Forensic Photography E-Book

Nick Marsh

• Herausgeber: John Wiley & Sons
• Kategorie: Fachliteratur
• Sprache: Englisch

Seitenzahl: 674

Veröffentlichungsjahr: 2014

Beschreibung

Forensic photography plays a vitally important part in the investigation of crime and the subsequent administration of justice. Written by a practitioner with many years professional experience, this book provides an overview of the most common forensic photography techniques in use today for those readers who may not have a detailed understanding of camera techniques and who need to get to grips with the use of light and other key scientific aspects of the job. It covers image capture issues, file handling and relevant equipment, such as lasers and UV lights, and explores how they work.

The predominance of the digital camera has resulted in an increasing trend for police forces across the world to use untrained camera users, rather than expert photographers. Therefore, this book will prove invaluable for those practitioners who need to produce accurate and clear photographic evidence, above and beyond the point and shoot mode on their cameras. 

Leseprobe

Forensic Photography

A Practitioner's Guide

Nick Marsh

Consultant Forensic Practitioner, UK

This edition first published 2014 © 2014 by John Wiley & Sons, Ltd

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CONTENTS

Foreword

Preface

Acknowledgements

About the Companion Website

Chapter 1: Image Processing

1.1 Introduction

1.2 The digital image

1.3 Image acquisition

1.4 Colour images

1.5 The imaging chain and workflow

1.6 White balance

1.7 Image histogram

1.8 Image processing terminology

1.9 Digital image processing operations

1.10 Classes of operations

1.11 Noise reduction

1.12 Sharpening filters

1.13 History log

1.14 Layers

1.15 Bit depth and dynamic range

1.16 File formats

1.17 Image compression

1.18 Image processing at image capture

1.19 Properties of common formats

1.20 Image archiving and the audit trail

1.21 Printing images

1.22 Image storage

1.23 Summary

Notes

Chapter 2: Cameras and Lenses

2.1 Overview

2.2 Cameras

2.3 Exposure

2.4 ISOs

2.5 The shutter

2.6 F-stops and apertures

2.7 So what is the correct exposure?

2.8 Metering modes

2.9 Getting the right exposure

2.10 Dynamic range

2.11 Depth of field and focus

2.12 Lenses

Reference

Notes

Chapter 3: The Use of Flash

3.1 How does it work?

3.2 Guide numbers

3.3 Flash modes

3.4 The inverse square law (ISL)

3.5 The practical application of flash

3.6 Types of flash

Chapter 4: Crime Scene Photography

4.1 Overview

4.2 Personal protective equipment (PPE)

4.3 The generics of scene photography

4.4 Photographic equipment

4.5 Composition

4.6 Specific types of scenes

4.7 Appendix 1: Trouble-shooting

References

Notes

Chapter 5: Light as a Forensic Photographer's Tool

5.1 Overview of alternative light sources (ALS)

5.2 The Electromagnetic Spectrum (EMS)

5.3 Fluorescence

5.4 Alternative light sources

5.5 Filters

5.6 Infrared (IR)

5.7 White light

5.8 Conclusion

References

Notes

Chapter 6: The Photography of Injuries

6.1 Overview

6.2 The nature of injuries

6.3 The photography

6.4 Before we start

6.5 Techniques and equipment required

6.6 The colour reference

6.7 Reflected Ultraviolet (UV)

6.8 Lenses

6.9 Lighting

6.10 Capturing the image

References

Further useful reading

Notes

Chapter 7: Finger and Shoe Mark Photography

7.1 Overview

7.2 The nature of finger marks

7.3 Shoe marks

7.4 Equipment

7.5 Lighting techniques

7.6 Chemically enhanced marks

7.7 Latent marks

7.8 Shoe marks

7.9 Tyre marks

7.10 Blood enhancement techniques

References

Notes

Chapter 8: The Proactive Use of Light in Forensic Photography

8.1 Overview

8.2 The detection of body fluids using an alternative light source

8.3 Inks

8.4 Sign writing

8.5 The detection of blood

8.6 Luminol

8.7 Other uses of Infrared (IR)

References

Notes

Chapter 9: Specialist Equipment and Techniques

9.1 Peripheral cameras

9.2 Object modelling

9.3 Multi-spectral imaging camera

9.4 High speed imaging

9.5 UVC photography

References

Notes

Chapter 10: Panoramic (Immersive or 360°) and Elevated imaging

10.1 Overview

10.2 Spheron

10.3 Digital Single Lens Reflex 360°

10.4 Elevated imaging

Reference

Notes

Appendix 1: Tripods and Camera Supports

A.1 Tripods

A.2 Scene tripods

A.3 Other types of camera platforms

A.4 Video tripods

A.5 Other types of clamps

Notes

Index

End User License Agreement

List of Tables

Chapter 2

Table 2.1

Chapter 6

Table 6.1

List of Illustrations

Chapter 1

Figure 1.1 Left: Image of object (smooth edges, continuous tone) projected onto array of square pixels. Right: digitised image after sampling and quantisation. Sampling leads to ‘blocky’ edges; quantisation produces discrete levels of grey and leads to blurred edges because the resulting grey level is a function of the average intensity at each pixel.

Figure 1.2 Images of finger mark, recorded with bit depths of (left) 8, (middle) 2, and (right) 1, giving 256, 4 and 2 grey levels respectively. In order for us to perceive a monochrome image as having continuous tone, 8-bits are required, allowing 2

8

, that is 256, discrete values or grey levels. I will discuss file formats later in the chapter but it is worth noting here that different file formats may have, or allow, different bit depths. It is common for raw formats to utilise 10, 12 or 14 bits; TIFF may allow 8 or 16 bits, whilst JPEG is limited to 8 bits. Are extra bits necessary if we can't perceive the difference between several different values? Maybe (more on this later).

Figure 1.3 A typical Bayer colour filter array, laid over the sensor, means that each pixel only records part of the colour spectrum (left); full colour information for each pixel results from demosaicing (right).

Figure 1.4 A typical imaging chain and workflow.

Figure 1.5 Colour scales (and linear scales) provide standard references, against which objects in the image may be compared.

Figure 1.6 (a) Dark, low contrast image and associated histogram. (b) Low contrast image and associated histogram. (c) Bright, low contrast image and associated histogram. (d) High contrast image and associated histogram.

Figure 1.7 Use of levels function. (a) The image as captured and the associated histogram. (b) Image processing using the level to enhance contrast and associated histogram.

Figure 1.8 (a) Original image and histogram. The point in the image chosen to represent a neutral grey is indicated here by an ‘X’, near the centre of the image. (b) Image and histogram after colour adjustment using the grey picker.

Figure 1.9 The digital image as an indexed two-dimensional array of values, showing pixel location.

