of a
`fingerprint by observation of its reaction with a fingerprint detection process.
`
`1.2.5
`
`Bibliography
`
`Alexiou D, Anagnostopoulos A, Papadatos C.
`
`Total Free Amino Acids, Ammonia and Protein in the Sweat of Children.
`
`Am J Clin Nutr, 1979, April, p750, pp3.
`
`Aubert.
`
`Assoc. Francaise Pour L‘Advancement des Sciences.
`
`Congress Du Harve, 1877
`
`Bayford F.
`
`The Ageing of Fingerprints.
`
`Fingerprint Whor/d, 1977, July, p13, pp3.
`
`PS DB March 1998
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`

`

`
`Chapter 1
`LATENT FINGERPRINTS
`5
`
`Cowger J E.
`Friction Ridge Skin.
`
`Book, Published by Elsevier, 1983, p107, pp3.
`ISBN 0-444-00770-9
`
`Cuthbertson F.
`
`The Chemistry of Fingerprints.
`
`AWRE Report, 1965, 8/65.
`
`Cuthbertson F, Cripps F M.
`
`The Chemistry of Fingerprints.
`
`AWRE Report, 1965, SAC/2/65.
`
`Cuthbenson F, Morris J R.
`
`The Chemistry of Fingerprints.
`
`AWRE Report, 1972, SSCD Memo 332.
`
`Downing D T, Strauss J S, Pochi P E.
`
`Variability in the Chemical Composition of Human Skin Surface Lipids.
`
`J Invest Dermatol, 1969, V53, p322, pp6.
`
`Downing D T, Strauss J S.
`
`Synthesis and Composition of Surface Lipids of Human Skin.
`
`J Invest Dermatol, 1974, V62, N03, p228, pp17.
`
`Faulds H.
`
`Nature, 22, 605, 1880.
`
`Forgeot R.
`
`Laboratoire D' Anthropologie Criminal/e.
`
`Lyon, 1891.
`
`Frecon.
`
`Des Empreintes en General.
`
`These, Lyon, 1889.
`
`Galton F.
`
`Finger Prints.
`Book, Published by Macmillan and Co., 1892.
`
`Gitiitz H, Sunderman F W, Hohnadel D C.
`
`ion Exchange Chromatography of Amino Acids in Sweat Collected from Healthy Subjects
`during Sauna Bathing.
`
`Clin Chem, 1974, V20, N010, p1305, pp7.
`
`Goode G C ; Morris J R.
`
`Latent Fingerprints: A Review of Their Origin, Composition and Methods for Detection.
`
`AWRE Report No 0 22/83.
`
`PSDB March 1998
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`1
`E
`
`g
`:
`
`‘
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`
`
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`

`

`6
`
`LATENT FINGERPRINTS
`
`Chapter 1
`
`Haahti E.
`
`Major Lipid Constituents
`Chromatographic Methods.
`
`of Human Skin Surface with Special Reference
`
`to Gas
`
`Scand JCI/n Lab Invest, 1961, V13, Suppl 59, p1, pp109.
`
`Hamilton P B.
`
`Amino Acids on Hands.
`
`Nature, 1965, V205, p284, pp2.
`
`Henry E R.
`
`Classification and Uses of Finger Prints.
`
`Book, Published by George Routledge and Sons Ltd, 1900.
`
`Herrmann W P, Habbig J.
`
`immunological Demonstration of Multiple Esterases in Human Eccrine Sweat.
`
`BritJ Dermato/, 1976, V95, p67, pp4.
`
`Herrmann W P, Habbig J.
`
`immunological Studies on the Proteins of Human Eccrine Sweat.
`
`Arch Derm Res, 1976, V225, p123, pp6.
`
`Hier S W, Cornbleet T, Bergeim O.
`The Amino Acids of Human Sweat.
`
`JBio/ Chem, 1946, V166, p327, pp7.
`
`Itoh S, Nakayama T.
`Amino Acids in Human Sweat.
`
`Jap J Physiol, 1952, V2, p248.
`
`Johnson P L.
`
`Life of Latents.
`
`ldent News, 1973, April, p10. pp4.
`
`Jones R J.
`
`Chemistry of fingerprints: A Bibliography.
`
`HOCFiE Report 501, Sept 1983.
`
`Kuno Y.
`
`Human Perspiration.
`
`Book, Published by Charles C Thomas, Springfield, lllinois.
`lSBN 0-398-01066-8
`
`Knowles A M.
`
`Aspects of Physicochemicai Methods for the Detection of Latent Fingerprints; Review.
`J Phys E, 1978, V11, p713, P99.
`
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`

