By George S. Pearl
  Whether due to mistakes or misrepresentations, thousands of the photographs used on a daily basis in our courts and the insurance field are incorrect. Ignorance and apathy seem to play a large part in this problem. Law schools neglect to teach this vital area in depth. Almost everyone has a camera, and can take a photograph. Many attorneys feel that rather than hiring an expert to perform needed services in an unbiased manner, they can do just as good a job themselves, or worse yet, they simply tell their clients to 'get some snapshots'.
   One of the most commonly used pieces of evidence in modern trials is the photograph. All that is presently required is for a witness to testify that a photograph is a fair and accurate representation of what it shows. This is a very simple demand to make of a document containing a historic recording with variables such as lighting, color, perspective, foreshortening, selective focusing, viewing angles and coverage, speed control of moving objects, compaction and expansion of objects and time, magnification, and with even the potential to depict what cannot be seen by the eye at all.
   The problem is serious and we, as experts in the forensic fields, should certainly be aware of some of the pitfalls in using this wonderful tool of photography in our work. One of the main mistakes in using a photograph as evidence is viewing the photograph, slide, motion picture, or even video presentation incorrectly. When a photograph is intended to show relative distances from one object to another, perspective, or depth, it is paramount that the picture be viewed at the correct distance or it will be totally misrepresentative.
   Correct viewing distance can be determined by first measuring, in inches, both the negative and the focal length of the lens used. For example, a photograph taken with an 80mm lens on a 2 1/4 x 2 1/4 film format camera depicts 150 feet of skid marks. You wish to be represented correctly in a photograph viewed while hand held at approximately 14 inches. To convert the 80mm focal length of the lens to inches, divide by 25.4. We have a lens 3.15 inches long. The size of one side of the negative is 2.25 inches. To find the proper enlargement for a viewing distance of 14 inches, divide the viewing distance in inches by lens focal length in inches (14 divided by 3.15) and we arrive at 4.44. This is the number the short side of the negative (in this case 2.25 inches) must be enlarged to produce a print to be viewed correctly from 14 inches away. Multiplying 4.444 by 2.25 we arrive at 9.99 or approximately 10 inches. Our print size should be 10 inches by 10 inches.
                     Thus the formula is :
                VIEWING DISTANCE + FOCAL LENGTH =
         X MAGNIFICATION of the NEGATIVE OF THE LENS
   Using this same formula, if the skid mark photograph is to be shown to people viewing it from about 12 feet away, such as a jury, this same photograph should be enlarged to a size of approximately 103 inches by 103 inches to maintain the same perspective and apparent length of the skid marks. Any photograph smaller than this would make the skid marks appear much longer than they really were. The same procedure should be used for movies, slides, and video presentations.
   One misconception among those of the legal profession is that legal photographs must be taken with a 'normal' lens. Wrong ! As long as the above formula is adhered to, the same scene will look exactly alike in perspective, whether taken with a wide angle lens, 'normal' lens, or telephoto lens. Only the angle of view changes, not the perspective. We even use panorama cameras in our work which have a viewing angle coverage of 140 degrees. When viewed correctly, one sees in the resulting photographs exactly the same perspective as would observers at the scene turning their heads from far left to far right. This is a very useful tool for crime scenes, condemnation cases, auto accidents, driver's eye view, and the like.
   Since the above rule of correct viewing of the photograph is not known or not followed by most trial attorneys, it is a rather simple task for a photographic expert to testify to the inaccuracy of the opposing counsel's photographic evidence. Thus, many times it can be used to prevent admittance of that evidence.
   With such shows as Stars Wars being produced, one can readily see that just about anything can be done with a photograph to make it show extremely believable, but false, information. One of our cases in this area involved a plaintiff who had a makeup artist alter her face to look as though she had been brutally beaten. The photographs which were entered into evidence months later confirmed her story. They had been taken with a polaroid camera, as so many of this type are. Upon examination of the photographs, I was unable to detect that the bruises, etc. on her face were not genuine, but the code printed on the rear of each Polaroid snapshot became most valuable. This code specifies production run, the machine which made the film, and also the date of manufacture (the exact work shift if necessary). Upon breaking down the code, I was able to prove that the film used to take the injury photographs was not in existence until almost a year later. Case solved.