Figure 1.10 Image cropping. An area is selected and the rest of the image is cropped out leaving the remaining portion unchanged.

Figure 1.11 Image resampling. In this example, the image is resampled from 8 × 6 pixels to 5 × 4 pixels; every pixel value must be recalculated, resulting in increased blockiness and blurring.

Figure 1.12 Image rotation. The image (top) is rotated clockwise by approximately 30° (middle) and resampled to fit the rectangular matrix (bottom image), resulting in increased blockiness and blurring.

Figure 1.13 Photoshop's crop tool allows resampling, resizing, rotation and perspective correction to be performed all together. Image (top) suffers from perspective distortion and is not at a scale suitable for comparison. The user may select the desired output size and resolution before placing and dragging a box (middle, highlighted section), which then becomes the output image (bottom). In this example the perspective correction is only approximate; it would have been much better to have included a second L-shaped scale to fully bound the mark, allowing reliable and accurate correction.

Figure 1.14 Addition. Top: image of grey scale, graph of input pixel values versus output pixel values and associated image histogram before simple brightness adjustment. Bottom: resulting image of greyscale, graph of input pixel values versus output pixel values and associated image histogram after simple brightness adjustment (lightening). Note the loss of discrimination in the highlight region.

Figure 1.15 Subtraction. Starting from the same point as in figure 1.14, top, above: resulting image of greyscale, graph of input pixel values versus output pixel values and associated image histogram after simple brightness adjustment (darkening). Note the loss of discrimination in the shadow region.

Figure 1.16 Noise reduction with blur filter. Top: image of finger mark, which exhibits contouring and noise as a result of extreme contrast enhancement. Bottom, left: close up of section indicated by white box. Bottom, right: same area after simple blur filter. Note: the original image was captured in JPEG format, which accounts for the poor quality. The amount of blur can be increased by either applying the same process multiple times or by increasing the size of the neighbourhood (group) to, say, five by five or seven by seven pixels.

Figure 1.17 Images of a 2 cm

2

section of a footwear mark. Left: before sharpening; middle: after USM, amount 100, radius 1.5, threshold 0; right, after USM, amount 200, radius 5.0, threshold 0.

Figure 1.18 Scene dependency. Top row, left: finger mark on noisy background; middle: after a medium amount of blurring; right: after a medium amount of sharpening. Bottom, left: finger mark on plain background; middle: after a medium amount of blurring; right: after a medium amount of sharpening. The amounts of blurring and sharpening in each example are similar. Note how the visibility of finger mark ridges is improved by a different filter in each case.

Chapter 2

Figure 2.1 Photographic illustration of ‘k’. (a) A Cambo 5 × 4 camera demonstrating the separate movement of the front lens panel and the rear film plane. (b) The image projected onto the rear ground glass focusing screen.

Figure 2.2 Illustration of sensor sizes. Note, even with APS there are differences in size between manufactures.

Figure 2.3 An old style lens resolution chart produced in the 1980s taken on a Nikko

r

105 mm macro lens. On the right you can see an enlargement showing 60 and 80 line pairs.

Figure 2.4 The common camera mode settings available on most digital cameras.

Figure 2.5 A Nikkor 50 mm 1.8 lens with the diaphragm in various aperture settings. Note that opening or closing the lens by one stop will double or halve the light passing through the lens. For example, changing the aperture from f8 to f5.6 will let twice the amount of light in, whereas changing it from f8 to f11 will halve the light passing through the lens.

Figure 2.6 shows the use of the aperture to control the depth of field. (a) The aperture wide open at f2.8. (b) The aperture closed to f22.

Figure 2.7 (a) Our set amount of light represented by a ball of plasticine. (b) The plasticine flattened to produce a large flat disk, representing a large aperture but shallow depth of field. (c) The plastic rolled into a sausage shape, representing a small aperture and large depth of field.

Figure 2.8 An example of hyperfocal distance. (a) Focused using the hyperfocal distance (note that all the letters are acceptably in focus). (b) Focused on infinity, although the letters Z, Y and X are acceptably sharp, W and V are both soft.

Figure 2.9 In this example of zone focusing we can see that the markers are in focus but infinity is not. (In this case infinity is indicated by the tree line.)

Figure 2.10 The depth of field using a Nikkor 105 mm lens as it is stopped down, note that the angle of the scale is approximately 45° to the camera.

Figure 2.11 A 300 mm lens fitted in (a) to a FX sensor and in (b) to a DX sensor, increasing its focal length to 450 mm.

Figure 2.12 An 18 mm to 135 mm DX lens, set to 18 mm, fitted to a FX sensor. Here we can see severe vingnetting around the edge of the image, where the coverage of the lens was not sufficient to cover the whole of the sensor surface. This effect can also sometimes be seen to a lesser effect when wide-angle lenses are fitted with lens hoods.

Figure 2.13 A range of focal lengths. Note the decreasing angle of view as the focal length of the lens is increased.

Figure 2.14 A set of manual bellows fitted to a macro Nikkor 60 mm lens.

Chapter 3

Figure 3.1 Illustration of a flash unit; image courtesy of Colin Inglis, Suffield Imaging.

Figure 3.2 (a) The sync speed incorrectly set to 1/500th at f11. Across the bottom of the image we can see that the vertical shutter blades of the camera have not fully opened. (In older cameras, with curtain shutters, this unexposed area would run horizontally across the frame rather than vertically as in the example.) (b) The sync speed set to 1/125th at f11.

Figure 3.3 Here although the flash has provided the main exposure for the manikin, Greg's arm has also been exposed because the shutter was accidently set to half a second, and the ambient light generated by the modelling lights has exposed his arm causing it to appear in a ghost like fashion.

Figure 3.4 Here we can see the back of a generic type flash unit. Although each manufacturer has a slightly different layout, all display the same key features. (a) Shows that the head can be angled by set degrees allowing it to be bounced off the ceiling. (b) Shows that the head can be rotated in either direction allowing the flash to bounce off walls or other surfaces (c) Shows that the flash can fire at the end of the exposure ‘rear’ setting, or at the beginning ‘normal’ setting. (d) Shows the display readout. This one is digital display, many use a dial system, but both give the same information. (e) Shows the flash control panel; the orange light shows the flash is charged and ready for use. (f) Shows the function button for ‘A’ automatic, ‘M’ manual, three ‘lighting flashes’ strobe, ‘TTL’ Through The Lens metering.

Figure 3.5 A typical digital flash display. (a) Function setting ‘M’ manual. (This would show ‘A’ for automatic and ‘TTL’ for Through The Lens.) (b) ISO 160 setting (when attached to the camera this will automatically change with the camera). (c) Distance and flash range indicated by the black bar. (d) Flash zoom setting (when attached to a dedicated camera fitted with a zoom lens this will automatically change as the lens is zoomed). (e) F-stop value. (f) Flash power 1/1 indicates full power.

