Welcome to the Fourandsix blog, where you’ll find tips on image forensics techniques and commentary on issues relevant to photo tampering and the responsible use of imaging tools.
Hany Farid | Tuesday, February 5, 2013 at 6:00AM Last week I attended and spoke at the Computation + Journalism Symposium. This venue brought together technologists and journalists to discuss the role of technology in journalism and its impact on the future of journalism. By my count, there were four main themes that emerged from this two day event.
Hany Farid | Tuesday, January 29, 2013 at 6:00AM As I was walking to get lunch the other day, the top of a parking meter caught my attention (I’m weird, I know). It caught my attention because of the way that the highlight on the top of the meter moved as I walked past it. The highlight moved, of course, because the relative position between me, the meter, and the sun was changing. At the same time, the overall shading on the meter stayed the same. It struck me that the highlight and shading can each be used to reason about the location of the light source. It also struck me that digitally editing an object with a highlight could be tricky because it would be hard to make sure that the highlight, shading, and shadows are all physically consistent.
Hany Farid | Tuesday, January 22, 2013 at 6:00AM I was recently asked to help determine the provenance of several photos. What is not in dispute in this case is that the photos, dating back several decades, were taken at a historical event. What is in dispute is who took the photos. Two photographers, each of whom were at the event, claim to have been the person behind the camera. To further complicate this dispute, the photographers’ cameras are no longer available, and only prints from the original 35mm negatives are available. As I was sketching some ideas on how to determine who took the photos, I realized that under the right conditions, we can infer the height of the photographer from information only in a photo.
Hany Farid | Tuesday, January 15, 2013 at 6:00AM Videos from Russian dash cams have become a bit of a sensation. After our analysis of the baby-snatching eagle, we were asked by a reader to analyze a particularly shocking video (WARNING: video depicts a violent accident). After its release, the video sparked a vigorous debate regarding its authenticity.
Kevin Connor | Monday, January 7, 2013 at 6:00AM This past Friday, a controversy erupted over a photo distributed by the office of Nancy Pelosi depicting the 62 democratic congresswomen of the 113th U.S. Congress standing on the steps of the Capitol building. The photo was sent to the press as well as posted to Pelosi’s photo stream on Flickr. The controversy erupted because it soon came to light that four of the congresswomen pictured were actually added to the group photo in post-production using Photoshop. Some members of the public were deeply offended that the picture had been modified, and some members of the press went so far as to label the photo government “propaganda.” Personally, though, I have to admit that I was surprised by the controversy. In my opinion, this photo was clearly a staged arrangement of people rather than a spontaneous historical event. Should it matter how much of that staging happened in person versus in the computer?