`

`
`
`7 Chapter 1 LATENT FINGERPRINTS
`
`
`
`Liappis N, Hungerford H.
`
`Quantitative Study of Free Amino Acids in Human Eccrine Sweat during Normal Conditions
`and Exercise.
`
`J Clin Nutr, 1972 V25, p661.
`
`Liappis N, Hungen‘ord H.
`The Trace Amino Acids in Human Eccrine Sweat.
`
`Clin Chim Acta, 1973, V48, p233, pp4.
`
`Locard E.
`
`Identification des Recidivistes.
`
`Paris, 1909.
`
`Marples M J.
`Life on the Human Skin.
`
`Sci Am, 1969, V220, No 1, p108, pp8.
`
`Morello A M, Downing D T.
`
`Trans-Unsaturated Fatty Acids in Human Skin Surface Lipids.
`
`J Invest Dermatol, 1976, V67, N02, p270, pp3.
`
`Nicolaides N.
`
`Skin Lipids, their Biological Uniqueness.
`
`Science, 1974, Oct, V186, p19, pp6.
`
`Nikkari T.
`
`Comparative Chemistry of Sebum.
`
`J Invest Dermatol, 1974, V62, N03, p257, pp11.
`
`Olsen Sr, R D.
`
`The Chemistry of Palmar Sweat.
`
`Ident, 1972, V4, p93, pp9.
`
`Prottey C.
`
`Essential Fatty Acids and the Skin.
`
`Cosmet Toiletr, 1977, V92, p59, pp3.
`
`Rothman S, Sullivan M B.
`Amino Acids on the Normal Skin Surface.
`
`J Invest Dermatol, 1949, V13, p319.
`
`Sargent F, Robinson P, Johnson Ft E.
`Water Soluble Vitamins in Sweat.
`
`JZoo Chem, 1944, V58, p285, pp11.
`
`PSDB March 1998
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`

`

`8
`
`LATENT FINGERPRINTS
`
`Chapter 1
`
`Thomas G L, Reynoldson T E.
`
`Some Observations on Fingerprint Deposits.
`
`J Phys D, 1975, V8, p724, pptO.
`
`Thomas G L.
`
`The Physics of Fingerprints and Their Detection; Review.
`
`J Phys E, 1978, V11, p722, pp10.
`
`Wilson J D, Darke D J.
`
`The Analysis of the Free Fatty Acid Components of Fingerprints.
`
`Harwe/l Ind Report, AERE rep G984, 1977.
`
`Wilson J D, Darke D J.
`
`The Results of Analyses of the Mixtures of Fatty Acids Found on the Skin;
`
`Part 1:- Commentary.
`Part 2:— Results and Tables.
`
`Harwell Ind Hepon‘, AERE rep G1154, 1978.
`
`PSDB March 1998
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`