Figure 3.6 Changing the aperture.

Figure 3.7 Change of zooming factor.

Figure 3.8 The impact of changing the ISO.

Figure 3.9 Photographing an exhibit using a 50 mm lens and the camera set to ISO 200. The flash is set to full power, giving us a guide exposure of f11 at 4 metres.

Figure 3.10 Adjustments to the output power at 3 m, 2 m, 1.5 m, and 1 m.

Figure 3.11 Shows an exhibit photographed from about 2.2 m. (a) With the flash on

1

/

2

power at f11, overexposing the exhibit. (b) The same exposure, this time with single layer of hanky over the flash head. Clearly a reasonable compensation in exposure can be achieved in post-production; however, depending on the circumstances this is not always practical. It is therefore good practice to get the exposure right in camera when you, the photographer, are in control.

Figure 3.12 Diagram showing inverse square law flash fall off.

Figure 3.13 An example of strobe being used to illuminate a partial shoe mark on a tiled floor, using the strobe as specular illumination. Here the strobe was set to 8 flashes of 9 Hz at f13, with the shutter opened for 3 seconds.

Figure 3.14 (a) The area of fire damage and lack of ambient illumination. (b) In this case I was able to use the arm and seat of the chair as a point of contrast to allow visual focusing. The other alternative would have been to use zone focusing by setting the distance on the lens. Don't forget that you can zoom in if you are using a zoom lens to focus and then zoom out when you are ready to take the shot.

Figure 3.15 Flash on camera creating deep shadows from the doorframe.

Figure 3.16 As Figure 3.15 but this time two guns have been used. The diagram shows the approximate angle and direction of the flash.

Figure 3.17 (a) The approximate ambient lighting conditions; the only light was a small interior light in the house, to the left in image. (b) One flash mounted on camera held beside the camera; this produces a reasonable exposure, but suffers from fall off behind the car and to the right hand side. (c) Multiple flash exposures around the camera; this produces a well-illuminated image with the car light from all angles. The important thing to remember is: what are we trying to achieve? Are we trying to capture the lighting, as, say, in the case of a fatal accident, when image (a) might be applicable? Or are we trying to see the scene so that all the evidence is visible, where image (b) or (c) might be the correct lighting?

Figure 3.18 shows an exterior shot of a car in position. The camera is set to f8 at 400 ISO. (a) 30-s exposure showing the ambient lighting conditions. (b) 2-min exposure (camera set to bulb) lit with five flashes on full power. (c) Approximate position of the flash. Note that I have slightly changed the camera position in (b) to include more of the drive.

Figure 3.19 A number of open flash faults. First we have the typical flash into camera; here it has been accidently pointed towards the camera on the extreme left and right, producing a starburst effect. This effect is often seen when small apertures and street lighting come together for long exposures and is formed by the aperture diaphragm. Second, the small green and red warning lights on the back of the flash can be seen, leaving long trails. It is a good idea to shield these with your body when moving around the scene within the viewpoint of the lens. Third are the unwanted and unintentional interventions of third parties, here it is Harvey our labrador who, just like any police office or bystander, is interested in what is going on.

Figure 3.20 A basic studio lighting set up using four studio flashes, two fitted with soft boxes and two with umbrellas.

Figure 3.21 A digital flash meter showing a reading of f11.6 at 100 ISO.

Figure 3.22 You can see in this illustration that I am using the corner of an office to photograph a blood-stained kettle. This has been laid out on brown paper, which I have taped to the side of a desk, acting as a basic infinity curve. Because the exhibit was on the floor I could simply have shot straight down. However, as the exhibit was a kettle, this did not look right when viewed through the viewfinder. I therefore decided to take it at ground level by mounting the camera on a gorilla pod. I originally photographed it from the front with two flash guns, however the shadows were harsh and strong so I changed the exposure to an open flash one. The lights were switched off and the camera set to a 20-s exposure, which was enough to allow me to fire the flash four times to illuminate the front, sides and behind the kettle.

Figure 3.23 A room scene photographed using four different lighting techniques. (a) Under ambient lighting f11, 1/5th 800 ISO. (b) Using a fill in flash hidden around the corner of the right hand wall triggered by a flash slave unit, f11, 1/5th 800 ISO. (c) The room light with flash only f11, 20 s 800 ISO. (d) The room lit with only a torch ‘painting with light’ f11, 1 min 400 ISO. Note that the result in (d) leaves a slightly blotchy effect on the walls if the beam is too focused if kept in one place for too long.

Figure 3.24 Sigma ring flash.

Figure 3.25 Here we can see a studio flash fitted with a soft box being used to illuminate a piece of clothing prior to IR photography.

Figure 3.26 (a) shows the area exposed for the surrounding area, with the interior of the shed in deep shadow. (b) shows the interior exposed for the marker, but note how the foreground is now overexposed losing all highlight detail. (c) shows the same area this time using a single Metz 45 to throw light into the back of the shed.

Chapter 4

Figure 4.1 (a) Shows full PPE used for scenes and (b) the PPE for use within the DNA laboratories.

Figure 4.2 Photographic illustrations of white and black gloves under UV.

Figure 4.3 Lightweight aluminum stepping plates, note the feet can be unscrewed for easy cleaning and, when stacked, the feet slot into the plate below.

Figure 4.4 Here the distracting shadow has been removed, by shielding the area and using off-camera flash.

Figure 4.5 A toy sword with and without a scale.

Figure 4.6 Here we can see the same view of our mock decapitation taken with a 50 mm (a) and 24 mm (b) lens. Although both images are acceptable as an overview, only image (a) has the correct perspective.

Figure 4.7 Here we can see the same choice of lens as in Figure 4.6. However this time, the change in perspective has grossly exaggerated the distance to the road junction, so that we now appear twice as far away as with the standard lens.

Figure 4.8 Shows view looking north along Ford Lane towards Aveley Lane from telephone pole 4. (Exposed at f9.5 at 1/180th 320 ISO.)

Figure 4.9 shows view looking north along Ford Lane towards Aveley Lane from lamppost 23234 (seen in previous photograph). (Exposed at f9.5 at 1/180th 320 ISO.)

Figure 4.10 Show the intersection of Ford Lane, Middle Bourne Lane and Aveley lane. (Exposed at f9.5 at 1/180th 320 ISO.)

Figure 4.11 (a) The Mall looking west toward Buckingham Palace, from the pedestrian island to the west of Spring Gardens SW1. (50 mm lens exposed at f18 1/500th at 400 ISO.) (b) The Mall looking east towards Admiralty Arch from the pedestrian crossing to the west of Spring Gardens SW1. (50 mm lens exposed at f18 1/200th at 400 ISO.)

