Institute of Criminalistics Prague

The Czech republic

Practical use of digital photographyPractical use of digital photography WoWorking procedurerking procedure

Petr BendlPetr BendlJaroslav TichýJaroslav Tichý

IntroductionIntroduction The aim is to determine such working The aim is to determine such working

procedure,procedure, which enables that the following which enables that the following criteria are met:criteria are met:

dduring photographic documentation by uring photographic documentation by a a digital camera it is easy to prove image digital camera it is easy to prove image credibility,credibility,

ccredibility shall be easy to prove also during redibility shall be easy to prove also during subsequent work with digital image data in subsequent work with digital image data in fufurrther processing and storing,ther processing and storing,

tthe possibility of loss, damage or destruction he possibility of loss, damage or destruction of the data practically excluded.of the data practically excluded.

Photography in the shape of digital image data is Photography in the shape of digital image data is easily vulnerable and incorrect treatment can easily vulnerable and incorrect treatment can lead to their loss, damage or destruction.lead to their loss, damage or destruction.

Competence of workers makCompetence of workers makiing ng photographic documentation by a digital photographic documentation by a digital cameracamera

Education and training in the field of internal Education and training in the field of internal regulations setting down the exact procedure regulations setting down the exact procedure of photographic documentation.of photographic documentation.

Practical ability to carry out individual working Practical ability to carry out individual working procedures used for photographic procedures used for photographic documdocumeentation determined by these internal ntation determined by these internal regulations.regulations.

Proper understanding of individual functions Proper understanding of individual functions and manipulation with cameras and computer and manipulation with cameras and computer technology, through which storing and technology, through which storing and adjustment of digital image data are made.adjustment of digital image data are made.

Working procedure Working procedure

desdesccriptionription Work with digital photographic Work with digital photographic

technology when taking digital picturestechnology when taking digital pictures A digital camera with accessories must always A digital camera with accessories must always

be stored independently in a camera bag be stored independently in a camera bag suited for that purpose. In no case can it be suited for that purpose. In no case can it be stored together with fingerprinting equipment stored together with fingerprinting equipment (fingerprint powder, brushes etc.) and ot(fingerprint powder, brushes etc.) and othher er chemical substances and agents used for chemical substances and agents used for recovery of evidence at crime scene.recovery of evidence at crime scene.

At workplace before going to At workplace before going to the scenethe scene::

ccheck of functionality of a camera and its heck of functionality of a camera and its accessoriesaccessories,,

ccheck of battery, life remaining (a camera set heck of battery, life remaining (a camera set must always spare functional batteries)must always spare functional batteries),,

ccheck of preset functions of the camera and heck of preset functions of the camera and accessories (mostly in cases where devices are accessories (mostly in cases where devices are shared by more workers)shared by more workers),,

ccheck of completeness of the camera setheck of completeness of the camera set,, ccheck of memory card status (it is advisable heck of memory card status (it is advisable

that the camera set contains a spare memory that the camera set contains a spare memory card).card).

At the scene or before taking At the scene or before taking photographs:photographs:

sset the quality of images, if necessary – with forensic photo-et the quality of images, if necessary – with forensic photo-documentation of crime scene and with taking identification documentation of crime scene and with taking identification photos (three-part photographotos (three-part photograpphs and pictures of special hs and pictures of special marks and tattoos the size of the image must be at least 5 marks and tattoos the size of the image must be at least 5 million pixels),million pixels),

bbased on light conditions set the needed sensitivity in ISO,ased on light conditions set the needed sensitivity in ISO, bbased onased on the light source used, make chromatic adaptation the light source used, make chromatic adaptation

through white balance,through white balance, mmake choice and set suitable ake choice and set suitable exexposure prograposure programmme,me, ccheck the exposure and correct parameters of a test image, heck the exposure and correct parameters of a test image,

possible re-adjustment of exposure measurement or possible re-adjustment of exposure measurement or correction of exposure,correction of exposure,

ccheck correct focus,heck correct focus, tthe photographic documentation itself is carried out in he photographic documentation itself is carried out in

compliance with internal regulations applicable for classic compliance with internal regulations applicable for classic photographic documentation.photographic documentation.

Archiving and storing of digital Archiving and storing of digital image image data filesdata files

The person who made the files is always responsible for The person who made the files is always responsible for their archiving (storing).their archiving (storing).

Upon return to the department, the original file of digital Upon return to the department, the original file of digital image data is immediately transferred from the memory image data is immediately transferred from the memory card or internal memory of the camera to the PC card or internal memory of the camera to the PC (serv(serveer), which is used solely for the purposes of r), which is used solely for the purposes of archiving digital image files in a directory created archiving digital image files in a directory created before, so that it is possible to retrieve them easily before, so that it is possible to retrieve them easily anytime.anytime.

