IFI designs sample standard operating procedures for the use of digital photography in law enforcement

58 Law Enforcement Technology • June 2000

In response to an article on digitalimaging that appeared in theFebruary 2000 issue of LET manyreaders asked for sample standard

operating procedures (SOPs) in regardto digital photography. To meet thedemand, the Institute for ForensicImaging (IFI) wrote the procedures onPages 59 and 60. One SOP is designedfor a patrol officer, who is providedwith a digital camera and asked to useit to document certain situations. Thesecond SOP is for the photo specialist,who will process the images officersturn in.

These SOPs are merely samplesand it is strongly recommended thateach agency customize them to itsspecific circumstances. To help yourdepartment develop specific SOPs,however, it is useful to study the fea-tures built into the sample SOPs.

The digital cameraThe sample SOPs (SSOPs) first

specify the camera and CDs to beused. These are fundamental specifica-tions. The camera should be one withat least 1 million pixels. It should notbe a camera that resorts to high com-

pression ratios to put several imageson a floppy disk. Experience hasshown that anything less than 1 megapixel will give results of ques-tionable quality. There are several rea-sonably priced, high-quality camerasthat exceed this minimum.

The CDs specified in the SSOPsare write-once-read-many times(WORM) disks that have embeddedserial numbers. This means that oncethe image information is recorded onone of these CDs and its index is pre-served elsewhere, there is a uniquelyidentifiable and virtually incorruptible

Creating the digital image SOPBy Herb Blitzer

Flash card With image

files

Zip drive w/case file

* These files are neveropened on a devicethat supports imageediting.

Diagram courtesy of the Institutefor Forensic Imaging.

WORM,Serial # CDw/case files

Raw *Images

Processed Images

Computer hard drivew/case file

Raw *Images

Processed Images

Camera*image files Raw *

ImagesProcessed

Images

Creating the digital image SOP

1

2

3 45

The diagram shows the process describedin the sample Photo Specialist SOP foundon Page 60. In Steps 1, 2 and 3, the photospecialist duplicates image files from theflash card without opening them. In Step 4,after first processing the images for print-ing, the photo specialist saves theprocessed image folder to the secure zipdrive. Then in Step 5, when the two securezip drives are full, the photo specialist dupli-cates the contents of the drives, unopened,to a serial-numbered WORM CD.

addition, the user wants to store asmany images as possible in the cam-era. Cameras with floppy disks have asetting that allows the user to store 20to 24 images on a single floppy disk.But doing this requires a compressionratio of about 65:1. At this level, sig-nificant amounts of information willbe lost in the storage process.

And to make matters worse, theprocess by which information is lost isone that inserts artifacts into photos.For example, the large compressionratios actually can exaggerate woundsby placing a dark ring just inside theperiphery of the dark red portion ofthe wound and creating a light ringjust outside it. In essence, the edge of

of information. Flash cards are rugged,easy to use and reusable. Floppy disks,by comparison, hold only 1.44 MB ofinformation, are less rugged, but alsoare easy to use and reusable.

The capacity difference betweenflash cards and floppy disks is moreimportant than it might seem becausea 5-inch by 7-inch print should be sup-ported by a 4.5 MB image file. In

record of the images. The CD serves apurpose similar to that served by nega-tives in traditional photography.

Some of the digital cameras in theprice and complexity range specifiedfor this application compress imagefiles using the JPEG algorithm prior tostoring them on the camera’s remov-able storage medium. JPEG is anapproach that is both variable and“lossy,” as it permanently discardssome of the information. Some ofthese cameras offer sett ings thatenable the user to adjust the level ofcompression.

In many other cameras, however,the storage medium is a “flash card”that is capable of holding 8 to 96 MB

June 2000 • Law Enforcement Technology 59

Cameras with largecompression ratiosshould be avoided.

P a t rol Officer SOP

Function covered: Photography of incidents by a patrol officer.

P u r p o s e : When a patrol officer is called to a scene or comes acrossan apparent incident, this procedure should guide the process of doc-umenting the situation with a digital camera.

Equipment and materials: Each officer is issued a Kodak DCS215 digital camera for use in such situations. There also is a kit thatincludes a 6-inch evidence ruler with white, gray and black patches, abattery charger, three sets of nickel-metal-hydride batteries, two 16 MBflash cards, a line-connect power source, and a download cable.Cardboard evidence envelopes are available at each district office, andit is expected that each officer will keep a few of these on hand whileon patrol.

P r o c e d u r e s : When covering incidents such as burglaries, domesticbattery, non-injury or minor injury accidents, the officer is expected todetermine if the investigation will be aided by photo documentation.When in doubt, take pictures, and lots of them.