Figure 4.12 Converging verticals, photographed with a standard lens and then with a shift lens. Although only a minor issue, for our purposes it can be distracting.

Figure 4.13 Angles of view. Again, although the angle isn't a major issue, simply changing position has allowed the frontage of the building to be more clearly seen. This can be particularly seen on the lower photograph where the bushes and tress have blocked the view of part of the ground floor exterior.

Figure 4.14 (a) The exhibit's relationship to both a forensic marker and non movable item (the building). (b) A positional shot of marker ‘V’. (c) Close up of the exhibit at marker ‘V’.

Figure 4.15 Poor framing and viewing angles. On the left, the firearm has been positioned poorly in the viewfinder at an angle. On the right, a landscape viewpoint has been chosen, but angled away from the observer.

Figure 4.16 Here the firearm has been correctly positioned so that it is square in the viewfinder with all the detail clearly seen.

Figure 4.17 Photographic illustration of tripod socks.

Figure 4.18 15 mm (fisheye) lens.

Figure 4.19 24 mm lens.

Figure 4.20 35 mm lens.

Figure 4.21 50 mm lens.

Figure 4.22 The entrance to the scene. (a) Illuminated with ambient lighting 400 ISO at f11 1.3 s exposure. (b) With two flash units, one illuminating the doorway one with the diffuser removed fired down the hallway (400 ISO at f11 ¼ s).

Figure 4.23 The kitchen area.

Figure 4.24 The living room area showing a knife.

Figure 4.25 The knife in position.

Figure 4.26 The knife.

Figure 4.27 The bathroom.

Figure 4.28 The view from the bathroom into the living room.

Figure 4.29 The bedroom.

Figure 4.30 The view from the bedroom towards the living room.

Figure 4.31 The front 3/4 of a motor vehicle photographed (a) without fill in flash (b) with fill in flash.

Figure 4.32 Front ¾ of MV using various lenses.

Figure 4.33 Photograph of the damage to car door (a) when viewed square on – notice how the damage looks shallow. (b) As before, but this time photographed from the rear of the car looking forwards, illuminated with flash.

Figure 4.34 Damage to a windscreen. Although both are acceptable (a) shows the unpolarised image, whilst (b) shows the polarised image which appears cleaner and has more contrast, whilst the distracting white paper in the windscreen has been suppressed.

Figure 4.35 Photograph of VIN plate.

Figure 4.36 Photograph of windscreen plate.

Figure 4.37 Window etching (a) with the door open using ambient lighting exposed at f8, 1/30th 400 ISO (b) with the door closed and illuminated with flash from the opposite side of the car, exposed at f8 1/60th 400 ISO, flash set to manual half power. Note in (b) although the etching is legible, the interfering background is distracting. This is often not seen until the exposure has been taken. It is not, however, always possible to remove them if the vehicle is locked.

Figure 4.38 An exhibit photographed packaged and unpackaged.

Figure 4.39 Clothing on a manikin.

Figure 4.40 A comparison between (a) flash on camera and (b) open flash technique. Although both would be acceptable (b) allows the area under the table to be illuminated removing unwanted shadows.

Figure 4.41 The lens manually focused on the electrical elements of a fire damaged electric fire.

Figure 4.42 The same road scene using a 28 mm, 35 mm, 50 mm and 70 mm lens.

Figure 4.43 The full length clothed body taken above the table. This would be repeated for the back and then again when the clothes have been removed. Because we would use a tripod, each image is identically framed, keeping continuity between them.

Figure 4.44 The body photographed from the feet and from the head. Neither viewpoint is useful and both produce distorted and unnatural viewing angles. This also often includes distracting background information.

Figure 4.45 A side view of the body with and without a backdrop. Note that version with the backdrop has also been cropped, removing the superfluous part of the image.

Figure 4.46 Photograph of the body taken under available lighting. The issue to be wary of here is the length of exposure and areas of shadow that may require illumination.

Figure 4.47 Photographs of the face taken with (a) un-polarised flash illumination (b) cross-polarised illumination.

Figure 4.48 (a) shows an injury with no locating points (b) shows an injury in relation to the surrounding area.

Chapter 5

Figure 5.1 The natural fluorescence produced under ultraviolet when you peel an orange.

Figure 5.2 The small visible range of the electromagnetic spectrum plus the ultraviolet and infrared regions, which can be exploited.

Figure 5.3 An item of clothing photographed with studio flash. (a) Shows the white balance set to flash. (b) Shows the cameras white balance set to Tungsten lighting. Failure to colour correct at either the capture or post-production stage can cause numerous issues, as we have seen above. Therefore, if we don't understand this task properly, nobody will.

Figure 5.4 An example of why a number of light sources must be used to ensure all evidence is retrieved. (a) shows an area of wall under white light illumination. (b) shows the same area under a green laser at 532 nm. (c) shows the same area under a yellow laser at 577 nm. Note that even with a small difference of 45 nm the background is suppressed and the mark becomes visible. In (b) we can also see the phenomenon we refer to as ‘the streaky bacon effect’ as it looks just like it. The effect is caused when a thin layer of paint is applied over another layer of paint, which has a stronger autofluorescence, causing it to shine through where the brush has been applied.

Figure 5.5 (a) The absorption of light by the atom causes the electrons to jump to higher state. (b) The emission of light by the atom causing the electron to fall back to its lower state.

Figure 5.6 A simple illustration of Stoke's Shift.

Figure 5.7 Along the top row we can see some test samples (part of a larger study) of a number of well-known types of make-up, applied to different coloured wallpaper surfaces. Below we can see the same samples illuminated by a 532 nm laser. This testing reinforces the impact that the substrate has on any subsequent fluorescence and is why it is important to examine surfaces with as many light sources as possible if you wish to reveal the maximum possible evidence.

Figure 5.8 A contaminated latent mark on a wooden surface. (a) Illuminated with white light, note the background interference from the wood grain. (b)The same area illuminated at 445 nm, note that the wood grain has almost vanished whilst the mark has become much darker. (c) shows a greyscale image of the finished mark, note how although the top part of the mark was visible in photo (a), the core and the delta at the bottom were not.

Figure 5.9 A battery powered Labino in use and a graph showing the emission wavelength, note the strong peak around 365 nm and the small ones from 740 to 848 nm, this accounts for the characteristic red hue that can sometimes be observed.

Figure 5.10 Comparison between the Labino and an alternative UV forensic torch. (a) shows the area under white light illumination. (b) shows the area under an unbranded UV torch; note the overall lack of contrast between the mark and background. This is due to the lamp emitting wavelengths beyond 400 nm. (c) shows the same area under the Labino. (d) shows the area shown within the black square seen on (c).

