Date: 07-18-91 23:16 Subj: Thread: Photos as evidence Saw this on sci.skeptic while on Use

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Date: 07-18-91 23:16 From: Don Allen Subj: Thread: Photos as evidence Saw this on sci.skeptic while on Usenet and thought it might be interesting to post here: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Article 7620 of sci.skeptic: From: kambic@iccgcc.decnet.ab.com (George X. Kambic, Allen-Bradley Inc.) Newsgroups: sci.skeptic Subject: Use of Photographs as evidence Message-ID: <1991Jul16.132821.5145@iccgcc.decnet.ab.com> Date: 16 Jul 91 18:28:21 GMT Article-I.D.: iccgcc.1991Jul16.132821.5145 Lines: 13 There have been a number of recent comments about the use of photographs as evidence for whatever. I am far from an expert on this, and it would be good to get some expert commentary, but the value of photographs is being reduced by image processing techniques. From some of the work that I have seen (and no doubt superceded by work in the DoD labs), essentially any visual image can be digitized, reprocessed, combined with any other visual image, and recopied as an analog photo. The methods by which such a photo can be identified probably are not simple. Scaling, repositioning, lighting, shadows, even expressions, can be altered, with the result being a rather credible photograph that literally did not happen except in the mind's eye. GXKambic standard repositioned digital disclaimer Article 7635 of sci.skeptic: From: revpk@cellar.UUCP (Brian 'Rev P-K' Siano) Newsgroups: sci.skeptic Subject: Re: Use of Photographs as evidence Message-ID: Date: 17 Jul 91 23:11:22 GMT References: <1991Jul16.132821.5145@iccgcc.decnet.ab.com> Sender: bbs@cellar.UUCP (The Cellar BBS) Organization: The Cellar BBS and public access system Lines: 34 kambic@iccgcc.decnet.ab.com (George X. Kambic, Allen-Bradley Inc.) writes: > There have been a number of recent comments about the use of photographs as > evidence for whatever. I am far from an expert on this, and it would be > good to get some expert commentary, but the value of photographs is being > reduced by image processing techniques. From some of the work that I have > seen (and no doubt superceded by work in the DoD labs), essentially any > visual image can be digitized, reprocessed, combined with any other visual > image, and recopied as an analog photo. The methods by which such a photo > can be identified probably are not simple. Scaling, repositioning, lighting, > shadows, even expressions, can be altered, with the result being a rather > credible photograph that literally did not happen except in the mind's eye. > > GXKambic > standard repositioned digital disclaimer I first heard of digital retouching through a cover story in the Whole Earth Review a few years back-- in fact, their cover photo was of a trio of UFOs flying over San Francisco. They made a point of putting the objects behind things like fire escapes and the like, to confound people who were looking for the standard 'tricks' of trick photography. Apart from the lack of haze and some perspective on the furthest objects, it ooked VERY convincing. Exactly HOW to spot such fakes might be beyond me, because I keep thinking of ways to get around it. As long as one can manipulate the photo at a resolution level higher than the source film, then anything's possible. """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" Brian Siano, Delaware Valley Skeptics Rev. Philosopher-King of The First Church of the Divine Otis Redding revpk@Cellar.UUCP "Ecrasez l'enfame!" - Voltaire """""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""" Article 7639 of sci.skeptic: From: ncliffe@hfserver.hfnet.bt.co.uk (Nigel Cliffe) Newsgroups: sci.skeptic Subject: Re: Use of Photographs as evidence Message-ID: <1991Jul18.085811.3135@hfnet.bt.co.uk> Date: 18 Jul 91 08:58:11 GMT References: <1991Jul16.132821.5145@iccgcc.decnet.ab.com> Sender: news@hfnet.bt.co.uk (News Administrator) Reply-To: ncliffe@hfserver.hfnet.bt.co.uk Organization: British Telecom Lines: 28 From article <1991Jul16.132821.5145@iccgcc.decnet.ab.com>, by kambic@iccgcc.decnet.ab.com (George X. Kambic, Allen-Bradley Inc.): > There have been a number of recent comments about the use of photographs as > evidence for whatever. I am far from an expert on this, and it would be > good to get some expert commentary, but the value of photographs is being > reduced by image processing techniques. From some of the work that I have > seen (and no doubt superceded by work in the DoD labs), essentially any > visual image can be digitized, reprocessed, combined with any other visual > image, and recopied as an analog photo. The methods by which such a photo > can be identified probably are not simple. Scaling, repositioning, lighting, > shadows, even expressions, can be altered, with the result being a rather > credible photograph that literally did not happen except in the mind's eye. > > GXKambic > standard repositioned digital disclaimer In support, no doubt readers are aware of the infamous incident of the 'Fairy' photographs of the 1920s. These show a young girl looking at some fairies infront of a waterfall. They convinced many at the time, including Sir Authur Conen Doyle. They were faked. One of the girls who did it admitted such many years later. It didn't need careful doctoring, just careful positioning of the subjects in the photo. - Nigel. -- Nigel Cliffe, Human Factors, BT Laboratories, Martlesham Heath, Ipswich, IP5 7RE, UK Email: ncliffe@hfnet.bt.co.uk Tel: +44 (0)473 645275 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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