Before digital imaging, photographs were recorded on a negative from which any number of prints could be made. It is virtually impossible to alter a negative without leaving clear evidence and consequently the negative could be used as a “master copy”, so that it could be produced for evidential purposes if needed. Now that the use of film has been so widely replaced by digital imaging the important question remains: “What is the master copy”?

If there is a dispute regarding the validity of an image and in particular whether or not it has been adjusted in any way, then what can you produce to show that the image is an accurate representation of the subject? This is a big theoretical question for anyone working in matters that might result in litigation but it is also a matter of some practical concern as was shown when a motorist successfully overturned a parking conviction because the car parking company concerned had doctored a digital image.

Kevin McGuire said that when he had parked his car in a legitimate spot there was no sign saying that the parking bay had been suspended. When he returned to his car he had been given a parking ticket and there was a sign on a nearby street lamp suspending the parking bay. At the hearing the parking company produced a photograph that they had taken of the parking notice the day after Mr McGuire had been fined and a photograph showing what they said was the same notice on the day before his “illegal” parking. The date stamp on both photographs and the date on the sign appeared to show that the notice had been there the day before Mr McGuire parked. Unfortunately the company concerned had omitted the fundamental point of the clouds in the background which were the same on both photographs clearly indicating that something was amiss!

So, how do you make sure that nobody can challenge the validity of your digital photographs?

The only authoritative guidance on the subject comes from a Home Office document entitled “Digital Imaging Procedure”. It deals with the subject for criminal cases but the same procedures apply just as well to civil cases. The guide acknowledges that there are difficulties with the technological encoding of photographs to show that they are genuine originals and that technology will change very frequently making it difficult to set a standard.

Instead the guide sets out a procedure for the auditing of the original so that somebody can swear to the authenticity of the image. The procedure centres around a simple but effective audit chain:

1. When using the camera do not delete any images. Deleted images will show up as gaps in the record raising the question “Why were they deleted”? Even if a picture comes out horribly wrong leave it in there for the audit trail.
2. As soon as possible make a Write Once Read Many (WORM) copy directly from the camera onto a CD or DVD. The importance of making the copy directly from the camera rather than loading the images onto a computer hard drive first is that the copy on the hard drive will at some stage be deleted so that you cannot show that the WORM copy is the original.
3. The disc should be labelled with the case details, date, the phrase ‘Master Copy’, your signature and the date on which the master copy was created. That master disc should then be put into secure storage and only used for the purposes of creating additional working discs. Any subsequent copies should be labelled as working copies with the date of their creation and logged in the case file so that every disc can be traced and numbered.

The situation becomes slightly more complicated when a computer hard drive is to be used as the master copy. This is normally only done when large numbers of images are being stored.

In summary, copy your images as soon as you can directly from the camera onto a CD or DVD and keep that CD or DVD as the master copy. Keep notes giving an audit trail of what you have done and when you have done it.

Following these procedures will show a court that you know what you are doing. They also go a long way towards safeguarding your images from loss or corruption as a result of the theft of your camera or the breakdown of the storage medium. Imagine having your camera stolen with 15 or 20 cases worth of photographs stored on it because you had not yet transferred them!

If you would like further information on the storage of digital images then email This e-mail address is being protected from spambots. You need JavaScript enabled to view it