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Chuck Pruitt's Testimony

Charles (Chuck) Pruitt was the prosecution's expert on digital imaging. His qualifications were that he runs the Virginia Department of Forensic Science photo lab and had done photography for sixteen years. He has authored no books or magazine articles on the subject, nor any technical papers.

Pruitt's first testimony was about altering dates/times in EXIF data on digital images. He said that software to read the EXIF data on files from Canon 10D cameras was not readily available and that he had been forced to get the special software from Canon USA to even read the data. He then testified that he had done "extensive research" and had found that software to edit the EXIF data did not exist until November of 2003. He identified this software as EXIFER. He proceeded to say that even with EXIFER it would have been very "labor intensive" and would have taken days to change the times on 617 photos.

In his first testimony he insisted that the IBM Microdrive he was holding in his hands was not a Microdrive but a Compact Flash Card, even though it clearly was labeled as an IBM Microdrive.

When asked by the prosecutor if it was possible to preset a Compact Flash Card or Microdrive so that the camera would begin at a particular number he answered "Oh yes."

The Facts

Pruitt did not need any special software to view EXIF data. He claimed familiarity with Photoshop and could have viewed EXIF data with that. Or he could have downloaded viewing software free from Canon's website. Chuck Westfall from Canon testified that the printouts Pruitt showed were not made with any Canon software. (Pruitt was unable under questioning to give the name of the person at Canon who supposedly sent him the "special software.")

EXIFER is freeware. It was first released in 2001. If Pruitt had done any research at all, he would have gone to the EXIFER website,' where the full history of the software is shown. He would also have e-mailed the creator to verifY this, as I did. He would also have found out that EXIFER is designed for batch processing. If he had downloaded EXIFER and tried it, he would have found that it could change the times on 617 images in under ten minutes.

The numbering on the Compact Flash Card or Microdrive is a function of the camera, not the media. There is no way to preset an empty card to force the camera to begin numbering files at a particular number.

Pruitt's testimony would be laughable if it did not impact on my life. The man is obviously not an expert on digital imaging, and showed only a very vague familiarity with its concepts and terminology. But my expert who countered his testimony with the facts did not have the prestige of working for the Department of Forensic Science, and was ignored by the jury.