Figure 5.11 (a) The Tracer 577 nm. (b) The Revelation ‘twin’ 455 nm and 532 nm output laser.

Figure 5.12 The Crime-lite® range. Note that a number of variants are available so it worth visiting the web site for up-to-date information.

Figure 5.13 A 500-W Crimescope CS16.

Figure 5.14 An area of wall illuminated under (a) white light illumination, (b) illuminated with a green laser at 532 nm, and photographed using an ‘orange’ filter, note the lack of contrast and definition within the mark. (c) Shows the same mark, this time photographed using a long band pass 550 nm filter, clearly showing the detail within the mark area.

Figure 5.15 In this simple illustration we can see the excitation light at 365 and fluorescence at 500 nm reaching a long band pass filter at 450 nm. The short wave wavelengths of 365 nm are blocked, but the longer ones at 500 nm pass through (our fluorescence). In reality, some background fluorescence will also pass through but none of the original blue excitation wavelengths should. Indeed, if you can still see any of the excitation illumination through the filter, it is not working.

Figure 5.16 (a) The preferred type of goggles allowing no light leakage and clearly marked with a guide wavelength. (b) Wrap-around type plastic goggles, note that no wavelengths are indicated.

Figure 5.17 A self-adapted Nikon D70 with the IR filter removed.

Figure 5.18 A low energy E27 bulb fitted into a standard inspection housing, with the metal cage removed.

Figure 5.19 A ring light inspection lamp.

Figure 5.20 (a) A light box being used to create black field illumination. (b) The resultant mark reverse-coloured for comparison purposes. It is interesting to note here that, unusually, the sheet of plastic with the mark on it is hanging, rather than being laid flat. This was because it was not possible to achieve the right angle and distance to illuminate the mark properly when the plastic was laid on a glass-topped table.

Figure 5.21 A Schott inspection lamp fitted with a ring light fibre optic. In this case it is being used to produce dark field illumination on latent finger marks on glass.

Figure 5.22 A Kodak carousel being use to illuminate a vinyl floor.

Chapter 6

Figure 6.1 A burn to the arm photographed using (a) white light (b) cross-polarised light, (c) reflected ultraviolet, (d) induced fluorescence, (e) infrared.

Figure 6.2 A kidney photographed with normal flash and under cross-polarised illumination. Although in this case the surface of the kidney is quite dry, the surface detail is lost under standard flash illumination, whilst under cross-polarised light the surface is clean and clearly defined. If this were a wetter, shinier surface, this effect would have been more evident.

Figure 6.3 The above points in practice. Here five different techniques have been used to photograph a burn injury: (a) white light (b) cross-polarised light (c) reflected ultraviolet (d) induced ultraviolet fluorescence (these images are often left in colour to aid comparison due to the increased colour contrast) (e) infrared. Note: even though a number of different cameras have been used, all the injuries are taken at the same angle and orientation allowing easy comparison.

Figure 6.4 A bite mark to a child's hand (a) with the injury cropped tight in the frame, so its exact location on the body is not obvious. (b) The same injury with some surrounding area showing location. Both ways are acceptable but for different mediums; (a) would work well in a digital only form whereas (b) would be a more acceptable use of the frame for a print.

Figure 6.5 The arrangement of camera to injury. Image courtesy of Ruth Bowen, Cardiff University.

Figure 6.6 Shows the use of one flash (a) Lit from the left, producing harsh shadows and flare on the background. (b) Here the light has been bounced off the ceiling, producing a softer light with almost no shadows. Both images would show an injury to the face but (b), I would argue, is less distracting and more professional looking. This is one of the most common problems I encounter when looking at supplied images from other agencies. In scene photography the use of one flash does not present a major problem, as the distance to target is usually sufficient to ensure even illumination of the target. However, unless careful consideration is given in injury photography, it can produce uneven illumination, harsh highlights or flare that always falls across the injury under interpretation. Photographs taken at f11, at 1/ 125th at 400ISO using an SB-700 set to TTL.

Figure 6.7 A selection of forensic rulers and a colour checker chart.

Figure 6.8 An assault injury to the wrist (a) under normal flash illumination (b) under cross-polarised illumination. Note the increased skin saturation and lack of reflections.

Figure 6.9 Here we can see a coin attached to the corner of the ruler; if you haven't got a coin to hand, then any highly reflective metal object will work.

Figure 6.10 (a) The two polarising filters placed so they are overlapping, then being turned. (b) The filters in the cross-polarised position, using both a glass filter and using a sheet of filter fitted to a plastic flash diffuser. Although it may appear that there is no light passing through, only around two stops are lost in the process.

Figure 6.11 The top of the filter marked with a white dot.

Figure 6.12 A sheet of polarising filter. As stated, the filter must be fitted to the exterior of the plastic filter; also note how the sides of the filter that are angled have been masked to remove unwanted un-polarised light.

Figure 6.13 The camera and flash ready to undertake cross-polarised photography.

Figure 6.14 A correctly cross-polarised ruler. Note that the coin is devoid of any reflection. It is important to remember that, although this is a good indicator, if it is not exactly at 90° during photography, the rest of the photograph could be polarised.

Figure 6.15 The D700 used to record a burn injury. (a) Shows the reference image taken on a D800. (b) Shows the reflected UV taken on the adapted D700. Note that due to the way the sensor works the UV image appears in the red channel. This is another reason why, for evidential purposes, the images should be provided as greyscale.

Figure 6.16 An adapted D700 fitted with a quartz 105 mm macro lens and adapted flash.

Figure 6.17 (a) Shows the adapted Quantum flash heads one fitted with the filter one with the filter removed, this emits between 420 and 460 nm. You can also show the orange Lp510nm camera filter on the left. (b) Shows our adapted Labino head fitted with a Quantum flash, which emits around 350–410 nm. As stated above the reflected UV flash can also be used if you have one.

Figure 6.18 A burn to the forearm (a) under normal electronic flash and (b) under induced UV fluorescence. Converted to greyscale in Adobe Photoshop.

Figure 6.19 An injury caused by a flat metal coat hook (a) under white light (b) under IR. If you look carefully you can see the main shape, which is flat in the middle curving away towards the bottom of the image.

Figure 6.20 Shows an example of all five techniques used on a burn injury. (a) The reference image taken under standard electronic flash (b) cross-polarised image (c) reflected UV (d) induced fluorescence (e) infrared. Clearly the results of each technique will change dependant on the injury type, but this example shows the importance of trying all the techniques.

