From - Fri Dec 06 22:43:31 1996 From: "Joe Riley" Newsgroups: alt.conspiracy.jfk,alt.conspiracy.jfk.moderated Subject: Zapruder Authenticity -- Part II Approved: jmcadams@netcom.com Date: 6 Dec 1996 18:11:41 GMT Organization: INTERNET AMERICA Lines: 230 Message-ID: <01bbe3a0$d6db7640$800e42ce@rdillard.sprynet.com> X-Newsreader: Microsoft Internet News 4.70.1155 Content-Type: text Content-Length: 10187 Status: O Originator: jmcadams@homer.thenet.net NNTP-Posting-Host: 206.64.182.2 Path: mcadams.posc.mu.edu!jmcadams On the Authenticity of the Zapruder Film -- Part II In a recent widely circulated email, Jim Fetzer (moderator of the Zapruder panel at JFK Lancer) refers to "Joe Riley's irrational rejection of the findings presented during the Zapruder Film Symposium during the JFK Lancer Conference". What I reject the notion that the Zapruder film has been _proven_ to be a fake; what I fear is that the critical community will loose all credibility if a speculation is accepted uncritically as "proven". I leave it to the reader to determine if my reasons are "irrational". The following is not exhaustive but representative of some of the issues that are at best unresolved in my opinion. [In the points that follow under "Example:", the numbered points refer to page 6 of David Mantik's handout at JFK Lancer, in the section labeled "Z Film: Peculia Data Now Explicable, Photographic." See appendix for the other points that were listed.] 1. Lack of Control material or studies Before one can state that something is abnormal, one needs to know what is normal. The presentations were based solely on the Zapruder film (with some comparisons made with the Nix and Muchmore films). This is especially true when dealing with such issues as the appearance of images in the sprocket area etc. (see below). To his credit, David Mantik agreed during the Q&A session that control studies need to be done. 2. Faulty data analysis, aka, just plain wrong. Example: "7. Greer head turns" The "unbiological and physically impossible" rapid head turn of Greer simply doesn't exist. Whereas it looks like there is a rapid head turn in low magnification images of the pictures (i.e., both the film and in pictures printed in Life magazine), when the images are enlarged by computer, it's clear and indisputable that this is nothing more than a distorted impression. You can see Greer's head turn in a normal sequence. At least two researchers who were part of the "closed" Zapruder meeting agree that the "rapid head turn" argument is "nonsense". 3. Failure to consider alternative explanations. Example: "2. Enlarging Stemmons sign: Z212-218" The issue is not so much if the sign "increases in size" (i.e., increasing horizontal measurements) but what may account for this increase. The following is a message I sent to Martin Shackelford about this issue; at the very least, it strikes me as a possible explanation for the increase. [It also supports the notion, I hope, that there can be a rational and reasonable exchange of ideas and information on this issue. I have edited out parts of the message that did not deal with the issue at hand.] =================== begin message============================= From: Joe Riley To: Martin R Shackelford Subject: Sign magnification in the Zapruder film Date: Wednesday, December 04, 1996 3:08 PM Martin: I know you are a careful and responsible researcher, so I have no problem accepting your measurements as accurate (within the limits of normal human variablity). I'll probably get around to doing my own measurements just to be a good empiricist, but I trust your ability and integrity. So, the issue at hand is not IF there is a difference but what may account for it. I'd like to discuss an alternative explanation with you and see what you think. Let me start by restating the obvious, since it's your data and I'm sure you know it well: 197 17 198 17.25 199 17 200 17 201 17 202 17.25 203 17 204 17 205 17 206 17 207 16.75 212 17.75 213 17.75 214 17.75 It's pretty clear that there are two distinct populations with little (or no) variance within each population and meaureable difference between them. No argument there. One useful approach is to see if something correlates with these changes (which, by itself, means nothing, but it's a useful first start). There is something that correlates and it implies an alternative explanation for the magnification. I couldn't find my Power CD (long story) but I go over to Mary Ferrell's daily as part of another project. Today I had a chance to look at WC Vol. 18, which has the Z frames printed. My observations are based on looking at the pics in the WC volumes; there's a chance that some of the things won't be clear in the CD-ROM version, but hopefully you have access to a copy and can check anything I say against