Camera settings: The camera should be set to “automatic” forexposure, flash and focus. The viewer should be in the “on” position.The storage control should be set to “best quality.” The viewer can beused to look at images, but the images should not be opened up in acomputer or any other device that allows image editing.

At the scene: Photos should include general scene shots to showwhat the situation looked like at the time. If there are broken windows,furniture, decorations, etc., that are indicators of violent action, careshould be taken to show these items. If there are injuries of any sort,close-up (about 10 to 12 inches away) photos of these should betaken with an evidence ruler in the picture. When taking close-up shots,the officer should cover part of the flash window with a finger to subduethe exposure. In addition to close-ups, broader shots of any injuredpeople should be taken, including full-length shots. Head-and-shoul-ders photos of all apparent victims at a scene also should be taken. Ifthere are weapons, alcohol containers or drug-related paraphernalia atthe scene, these items should be photographed too. When taking pho-tos of paraphernalia, wounds or other items where it may be importantlater to know the size of the subject of the photo, two pictures shouldbe taken: one of the item in its original condition and another with anevidence ruler laying close to the subject. If more than 10 shots aretaken, the officer should keep a written record of what pictures were

taken and kept. The officer will need to be prepared to describe thescene and use the photos to illustrate the verbal testimony. Any photosthat are photographically faulty should be discarded at the scene.Photographically faulty images include those with problems from beingout of focus, a flash failure, a blocked lens, inadvertently pushing theexposure button, blurring due to subject or camera movement, etc.

After the on-scene photography: After completing on-sceneduties, the officer should place the flash card(s) used at the scene in acardboard evidence envelope, fill out the case identification informationon the envelope label, and seal the envelope. The sealed envelopeshould be turned in to a photo specialist at the district office, in person.The photo specialist will log case information, the officer, and time anddate of the transfer on the envelope. Both the officer and the photospecialist will sign that the envelope was sealed at the time of transfer.The photo specialist will then follow the crime scene photo processingprocedure to prepare the visible images and archive the records.

Prior to investigations: The officer will keep one set of batteriescharging while on duty, and swap the duty batteries with those in thecharger before going on call the next time. An additional set of chargedbatteries should be carried when on duty, in case power in excess ofthat deliverable by one set of batteries is required. Prior to leaving, theofficer will check to see that the batteries are fully charged to ensure thebatteries in the camera are always ready for use during a shift. Whenworking with the camera, the power-line connector should be used ifconvenient.

C a l i b r a t i o n : While no calibration is needed, the officer is expectedto check the camera on a regular basis and make sure that it is func-tioning normally. If there are any indications of a malfunction, the unitshould be swapped with another by contacting the photo specialist.

L i m i t a t i o n s : Digital cameras are issued to patrol officers primarilyfor use at scenes where photos will help the investigation and possibleprosecution, and an evidence technician probably will not be called tothe scene. If it is used at major crime scenes, it will serve as a backupto the work done by the evidence technician.

S a f e t y : There are no safety issues beyond normal precautions usedwhen operating electrical devices. Batteries should not be heated, andif they get hot while in use or charging, they should be removed fromthe device. Batteries should be turned in to the photo specialist whenno longer functional and exchanged for new ones. They should not bediscarded in any other way except in an emergency.

as to whether the incident was a fightor a battery. And if there is the appear-ance of drugs and/or alcohol use, shotssupporting this can be useful.

Prosecutors also like having close-up shots of wounds with a measuringinstrument in the photo. The SSOPspecifies using an evidence ruler withpatches of white, gray and black on it,which can be a big help in color-balancing the photos later.

line is to avoid the floppy disk cam-eras and this is built into the SSOP.

Image compositionThe next series of points in the

sample Patrol Officer SOP deal withphoto composition. Prosecutors havemade it clear that they would like tohave shots of the setting, overall shotsof the victim(s), and the alleged perpe-trator, especially if there is a question

the wound is exaggerated, making itappear worse than it really is. Theprocess also alters colors, introducingblues and purples that may appear tobe bruises or other wounds.

For these reasons, large compres-sion ratios should be avoided. If adepartment selects a camera with aflash card storage device of just 8 to16 MB, instead of a floppy disk, theeffect is greatly reduced. The bottom

60 Law Enforcement Technology • June 2000

Photo Specialist SOPFunction covered: Processing of images submitted by a patrolofficer by the photo specialist.

P u r p o s e : Patrol officers are instructed to take digital photos undercertain circumstances and to bring the images to the photo specialist onflash cards. This procedure covers the processing of those images.

Equipment and materials: A photo department image process-ing station, complete with peripherals and software, serial-numbered,write-once-read-many times (WORM) compact disks (CDs), nickel-metal-hydride batteries, 16 MB flash cards, zip cartridges, photo-qualityinkjet printer paper, ink cartridges, cardboard evidence envelopes withappropriate labels, and an evidence transfer log book.