   There is a high photograph-fraud rate today in the insurance business. Claims are made for property losses that were not as severe as shown in photographs used to substantiate these claims, or that did not occur at all. Many insurance fraud cases come along with photographs to prove that the claimant owned the items that were 'stolen'.
   Luckily, most of the people who try this are in a hurry to get fast money, and use either Polaroid or Kodak instant photographs to back up their claims. As mentioned before, the Polaroid photographs all have a code printed on their reverse. When inspected, they will often reveal that the photographs were taken much later (sometimes years) than the date stated by the claimant. To decode Polaroid photographs call ALPS at 1-800-873-2577 pin 2577.
   Kodak instant prints, before a certain cutoff date, also contain this same vital information. But when viewing the back of a Kodak instant print, ones sees only a black plastic covering. Again, you may call ALPS for assistance in decoding these photographs.
   There have been cases involving one or more photographs that have been altered by the use of wet dyes or retouching dyes and airbrushing in, or out, certain areas in a photograph. An example of this would be a picture showing liquor bottles all over the inside of a car taken right after an accident, but when the photographs are shown in court, there are no liquor bottles present. Or even a photograph where the hands of a clock have been changed. Don't think that this sort of thing does not happen very often. It is just that we are not tuned into looking for it, or knowing what to look for.
   When a photograph has had artwork done to it, the print will probably be sprayed with a lacquer finish to protect and hide the artwork. Wet dyes and airbrushing can be detected by holding the print up to a strong light and viewing it through to note any dark areas, or removing the lacquer protective coating with lacquer thinner, and then washing the print, or in some cases rephotographing the print with infrared film to expose the hoax.
   None of the above methods will harm the photograph if done correctly. However, this is not an endeavor for an amateur. Call ALPS for expert advise.
   There are some methods of altering photographs which when done by a good technician are all but impossible to detect. One of these is the matte box method, whereby 2 people who have never met can be shown talking to each other. The same sort of thing can be done with special masking, paste ups, and rear projection. Persons can be shown in a photograph in a location where they have never been before. This is why it is so important in legal cases that negatives be preserved, although even negatives can be made just as fraudulently as prints by recopying the prints following alterations to produce a new set of negatives that can be said to be genuine.
   Bruises, in personal injury cases, can be made to look much worse than they really were by custom color printing. Road signs can be made to all but disappear through the use of filters. And one of the biggest threats to correct rendition is that of night vision photographs made by one who is truly not an expert at producing these exacting photographs or movies. Night vision photography, or the photography of what one could or could not see at night, is extremely delicate. For this type of photograph to hold up in court it is very important that the amount of illumination shown in the photograph or motion picture can be related to a known standard, and that all conditions of lighting have been reconstructed correctly. Beware.
   I hope that this has made you more aware of misleading photography in your work, and that the next time you hear the old phrase "photographs never lie", you will disregard it. A camera in the hands of a liar will speak as its master.

George Pearl, President of Atlanta based ALPS Evidence & Photo, is a certified evidence photographer and a fellow of the Evidence Photographers International Council and Certified Professional Photographer of the Professional Photographer of America. He is a Certified Questioned Document Examiner and Handwriting Expert with the Association of Forensic Document Examiners. He also serves as a board member of the Demonstrative Evidence Specialist Association dedicated to maintaining the highest standards in the production of demonstrative evidence.

note: The article EVIDENCE PHOTOGRAPHY : The Giant Killer also covers information about proper viewing distances.

WARNING : This article was contains information about tests to photographs and documents which if performed incorrectly probably will result in the destruction of the original photographs and documents. This article is in no way to be misconstrued as a 'how to' guide and be advised that you should seek expert attention to any of the procedures herein.

* This article was first published in THE CHAMPION, 1981.