`l ll l l l
`
`.
`
`.
`
`24
`
`EFFECTIVE IMPLEMENTATION OF TECHNIQUES
`
`Chapter 2
`
`2.6
`
`2.6.1
`
`PHOTOGRAPHY
`
`Introduction
`
`This section is not a complete guide tO the photography Of fingerprints but
`draws attention to some important aspects. Further comments are included in
`EXAMINATION AND PHOTOGRAPHY OF FINGERPRINTS (Section 9) in each of the
`process instructions Of Chapter 4.
`
`The final result Of most successful fingerprint examinations is a photograph or,
`increasingly, a digital image. Attention to the photographic techniques used is
`therefore as important as the correct choice and use Of
`the fingerprint
`development processes. All photography and printing Of fingerprints should be
`carried out to a high standard otherwise important detail may be lost.
`
`Fingerprints which are found to be just insufficient for identification purposes
`should be re-examined to determine whether improved photography could
`make them identifiable.
`
`Adequate depth Of field and sharp focus are particularly important during bOth
`
`the photography and printing stages.
`
`Fixed-focus cameras may be used at scenes of crime or in conjunction with
`fixed lights and a copy stand in the fingerprint laboratory. This can make the
`photography and subsequent
`printing Of
`large numbers Of developed
`fingerprints rapid and precise.
`
`fingerprint being
`Determining the exposure will depend on the type Of
`photographed. For some types Of fingerprint automatic or semi-automatic
`exposure systems are effective.
`
`Electronic digital imaging Offers many advantages in the fingerprint laboratory.
`in particular it enables developed fingerprints to be recorded at various stages
`during sequential treatments. it also allows the image quality to be monitored
`immediately and the image may then be downloaded directly into an automatic
`fingerprint searching system.
`
`Some developed fingerprint images will fade. This is particularly noticeable
`with VACUUM METAL DEPOSITION developed fingerprints which can disappear
`within a few hours. NINHYDRIN fingerprints can fade, unpredictably, over a longer
`period. These
`fingerprints must
`be
`photographed
`immediately
`after
`development.
`
`When a sequence Of processes is being used all useful fingerprints should be
`photographed at each stage since a subsequent process may destroy them.
`
`PSDB March 1998
`
`2.6.2
`
`Selection of film type
`in conventional photography a combination Of emulsion and reduction ratio
`must be selected to give sufficient definition or resolution for the fingerprint
`expert to make an identification. Reduction ratios Of 1:2 or 1:3 may be achieved
`with reasonable image quality with fine grain emulsions but any reduction in
`image size inevitably leads tO some loss of information.
`
`A fine-grain, medium to high contrast, panchromatic black and white film, such
`as Kodak T—Max 100 and 400, T400 CN, Technical Pan 2415,
`llford Delta 100
`and 400 or XP2, is suitable for most fingerprint photography. The choice Of film
`will in some cases be limited by the format.
`
`films can be altered by different
`index characteristics Of
`The contrast
`developers and development procedures tO suit
`the individual application.
`There are also occasions when very high contrast lithographic films such as
`Kodak OrthO Type 3 may be required, e.g. when recording the very faint
`
`

`

`Chapter2
`
`EFFECTIVE IMPLEMENTATION OF TECHNIQUES
`
`25
`
`fingerprints that are sometimes developed with SUDAN BLACK, VACUUM METAL
`DEPOSITION and GENTIAN VIOLET.
`
`There are advantages in restricting the types of film to a minimum compatible
`with the technical
`requirements
`so that
`the photographer can become
`thoroughly familiar with their characteristics and produce consistent results.
`
`if fingerprints are visible which have a particularly wide brightness range with
`very dark and very light areas, films should be developed to moderate, or even
`low,
`rather than high, contrast. This is essential
`to prevent parts of
`the
`fingerprint not being recorded because they are below the threshold of the film
`sensitivity.
`
`imaging standard
`Digital
`the
`recording all
`imaging system must similarly be capable of
`A digital
`information needed by a fingerprint expert to make an identification. There is
`no simple relationship between the performance of digital
`imaging systems
`and conventional film and standards for digital imaging are only just emerging.
`It is likely that high quality CCD arrays in combination with high definition lenses
`will
`record sufficient
`information
`for
`fingerprint
`identification
`if,
`using
`monochrome cameras, without compression, there are at least 500 pixels per
`inch or approximately 20 per mm and an 8 bit greyscale is captured.
`
`2.6.3
`
`2.6.4
`
`Colour filtration
`
`The benefits of using colour filtration can be dramatic. This subject is complex
`and many different combinations of film, filter and lighting are possible. Film
`and filter manufacturers'
`literature and standard photographic textbooks
`provide useful
`information for anyone using specialised colour filtration. An
`understanding of the spectral sensitivity of films, the spectral output of different
`light sources and the transmission characteristics of
`filters
`is
`invaluable.
`Examples follow of some of the many situations in which colour filtration can
`prove beneficial.
`
`lf fingerprints which are dark in colour are to be photographed on a dark
`coloured background,
`the use of a suitable filter to lighten the tone of the
`background may improve the contrast. An example of this would be fingerprints
`developed with GENTIAN VIOLET on a green background. The contrast would be
`enhanced by photography through a green filter.
`
`It is also possible to reduce the effects of some printed text or patterns on a
`background. For example fingerprints developed with SMALL PARTICLE REAGENT
`or VACUUM METAL DEPOSITION on a white plastic bag with red printing. A red
`transmitting filter will reduce the distracting detail of the printing and enhance
`the legibility of the fingerprints.
`
`for example the contrast
`In other cases the opposite effect may be utilised,
`between a white powdered fingerprint and an orange surface could be
`enhanced by using a green filter. Other more specialised filtering techniques
`may be applicable to some multicoloured surfaces.
`
`PSDB March 1998
`
`
`
`
`
`
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`