If the relevant department does not have a PC (server) If the relevant department does not have a PC (server) for archiving digital image data, then the original file of for archiving digital image data, then the original file of digital image data is immediately transfedigital image data is immediately transferrred from the red from the memory card or internal memory of the camera to the memory card or internal memory of the camera to the PC (workstation) in directory created beforPC (workstation) in directory created beforeehand, so hand, so that the data can be easily retrieved anytime.that the data can be easily retrieved anytime.

Recommended labeling of the directory (always without Recommended labeling of the directory (always without ddiiacritics!):acritics!):orig-2004-KUP-AK-0357-TI-hen theftorig-2004-KUP-AK-0357-TI-hen theft(original digital image file-year-department symbol-record (original digital image file-year-department symbol-record symbol-serisymbol-seriaal number-author's sign-note)l number-author's sign-note)

Check of their flawless transfer is performed.Check of their flawless transfer is performed. After the check of transfer the image files are deleted from After the check of transfer the image files are deleted from

the memory card or internal memory of the camera.the memory card or internal memory of the camera. Original digital image file is backed up on a CD, DVD or Original digital image file is backed up on a CD, DVD or

another medium, on which the data cannot be deleted, another medium, on which the data cannot be deleted, overwritten or additionally adjusted.overwritten or additionally adjusted.

The backup is performed twice on physically separated The backup is performed twice on physically separated media (two CDs or DVDs).media (two CDs or DVDs).

One such medium will serve as a working backup, the One such medium will serve as a working backup, the second one as an archive backup. In case the working second one as an archive backup. In case the working backup is impossible to read (mechanical damage etc.), a backup is impossible to read (mechanical damage etc.), a new working backup is made from the archive backup. The new working backup is made from the archive backup. The original archive backup will than be used as a working one original archive backup will than be used as a working one and the newly created one will be used for archiving. and the newly created one will be used for archiving. Archive backup must not be used for any other purpose.Archive backup must not be used for any other purpose.

Archive backup is always stored at the department where Archive backup is always stored at the department where the photographic documentation was made.the photographic documentation was made.

Working with image dataWorking with image data

It is prohibited to tamper with the digital It is prohibited to tamper with the digital image data in anyway.image data in anyway.

It is prohibited to remove any, even poor-It is prohibited to remove any, even poor-quality images (smudged, with wrong quality images (smudged, with wrong exposure etc.) from the original file.exposure etc.) from the original file.

A properly labelled A properly labelled copycopy is created from the is created from the original file of digital image data.original file of digital image data.

Recommended labelling: Copy-2004-KUP-AK-0357-TI-hen theft

(a digital image file copy-year-department symbol-record symbol-serial number-author's sign-note).

Working with a copy:Working with a copy:

It is It is prohibprohibiitedted to use any methods, which to use any methods, which lead to alteration of the content of the original lead to alteration of the content of the original photographic image or to its optical photographic image or to its optical deformation (local color adjustments, deformation (local color adjustments, manipulating with depicted objects and texts manipulating with depicted objects and texts and other montages).and other montages).

Adjustments permitted in Adjustments permitted in a copya copy of the digital of the digital image file:image file:- choice and new order of images,- removal of poor-quality images,- supplementing individual images with description,- adjust a selected part, brightness, contrast, colors, sharpen,- adjust its size.

Making photographs from digital Making photographs from digital image dataimage data

PhotogPhotogrraapphs from digital image file are processed in hs from digital image file are processed in a digital minilab or an analogue minilab with digital a digital minilab or an analogue minilab with digital exposure unit.exposure unit.

Minilabs are deployed centrally in individual regional Minilabs are deployed centrally in individual regional administrations and some departments of the Police administrations and some departments of the Police Presidium.Presidium.

Digital image files are sent for processing to the Digital image files are sent for processing to the minilab:minilab:- via offic- via officiial mail on data media (CD, DVD, ZIP etc.),al mail on data media (CD, DVD, ZIP etc.),- electronically via computer networks (internal police - electronically via computer networks (internal police network etc.).network etc.).

Photographs from digital image files can Photographs from digital image files can exceptionallyexceptionally be processed at the respective department or body, if be processed at the respective department or body, if this is required by the nature of the service (e.g. this is required by the nature of the service (e.g. operational activity, where there impends a danger in operational activity, where there impends a danger in delay).delay).

Thank you for your attention.Thank you for your attention.