Figure 6.21 Shows (a) the reference image (b) cross-polarised light (c) induced fluorescence (d) reflected UV (e) reflected UV 24 months after the incident. Although the image in (e) is not as clearly defined as the original RUV image (d), the outline of the shape of the burn is still recognisable. The best results are seen on paler European skin, as there is less interference from melanin within the skin. In African and Asian skin tones we have found using cross-polarised light above can recreate the injury to good effect.

Chapter 7

Figure 7.1 A dust mark on a piece of car cowling, lit obliquely with a scenes of crime torch. Some friction ridge characteristics are clearly visible, but the mark is probably not identifiable.

Figure 7.2 The same mark, this time lit with specular illumination using a ball light, revealing the greasy contact area of the mark.

Figure 7.3 Photographic illustration of fingerprint patterns that shows the main fingerprint pattern types: (a) arch (b) approximating arch (c) tented arch (d) loop (e) nutant loop (f) twinned loop (g) whorl (h) composite (i) lateral pocket (j) accidental.

Figure 7.4 The main fingerprint characteristics: (a) ridge ending; this is where a ridge stops short and flanking ridges converge to take its place; (b) bifurcation; this is where a single ridge divides into two and the flanking ridges diverge to make room for it; (c) short independent ridge; this is a portion of ridge lying between two other ridges, which end in both directions; (d) lake; this is where a ridge diverges into two and then converges again within a short distance; (e) spur; this is a combination of a spur and short independent ridge.

Figure 7.5 First, second and third level details.

Figure 7.6 A shoe mark in blood like contaminate made on paper. (a) shows the first step (b) shows the fourth step. (c) Shows b converted to greyscale to aid the scientist in identification. Note that shoe marks are provided in either colour or greyscale, depending on the contrast between the mark and substrate.

Figure 7.7 (a) A shoe mark in soil (b) an indented shoe mark in insulation foam board (c) shoe mark left in wet varnish.

Figure 7.8 An aluminium powdered lift (a) scanned and (b) photographed with oblique lighting.

Figure 7.9 A blood mark on the label of a bottle. (a) shows the mark lit with oblique lighting (b) shows the same mark lit with specular or coaxial lighting using a ball light.

Figure 7.10 A white, plastic bag stretched over an embroidery hoop.

Figure 7.11 One of the photographers at work.

Figure 7.12 A conventional copy stand set-up. These are good for flat copy work, but they do not allow three-dimensional objects to be illuminated or positioned as required, due to the limited camera position.

Figure 7.13 A variant of Figure 7.12, fitted with balanced 45° lighting.

Figure 7.14 (a) Shows a standard office ring light with the magnifier removed. This can then be positioned around the lens to produce shadowless bright field illumination, or used behind a translucent surface to produce dark field illumination. (b) Shows the Schott light fitted with a standard fibre optic. Note that the display on the front of the Schott light is showing the colour temp of the light. Although generally not important for finger marks, which are traditionally converted to a greyscale, it could be important if used to light an exhibit for reference purposes.

Figure 7.15 A CNA mark illuminated with a ring light at (a) 10 cm from the surface (b) 15 cm from the surface (c) shows (a) after post-production conversion.

Figure 7.16 (a) The mark illuminated using bright field illumination. (b) The same mark using dark field illumination.

Figure 7.17 (a) Shows a mark on tape window mounted and held in a retort stand. (b) Shows the photographed mark after postproduction through Photoshop.

Figure 7.18 (a) The magnetic board (b) the bag roughly positioned (c) the bag just before the magnets are moved to stretch the bag (d) the magnets stretching the bag, removing wrinkles with the mark lit from behind.

Figure 7.19 (a) Selection of the blue channel only removed most of the background writing. (b)The final enhancement once the red and green channels had been removed and the mark had been inverted and adjusted using curves.

Figure 7.20 A faint and poorly lifted aluminium powder mark (a) scanned on a flat bed scanner. Note how the image has degraded, as the tonal range was adjusted allowing the mark to be seen. (b) Shows the same mark, but this time photographed using dark field illumination. Note the increased clarity of the marks on the right hand side in comparison to the scanned version. (c) Shows the lift after post-production conversation.

Figure 7.21 A greasy mark on a double glazed window. (a) shows area directly behind the mark across the street. (b) shows the mark in focus but not aligned properly. (c) shows the mark after being aligned with the brickwork to create dark field illumination. (Note that the mark would normally be reversed coloured before submission to the fingerprint bureau.) (d) shows the mark aligned with the garage door to create bright field illumination.

Figure 7.22 A Kodak projector being used to illuminate a latent dust shoe mark.

Figure 7.23 A dust lift before and after electrostatic lifting (ESL). Note that the ESL version has been reversed for comparison purposes.

Figure 7.24 An untreated latent mark on the side of a tape dispenser. The ball light is generally held so that it is on the same axis as the lens. In effect you are looking at the reflection of the light. Any contaminate, for example, the greasy finger mark, will not reflect and will appear black against a white background.

Figure 7.25 An untreated latent mark on an electric plug, (a) General shot, (b) Oblique lighting (c) Specular lighting. Note in the specular version 3rd level detail such as the pores, are clearly visible. Note that when powdered, no usable marks were retrieved.

Figure 7.26 A latent mark on a television screen (a) Using a ball light. Note how the mark is pale and lacks contrast out due to the surface of the screen. (b) Illuminated with a Schott fibre optic, note that in many circumstances these marks clog when powdered or do not powder at all as they are ‘baked onto’ the glass.

Figure 7.27 My home made coaxial device, which can be screwed onto the front of the lens. Using a sheet of glass rather than a front-silvered mirror loses around 50% of the light; however, it can still produce very acceptable results.

Figure 7.28 A latent mark on a phone battery illuminated by light reflected onto a sheet of white A4 paper. Note how the mark disappears on the edge of the battery where the surface is not smooth, but textured.

Figure 7.29 A latent mark on a light switch using (a) oblique lighting (b) using a ball light.

Figure 7.30 The author using a ball light to examine a door and door frame.

Figure 7.31 A CNA mark on a plastic bag being illuminated by a ring light bounced off a white card. (Note that when the ring light was used directly behind the bag, it failed to reveal the mark correctly.)

Figure 7.32 A DFO mark on an envelope exposed at 1/8th at f8 400ISO.

Figure 7.33 A nin mark on an orange envelope.

Figure 7.34 (a) shows VMD mark on a plastic bag (b) shows conversion to inverted greyscale.

Figure 7.35 A typical CNA mark on a white plastic bag, in this case illuminated from behind using a ring light.

Figure 7.36 (a) a mark on a plastic bag treated with BY40 illuminated at 445 nm with the laser exposure of 1/4 s at f8 400ISO. (b) Shows the adjusted inverted greyscale conversion.

Figure 7.37 A BY40 mark (a) bag treated with CNA and BY40 (b) stretched using an embroidery hoop, then photographed as a specular mark using a ball light.