`

`26
`
`EFFECTIVE IMPLEMENTATION OF TECHNIQUES
`
`Chapter 2
`
`2.6.5
`
`2.6.6
`
`2.6.7
`
`Lighting
`The lighting of fingerprints is critical and can make dramatic differences to the
`quality of
`the final photograph or digital
`image. Most fingerprints can be
`photographed under diffuse, even illumination but some are better illuminated
`by transmitted light, specular lighting or low angle oblique lighting.
`
`In some cases the same fingerprint can appear lighter or darker than the
`background depending on whether diffuse, specular or transmitted light
`is
`used. Polarising filters can be used to reduce specularly reflected light when
`this presents a problem.
`
`It is important that a wide range of appropriate types of illumination system is
`available to the photographer.
`
`An alternative to the use of individual filters is precise control of the wavelength
`of the illuminating light. A monochromatic light source can be used in some
`cases to produce dramatic
`improvements
`in
`contrast when
`coloured
`fingerprints are present on a slightly different coloured background.
`
`The lighting must be appropriate to the spectral sensitivity of the film. This is, of
`course, crucial
`it correct colour rendition is required when photographing in
`colour but
`it
`is also important when using a black and white film with an
`unusual colour
`response. For example,
`infrared reflectance photography
`requires a source with high infrared emission such as a tungsten filament lamp.
`
`Printing
`It is important to use a high grade enlarging lens in good condition. A diffuser
`tungsten, or cold cathode, enlarger will give a print of
`lower contrast and
`definition than that obtained with a condenser enlarger; although the latter is
`now rarely available.
`
`It is also possible in some cases to photograph directly onto paper to reverse
`the tone, however
`the original must have good contrast.
`In particular,
`fingerprints developed with ALUMINIUM POWDER are usually recorded this way.
`
`FLUORESCENCE EXAMINATION, VACUUM METAL DEPOSITION and some other
`techniques also produce fingerprints with reverse tone,
`i.e. white ridges on
`black background. These can be reversed photographically by producing an
`intermediate negative, by reversal processing of film or by printing on reversal
`paper such as Kodak Transtar TPP5.
`
`Other photographic techniques
`in
`FLUORESCENCE EXAMINATION can often produce dramatic improvement
`contrast. The specific techniques are described in FLUORESCENCE EXAMINATION
`(Chapter 4, Process Instructions, Section 9). There are other specialised
`techniques which may occasionally be
`useful
`including
`dark ground
`illumination, on-axis
`illumination, peripheral photography and ultraviolet
`photography;
`these techniques are discussed in
`standard textbooks of
`photography.
`
`PSDB March 1998
`
`
`
`
`