P r o c e d u r e s : Each officer is instructed to bring in the flash card, withimages from every incident investigated and documented with their digi-tal camera. The flash card should be sealed in a cardboard evidenceenvelope with a completed case information label on the outside. Theofficer bringing in the envelope, and the photo specialist receiving theenvelope should enter the case information in the transfer log book, indi-cating the case descriptor numbers, and the date and time of the trans-fer. The envelope should be opened and the number of disks in theenvelope entered into the log. Both parties should then sign the entry.The photo specialist gives the officer a new flash card(s) and new enve-lope(s). If new batteries also are required, the old ones should beswapped for new, but initially charged, batteries. The disk(s) in the enve-lope should be stored in the locked holding box until it is time to processthe images. Then the photo specialist should duplicate image files fromthe flash card without opening them. After processing the images forprinting, the photo specialist should save the processed image folder tothe secure zip drive. When two secure zip drives are full, duplicate theunopened contents of the drives to a serial-numbered, WORM CD.(See graphic on Page 58.)When it is time to process the images, the photo specialist shouldremove the disks from the holding box and insert the card into the com-puter. Using the appropriate file management tools, two case foldersshould be created and labeled with the case number. One of these fold-ers will be on the computer’s hard drive and another will be on a password-protected zip cartridge. Then two folders should be createdand inserted into each case folder — one labeled, “Raw Images” andthe other labeled, “Processed Images.” At this point, the right-click copytool should be used to duplicate the contents of the flash card into bothof the “Raw Images” folders. These folders should not be opened untilafter the images have been permanently duplicated later. The contentsthen should be duplicated a second time but placed in the “ProcessedImages” folder on the computer’s hard drive. At this point some of thephotos in the “Processed Images” folder can be opened to check thatthe transfers did occur. If all is OK, the zip cartridge should be removedfrom the computer and secured. Once this is done, the “PrimaryImages” on the flash card should be erased using a disk-reformattingtool. This disk now is ready to be reused. If there are multiple disks in thecase, this series of steps should be repeated until all of the images havebeen duplicated to the appropriate folders on both drives. The imagesstored in the “Raw Images” folder are now known as the “PrimaryImages.”

The images in the “Processed Images” folder should be opened andexamined. All those needing adjustments for color balance, brightnessor contrast should be adjusted using the software tools named. If theimage needs curve-shape adjustment, this should be applied as well.No further adjustments should be made. The images then should beprinted — one copy of each on photo-quality paper and another copyon plain bond paper. The photo-quality image should be viewed by thephotographer at a convenient time and then sent to the prosecutor in aninternal transfer envelope with appropriate seal and case information.The plain paper copy should be filed in the secure photo office file.Images should be printed six images to an 8x11 page. (If the prosecutorwants additional images in other sizes, they will request that afterward.) As soon as the images are printed, the “Processed Image” files shouldbe duplicated onto the password-protected zip drive, and the cartridgeplaced in the locked holding box. Any unusual information regarding theimages or their processing should be noted in a text file kept in the casefolder. Likewise the information found on the cardboard envelope labelshould be entered into a text file and inserted in the case folder. Finally,the date and time of the processing and the name of the person pro-cessing the images should be placed in a text file and stored in the casefolder. When two password-protected zip drives are filled, the contents shouldbe transferred to a CD. To do this, the contents of the two drives areduplicated to a folder and the contents of the folder are then duplicatedto a CD. The cases that have been recorded on the CD should be listedalong with the CD serial number. This record is stored in the securephoto lab file. An entry also is made into the logbook to indicate whichCD (by serial number) holds the contents of the disks that were originallybrought in by the photographer. The images in the “Raw Images” folderon the CD now are known as the “Original Images.” The operator shouldnow open a few of the images on the CD to ensure that the duplicationsoccurred and the files are readable. It is at this point that the “RawImages” folders as recorded on the CD can be opened and the imagesinside can be viewed. (The “Raw Images” folder on the zip drive is neveropened unless there is an emergency.) Once it is ascertained that theimages on the CD are in fact there and readable, the zip drive should bereformatted to make it available for reuse. The images in the “RawImages” folders are “Original Images,” and all of the “Primary Images“have been erased.

C a l i b r a t i o n : The image processing system should be checked byits diagnostic system every working day and the results filed in thesecure photo laboratory office file.

L i m i t a t i o n s : The patrol officer digital cameras are issued primarily foruse at scenes where photos will help the investigation and possiblyprosecution, and an evidence technician probably will not be called tothe scene. If it is used at major crime scenes, the images will backup thework done by the evidence technician.