Figure 7.38 (a) A lid of a can treated with green glow fluorescent powder (b) after excitation with UV exposed at 1/15th s at f8 600 ISO.

Figure 7.39 (a) White light control photograph. (b) Naturally induced fluorescence using an excitation wavelength of 532 nm and a 549 nm long pass viewing filter.

Figure 7.40 The use of two ball lights to illuminate a latent mark on a thin strip of metal. Note that the distance of the two lamps from the mark is different to optimise the contrast in each side of the mark.

Figure 7.41 A latent mark, on a typical surface often found at scenes. (Area enclosed by red box.)

Figure 7.42 The areas above photographed using the open exposure technique. Note that this took a number of attempts to get right, as the dimples in the bottles surface became very pronounced and affected the mark if the light was held too close.

Figure 7.43 A ball light with and without a black paper shield.

Figure 7.44 A DFO hand mark on an A3 envelope.

Figure 7.45 A fluorescent mark photographed (a) with the label in for the full exposure (b) removed after 2 s. By overexposing the label in photo (a) not only has the flare interfered with the main mark, but the mark to the right has also has very little information when photograph (a) is compared to photograph (b).

Figure 7.46 A latent fluorescent mark under 532 nm after post-production. (a) With the label left for the full exposure (b) with the label covered after 2 s. Again the mark in photograph (a) is less defined due to the flare caused by the overexposing label.

Figure 7.47 A pathfinder ESL being used.

Figure 7.48 A mark in blood (a) under white light (note the background interference from the greasy surface deposits). (b) Under UVA – the use of UVA is an easy quick method for searching for blood on laminate and wooden floorings.

Figure 7.49 A gelatine lift illuminated from (a) a low oblique angle of approximately 2° (b) an oblique angle of approximately 45° (c) as a specular mark. Note how each lighting technique reveals a different part of the shoe mark. It is therefore very important that they are examined under controlled, darkened lighting conditions. So if this is not available at the scene, they should be packaged and re-examined within the laboratory.

Figure 7.50 A mark in snow illuminated in three different ways. (a) Ambient illumination. Notice how the definition of the mark is soft. (b) Flash illumination pointed straight down, again the resultant image appears flat with few 3D characteristics. (c) Flash at 45° from right hand side. This was exposed at 1/125 at f19 with the ambient daylight being shielded by my coat. Note the fine lines on the instep part of the shoe, which are missing from (a) and (b).

Figure 7.51 A shoe mark in blood on a dark coloured t-shirt. Note that the image at ¼ s is about the right exposure to reveal all of the shoe mark. Although it is possible to adjust the image to some extent within imaging software at the later stage, it is always better to get it right in camera, particularly if it is not you who is undertaking the post-production.

Figure 7.52 A mark in fire extinguisher powder taken under (a) flash illumination and (b) cross-polarised flash. To undertake this technique see Chapter 6 on using cross-polarised light.

Figure 7.53 The left-hand side of the image shows a mark photographed conventionally, then converted to a greyscale and then as a red channel. On the right is the same mark photographed with a red filter, then as a greyscale, then after being mixed in channel mixer.

Figure 7.54 Shows boom arm attached to a tripod allowing the camera to be positioned at 90 degree to the mark. Photographic illustration.

Figure 7.55 Blood marks treated with acid yellow 7. (a) Photographed with specular illumination prior to treatment. (b) Photographed under oblique illumination. (c) Photographed as a fluorescence mark using a 445 nm laser and 550 nm band pass camera filter. (d) Photographed using the 445 nm laser and no camera filter.

Figure 7.56 A blood mark treated with acid violet. (a) Photographed as a specular mark prior to treatment. (b) Photographed with oblique lighting. (c) Photographed using a 445 nm laser and 550 nm band pass filter. (d) Photographed using a 455 nm laser and no camera filter.

Figure 7.57 Blood marks (a) Photographed with oblique white light. (b) Photographed as a specular mark. (c) Photographed after treatment with Amido Black.

Figure 7.58 (a) Shows the CD in position held in a retort stand, with the squeezy bottle held just under the mark. (b) Shows a correctly huffed mark and the final reversed colour image after post production.

Figure 7.59 (a) Shows our dead set training hand. (b) Shows the use of the ring light (desk inspection lamp) to individually light each finger.

Figure 7.60 A dead set cast illuminated with a ring light (a) as received after sterilisation and washing (b) after the application of graphite powder.

Chapter 8

Figure 8.1 A t-shirt photographed under (a) white light illumination; (b) under the blue laser at 445 nm.

Figure 8.2 Various dilutions of semen applied to a yellow towel photographed two years after being applied. (a) Under white light illumination. (b) Under laser illumination at 445 nm.

Figure 8.3 A possible sexual assault scene (a) under white light illumination; (b) under 445 nm with areas of body fluid indicated with yellow arrows. Note the hand shaped mark at six o'clock, indicating four fingers and a thumb. This could be important in the context of the case. Also note the 6–10 small red fibres, which can also be clearly seen fluorescing on the carpet. These may have been shed from the attackers garment and so may be important if fibre analysis is being considered at a later stage.

Figure 8.4 A section of wall under (a) white light illumination; (b) under the laser at 532 nm. It is important to note that the writing did not fluoresce under any other wavelength, due to the autofluorescent nature of the paint used.

Figure 8.5 An example of erased ink on skin. (a) We can see the reference shot of my hand, 48 hours after the application of blue ink on the palm. Note that normal everyday washing has removed all visible traces of the ink. (b) Shows the same area under the green line 532-nm laser.

Figure 8.6 A van door with a sign on it. (a) Under white light illumination. (b) Again under white light illumination but with the signage removed. (c) The same area under UV light. Although you may think that you would only see a black square where the girl's face was, you can actually see the difference of where the stencil's colour has let through the light at different rates. Also note the returning ‘n’ in ‘ordinary’.

Figure 8.7 A white van illuminated using UV, note that not only is the removed sign writing livery visible, but also that the side sliding door has at some stage been replaced. This technique would equally show up replaced mirrors, bumpers and bodywork repairs.

Figure 8.8 Blood on red metal tape dispenser. (a) Photographed using white light. (b) Photographed using UV. (c) Extraction of blue channel and green channels only, then converted to greyscale using Adobe Photoshop.

Figure 8.9 (a) An area of wall under white light. (b) The same area under UV illumination. The darker handprint in the middle is my original blood mark and the fluorescent surrounding region shows the area that I have cleaned with bleach and water.

Figure 8.10 A bloodstained shower cubical (a) under white light illumination; (b) after the application of luminol, exposed for f8 for 30 s at 400ISO; (c) a Photoshop blended layer image of photographs (a) and (b) together.