`

`Chapter 2
`
`EFFECTIVE IMPLEMENTATION OF TECHNIQUES
`
`27
`
`. 2.6.8
`
`Bibliography
`Clerc L P.
`Photography Theory and Practice.
`Book, Pubiished by Focal Press Ltd, 1972.
`ISBN O~240-50774—6
`
`.
`
`.
`
`Cowger J F.
`
`Friction Fiidge Skin.
`
`Book, Pubiished by EIsevier, 1983, p111, pp18.
`ISBN 0~444~OO770-9
`
`Filters.
`
`Book, Published by Schiele & Schon, Berlin, 1979.
`ISBN 3-7949-0340-4
`
`Hardwick S A, Kent T, Sears V G.
`
`Fingerprint Detection by Fluorescence Examination.
`
`Book, Pubiished by the Home Office, UK, 1992.
`ISBN O-86252~554-3
`
`I/ford Technical information Booklets.
`
`IIford Ltd.
`
`14-22 Tottenham Street,
`London W1 P OAH.
`
`Jacobson R E.
`
`The Manual of Photography.
`
`Book, Published by Focal Press Ltd, 1978.
`ISBN 0-240-50957-9
`
`Kodak information Sheets.
`
`Kodak Ltd.
`
`PO Box 66,
`
`Kodak House, Station Road,
`
`Hemel Hempstead,
`Herts. HP1 1JU.
`
`Olsen Sr R D.
`
`Scott's Fingerprint Mechanics.
`
`Book, Published by C C Thomas, 1978, p409, pp15.
`ISBN 0-398-03730-2
`
`Pfister R.
`
`The Optical Revelation of Latent Fingerprints.
`
`J Forens Sci Soc, 1984, V24, N04, p303, pp1.
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`28 EFFECTIVE IMPLEMENTATION OF TECHNIQUES
`Chapter 2
`
`Rason J J, Miller J F, Patton C B.
`
`Digital Imaging of Scene of Crime Fingerprints System Requirements and Image Quality.
`
`Proceedings of the International Symposium of Fingerprint Detection and Identification,
`Israel, June 1995.
`
`Rason J.
`
`Latent Fingerprint Digital Image Capture and Quality Standards.
`
`Proceedings of the IEE European Conference on Security, Brighton, May 1995.
`
`
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`VISUAL EXAMINATION
`
`
`
`The detection of fingerprints by close visual examination should always be
`carried out before subjecting articles to any fingerprint development technique.
`Any useful
`fingerprints
`should be photographed before proceeding with
`subsequent processes since some fingerprints may not be detected by any
`other means. Good natural and artificial lighting is essential.
`
`A visible fingerprint on a compact disc
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`VISUAL EXAMINATION
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`Chapter 4
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`VISUAL EXAMINATION
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`PFOCeSS name .
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`MAY BE USED ON:
`
`All surfaces.
`
`NOT SUITABLE FOR USE ON:
`
`Not applicable.
`
`ADVANTAGES
`
`Simple visual examination and photography are normally non-destructive but
`lifting and casting (see Section 10) may destroy visible or latent fingerprints.
`
`DISADVANTAGES
`
`Requires good lighting and considerable care to carry out a thorough and
`effective examination.
`
`CAN INTERFERE WITH FORENSIC EXAMINATION FOR:
`
`Simple visual examination and photography will not normally interfere with any .
`specific forensic procedures; however, it is important not to lose trace evidence
`and avoid cross-contamination. Lifting and casting (see Section 10) may
`remove trace evidence and contaminate the article.
`
`SAFETY REQUlREMENTS
`
`Not applicable.
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`Chapter 4
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`\HSUALEXANHNATKDN
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`3
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`USE OF PROCESS
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`Refer to EQUIPMENT (Section 11) as necessary.
`
`7.1
`
`Introduction
`
`Careful examination of articles may reveal fingerprints already visible before
`any development treatment has been carried out. These fingerprints must be
`photographed before proceeding since they may disappear during subsequent
`treatment.
`
`Various types of fingerprint may be visible; they may be:
`
`Type 1
`
`in a transparent material such as sweat, oil or grease;
`
`Type 2
`
`in a coloured material such as blood, ink or paint;
`
`Type 3
`
`in dust;
`
`Type 4
`
`the result of a reaction between a fingerprint and the surface, eg. fingerprints
`visible on ferrous and silver articles as a result of surface corrosion or
`
`tarnishing;
`
`Type 5
`
`impressions in a soft material such as wax or putty.
`
`72
`
`STEP 1
`
`The VISUAL EXAMINATION of articles and surfaces
`
`Examine article or surface for any indication of fingerprints. Make full use of
`any daylight available and use lamps when necessary to ensure that the
`surface is well illuminated.
`
`Turn small articles or move lamp around to change angle of illumination. Some fingerprints can be seen
`clearly only by oblique lighting. Choice of lamp can significantly affect success:
`ideally a high level of
`even illumination is required avoiding direct or indirect glare from the light source.
`Extreme care is needed when handling articles not to damage other fingerprints which may not yet be