S a f e t y : There are no safety issues beyond the normal precautionsused when operating electrical devices. Batteries should not be heated,and if they get hot while in use or charging, they should be removedfrom the device. Batteries should be turned over to the district wastedisposal officer when no longer viable. They should not be discarded inany other way except in an emergency.

Creating the digital image SOP

March 1999 • Law Enforcement Technology 61

The SSOPs detail that it is OK todiscard images that are clearly of novalue because of photographic tech-nique or errors. Discarding poor pho-tos avoids wasting disk space and doesnot weaken the case. However, offi-cers should be sure to tell the prosecu-tor trying the case that some imageswere discarded and why they weredestroyed.

Because digital cameras tend tohave poor image quality in the bright-est portions of the scene being record-ed, the SSOP advises the patrol officerto weaken the flash during close-upshots. This is a simple process andresults in much better photos.

Compared to 35mm film, digitalcameras produce lower-quality imagesin areas such as resolution, dynamicrange and color fidelity. For this rea-son, a digital camera should not serveas the primary photographic device torecord a major crime. The SSOP forthe photo specialist is restricted toworking with images from patrol offi-

cers. If a more advanced photographerwill be taking the digital images, aphoto specialist can use many addi-tional tools to extract informationfrom the photos. In this case, suchtechniques should be defined in thedepartment’s SOP.

Once the photos are taken, an SOPshould indicate that the images may bereviewed on the camera’s viewingscreen but may not be viewed with adevice that enables editing the photos.In order to change an image, a personmust be able to view the photo and

have access to tools that can alter it.The camera viewing screen allows anofficer to review the images but doesnot support editing. Strict adherence tothis rule makes it impossible for anofficer to alter the images.

Viewing images on a laptop com-puter in a squad car enables an officerto see and modify the images if hedesires. For this reason, doing thisshould be avoided. In special cases,where immediacy is important at thescene, an investigator can view dupli-cates of the images on the camera’sflash card. However, the flash cardfiles themselves should not be openedor changed in any way.

Chain of evidenceAn SOP should detail fairly stan-

dard provisions for turning over evi-dence. Such standards ensure that theevidence will not be subjected todoubts easily should it become neces-sary to perform scientific or mathe-matical analyses of the images.

An SOP for digitalimages should detail

the standard provisions for turning

over evidence.

Creating the digital image SOP

June 2000 • Law Enforcement Technology 61

June 2000 • Law Enforcement Technology 62

The sample Photo Specialist SOPspells out a process to retain a set ofunopened images. This means theoperator will be able to swear in courtthat the files were never opened. Sincea person cannot edit images that arenot visible, even if the tools are avail-able, the integrity of the unopenedimages cannot have been breached.Making the standard operating proce-dure a strictly adhered-to process ren-ders the operator’s testimony muchmore believable.

The photo specialist then placessets of images onto a serial-numbered,unalterable CD as soon as possible.This, too, makes image manipulationless likely. An officer cannot make animage show particular things if hedoes not know what those things are.Archiving the images before the caseis well understood supports this fact,which in turn supports a position ofnot altering the images.

A minor point, but one that couldbecome important should a case turnout to be more complicated than firstanticipated, is to use proper nomencla-ture in all records. When the camera’sbutton is pushed, an electronic file iscreated inside the camera that is notvisible and will soon be discarded.This file will be replicated a few timesin order to ultimately make an archiveversion and a visible, print version.But none of these files will be keptexcept for the archived replica. Thesetemporary intermediates are called“Primary Images.” They are prelimi-nary steps toward the creation of anarchived “original image.” This isslightly different from the way inwhich the Federal Rules of Evidencetreat traditional silver-halide photogra-phy. But it is expected that these rulesalso will be updated to deal with fea-tures inherent in new technology inthe near future. Meanwhile, it isimportant to keep the nomenclatureconsistent. An SOP should detail howimages at various stages are named.

However, the SSOP omits manyspecific operational steps because it isassumed that an individual utilizingthe process already has had training onoperating the equipment and softwareinvolved. There is no need to clutterup an SOP with a number of tedious,repetitive steps.

There are several complex technicalissues that one can encounter in usingdigital imaging technology. However,

it i s a rela tively s tra ightforwardprocess to make digita l imageryamenable to use in law enforcement.Rather than just hoping each officerwill sort out the complexities correct-ly, IFI advises agencies to write SOPsthat eliminate the guesswork. An SOPthat anticipates most of the issues anddeals with them in advance minimizesthe opportunity for evidentiary challenges. ❒

Herb Blitzer founded and now servesas executive director of the Institutefor Forensic Imaging (IFI), a non-profit organization dedicated to facili -tating effective use of imaging tech -nology in the field of criminal justice.He is a member of the ScientificWorking Group on Imaging Techno-logy (SWGIT). To obtain copies of thesample SOPs, contact the IFI at317/278-1669.