Figure 8.11 A carpet tile. (a) control image; (b) luminol image; (c) overlay of both images together.

Figure 8.12 The visual damage caused by a self loaded 9 mm round, fired at a distance of around 20 cm. (a) Shows the reference photograph under white light. (b) Shows the same area shot under IR, here the particles of burnt and unburnt propellant are clearly visible. Photography was carried out using an adapted Nikon D70 fitted with a 730-nm long pass filter. The illumination used was the Bowens studio flash modeling light, fitted with a soft box, exposure f11 at 1/30th at 400 ISO.

Figure 8.13 (a) Reference image of a pair of underpants exposed at f8, ¼ second 200 ISO. (b) Shows the above overexposed by three stops, at f8 2 s 200 ISO with the blue channel only selected and enhanced using highlight shadow command in Adobe CS5. Note how the shoe mark is now clearly visible but lacks detail within the minutia of the mark. (c) Shows the above using IR, illuminated with the Bowens studio flash set to modelling light and fitted with a soft box. Exposure was with an adapted Nikon D70, using a 700-nm long pass filter fitted to the lens and exposed at f5.6 at 1/20th second at 600 ISO. Note how the detail in the toe area is now clear and could be used for identification.

Figure 8.14 The effect of IR on an arm. Exposure was with an adapted Nikon D70, using a 700 nm long pass filter fitted to the lens and illuminated with a Redhead studio light. Exposed at f8 for 1/20th s at 400 ISO.

Figure 8.15 An example of how a garment can change colour depending on its reflectivity to IR light. (a) Shows a black coat under controlled studio lighting. (b) Shows the same coat under infrared photographed using a 700–900 band pass filter.

Figure 8.16 Shows a motorcycle coat under (a) studio flash (b) under IR illumination. Note how, under the IR, the distinctive bright orange reflective strip has disappeared, making it look like a different coat. Bowens studio flash modeling lights, fitted with a soft box, provided the IR illumination. Photographed with the adapted Nikon D70 fitted with an 840-nm long band pass filter and the exposure was f8 at 1/30th s at 400 ISO.

Figure 8.17 Shows a heat-damage document under (a) flash illumination using a Nikon D800; (b) under daylight illumination using an unfiltered IR adapted Nikon D70. Note that although some of the telephone number is visible in ‘A’, the six end digits are illegible.

Figure 8.18 An example of over-painting, in the control shot (a) nothing is visible in, but in (b) we can see the shoulder has been repainted. Under normal circumstances IR or even x-rays might be used, but unusually this was found using the Crimescope at around 460 nm.

Figure 8.19 The area of interest on the manuscript. (a) The reference image, under white light. (b) The backlit image photographed on a light box. (c) A UV backlit image. (d) Shows (c) converted to a greyscale and reverse coloured. Image courtesy of the Metropolitan Police, first published in Dillon,

Michaelangelo and the English Martyrs

, Ashgate Press, 2012.

Chapter 9

Figure 9.1 An original adapted 5 × 4 camera with mechanical slit.

Figure 9.2 Here we can see the camera and turntable attached to the optical bench. As with all fingerprint photography, lighting is critical and here we see the mark being backlit through the glass.

Figure 9.3 A 5-mm diameter .22 brass cartridge case. Normally these would not be photographed for finger marks, due to the lack of attainable and usable marks. Here, however, we can see that with careful lighting, a latent fingerprint is visible. Note that the bottom part of the mark is covered with the teeth of the vice holding the exhibit in place. The vice is critical when working at macro levels and close working distances to ensure the exhibit is exactly centered. If this were a real case, the image would have been retaken. This time by turning the cartridge case upside down and placing it onto a small rod, which has a fractionally smaller diameter than the cartridge case, so that it snugly fits inside it. It is also approximately twice the length of the cartridge case, and this rod is then held secure in the vice. This technique was created due to the issues raised by this very image and now we have a selection of rods for a number of calibers. As an aside, longer rods can be used inside gun barrels, to ensure that they also rotate around their central point.

Figure 9.4 The 16 mm, 34 mm and 52 mm extension tubes.

Figure 9.5 A 100-mm Rodenstock lens fitted to its own extension tube mount, attached to a 6 mm and 52 mm extension tube. The block on the right hand side attached by the Ethernet cable is the scanner back.

Figure 9.6 A blue mug that has been lit with the ball light, you can see that the reflection is limited both in width and in height and so is of no practical use in illuminating the mark.

Figure 9.7 This shows the result after post-production enhancement and conversion to a greyscale image.

Figure 9.8 A finger mark on a correction fluid bottle.

Figure 9.9 A Mont Blanc pen: colour version.

Figure 9.10 A Mont Blanc pen: the post-production image.

Figure 9.11 Here we see the view looking towards the exhibit from behind the camera. Note the simple insertion of a black pen held in a retort stand allows the light to reach the mark but provides a dark field for the photograph and stops the logo being exposed again once it rotates to the back of the glass.

Figure 9.12 The table, lighting and electronically controlled arm allowing a full 360-degree image of the object to be undertaken.

Figure 9.13 A fully interactive 360 example.

Figure 9.14 Here we can see the camera fixed onto a copy set-up with the illumination being provided by Crimescope CS16.

Figure 9.15 Showing an area of multiple ink lines.

Figure 9.16 Showing Figure 9.15 after extraction.

Figure 9.17 Here we can see the original control of the mark.

Figure 9.18 Here is the unmixed colour cube with each separate colour of the £10 note, now represented in one of 10 new colours.

Figure 9.19 Here we can see the final extraction and conversion to a 4.5 meg greyscale image. This is saved as a tiff file and can printed or imported into any other application, such as Photoshop, if required.

Figure 9.20 A nin mark on a £20 note, note how the nin stains all the background due to the constant handling.

Figure 9.21 Here we can see the colour signal of the £20 note has been removed. Note that some interference is still visible, but compared to the original mark it has been greatly enhanced.

Figure 9.22 In this image the muzzle flash provides the main exposure, with fill in flash providing illumination to the arm and hand. The main exposure was of several seconds, so it is clear that little or no gas or flames escape from the chamber area. As an aside, when the muzzle was loaded with a ball bearing and fired, the ball bearing travelled through one and a half telephone directories.

Figure 9.23 The front of the Shutter-beam device. The left side panel (out of sight) contains the power switch mains power socket, 2.5 phono socket (camera out) and PC jack for strobe out. The right panel (out of sight) contains the cameral pulse duration settings and the beam settings for Make or break, Steady or pulsed, and beam on or off. The rear panel contains the IR beam generator and receiver and the microphone.

Figure 9.24 The ADDjust box, showing the increment changes that can be achieved.