`apparent (see Handling and packaging of exhibits, Chapter 2, Section 2.5).
`
`STEP 2
`
`Photograph useful fingerprints (see Section 9).
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`EXAMINATION AND PHOTOGRAPHY OF FINGERPRINTS
`Some fingerprints already visible may be photographed easily, but Types 1, 3,
`and 5 may prove difficult to photograph and have to be illuminated with care.
`
`.
`
`These latter types are often best photographed by scattered light resulting from
`oblique illumination. This can be conveniently provided with a fibre optic or
`liquid light guide.
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`Chapter 4
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`10
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`Type 1
`
`Type 2
`
`Type 3
`
`WSUALEXANHNAHON
`
`5
`
`FURTHER ENHANCEMENT OF FINGERPRINTS
`Techniques for
`improving any visible fingerprints depend on the type of
`fingerprint (Section 7.1) as follows:
`
`proceed according to the most appropriate of the PROCESS SELECTION CHARTS
`in Chapter 3;
`
`in other
`if
`is in blood, proceed in accordance with CHART 12.
`if fingerprint
`material, proceed with treatments according to the chart appropriate to surface;
`
`fingerprints which are in a layer of dust, or which have picked up dust since
`they were deposited, should normally be photographed in situ.
`If they are
`difficult to photograph there may be some benefit in lifting them.
`
`A decision will have to be made whether to lift a fingerprint or to proceed with a
`treatment in accordance with the relevant PROCESS SELECTION CHART. Lifting
`may damage fingerprints which are not yet visible.
`
`There are two simple ways to lift a fingerprint in dust:
`
`i)
`
`with a transparent lifting tape, as in Section 7.2 of the process instructions
`for POWDERS. When the tape has been lifted from the surface it may be
`applied to a backing sheet which is transparent, white or black depending
`on the colour of the dust. Lifting may not always be very effective because
`of the low contrast sometimes obtained when the dust is absorbed into
`the adhesive.
`
`ii)
`
`with a black or white opaque lifter. This is often more effective than
`transparent tape and better contrast is usually obtained;
`
`Type 4
`
`Type 5
`
`proceed according to the most appropriate of the PROCESS SELECTION CHARTS
`in Chapter 3;
`
`normally be
`such as putty should
`impressed in materials
`fingerprints
`photographed in situ.
`if they are difficult to photograph it may be possible to
`cast replicas. Various casting compounds are suitable and should be used
`according to the manufacturers' instructions. The casts may be improved by the
`careful application of a black fingerprint ink or similar material with a roller.
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`11 EQUIPMENT =>
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` 6 VISUAL EXAMINATION Chapter 4
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`
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`11
`
`11.1
`
`EQUIPMENT
`
`Introduction
`
`This section lists equipment which has been found suitable for carrying out this
`process and is a guide to manufacturers and suppliers. There are other
`companies which may be able to supply similar articles at comparable prices
`and police forces are recommended to obtain competitive tenders when
`appropriate. In most cases It is essential that goods supplied are of high quality
`and of equivalent specification to those listed.
`In cases of doubt PSDB may be
`able to provide a more detailed technical specification. Quantities where given
`are the suggested minima for carrying out the process. In many cases it is left to
`the discretion of the purchaser.
`
`Ensure that adequate supplies of protective clothing and equipment are
`available. Some equipment may have been purchased already for other
`processes: avoid unnecessary duplication.
`
`11.2
`
`Equipment (see Appendix II for list of suppliers)
`ITEM
`
`QUANTITY SUPPLIERS
`
`Acetate sheets
`
`Fibre optic cold light lllumlnator
`
`Fingerprint ink
`
`Lamp, scene of crime
`
`Lifting tape
`
`Light box
`
`Opaque lifters
`Rollers
`
`Silicone rubber
`
`14,31 ,40,48,54
`
`27,30
`
`14,31 ,48,54
`
`50,52,56,57
`
`14,38,39,46,48,54,
`58,72
`
`61 ,62,63
`
`14,31 ,48,54
`14,31 ,54
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`Cowger J F.
`Friction Ridge Skin.
`Book, Published by Eisevier, 1983, p73, pp3.
`ISBN 0-444-0770-9
`
`Olsen Sr R D.
`
`Scott’s Fingerprint Mechanics.
`Book, Published by C C Thomas, 1978, p406, pp12.
`ISBN 0-398-03730-2
`
`Pfister R.
`
`The Optical Revelation of Latent Fingerprints.
`J Forens Sci Soc, 1984, V24, N04, p303, ppt.
`
`Pfister R.
`
`The Optical Reveiation of Latent Fingerprints.
`Fingerprint Whor/d, 1985, Jan, p64, pp7.
`
`Chapter 4
`
`VISUAL EXAMINATION
`
`12
`
`BIBLIOGRAPHY
`
`7
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