the WC version. What correlates with the two populations (besides being pre- and post-splice) is that in 212 on, the left (I'm orienting relative to looking at the picture) side of the sign is in the sprocket area whereas it is not in the spocket area in 197-207. Again, that's a correlation and by itself means nothing. However, when one compares the sprocket area image with the "non-sprocket" image, there are clear differences. The sprocket area image is distorted relative to the n-s image. This is seen quite clearly (in the WC volumes anyway) where there is a "double image" of the left verticle pole of the sign but not of the right pole. The left pole is measurably wider (I didn't have a micrometer, but the difference is distinct simply by overlaying the width of one on the other). There are additional "distortions" that are visible on the sprocket/non-sprocket line (where they "join"), e.g., see 215 and 216 where part of the motorcycle appears to "hang over" the sign. I think we agreed that "double images" in the sprocket area were artifactual (with regards to motorcycles anyway). It seems to me that the change in relative size of the sign might also be an artifact of the image in the sprocket area. Clearly, the left vertical pole is blurred in such a way that it is "larger" than the right pole to the point where a double image can be discerned. Assuming that this is true for the sign as well, this may well account for the relative increase in the sign's measurements. Whatcha think? ====================== end of message ======================== 4. Inference without supporting data Example: "1. Foreground-background discontinuity" [presumably the crowd on Elm street] There is a "lack of movement" in the crowd seen in the lower left part of the film near the freeway sign in contrast to the crowd movement seen in the upper part of the film. It was suggested that this may indicate that the crowd in the lower part of the film may have been inserted in some manner to disguise some event. Without bothering to characterize this line of thought, what is lacking is any evidence to support such a speculation. A couple of things come to mind as examples of what could be done to test this "hypothesis", e.g., some sort (any sort) of indication on the film of "insertion" or comparison of the locations with other pictures (are people shown in other pictures in different locations and/or positions than they are seen in the Zapruder film?). 5. Failure to identify artifacts Example: "8. Single + double images in same frame" Some of the "odd" things seen in the film have simple explanations, i.e., double images produced by "sprocket slippage". To his credit, David Mantik acknowledged this possiblity in his talk (based on information supplied in the closed session) and agreed that further study was needed. 6. Arguments that depend on specific interpretations and become circular Example: "3. Absence of occipital defect after Z313" It is not very useful to use one interpretation as support for a second interpretation; the fact that there is an "absence of occipital defect" is not evidence that the film is faked unless one rejects the autopsy photographs and X-rays too. There is nothing inconsistent with what is seen in the Zapruder film and what is seen in the autopsy X-rays and photographs. A consideration of the Bethesda/Parkland descriptions is beyond the scope of this note, but those interested should read Gary Aguilar's papers that have dealt with this topic. One point to be made here is not to get into the debate over the medical evdience but to point out that this type of argument does NOT resolve anything. An equally valid interpretation is that the Zapruder film supports the notion that the medical evidence is authentic. NOTHING IS RESOLVED; there is no meaningful difference in the data that allows one say it is or is not evidence for a particular interpretation. It is, in the strict scientific sense, meaningless. Let me be clear: what I object to is the assertion that it has been proven that the Zapruder film is a fake. I am not and have never claimed to be an expert on film in general or the Zapruder film in particular. So, it is even more distressing to me that it is asserted that it has been _proven_ that the Zapruder film is a fake. I was distressed at the conference by the number of people who seemed to feel that this was the proper conclusion to what was presented. I object on scientific grounds to this conclusion. Hopefully, people will consider these points and realize that there are remaining questions because if this becomes the "consensus" of the critical community and is demolished because it was not examined carefully and cautiously, it will be the end of any credibility that we may have as a movement. Appendix: Points listed in "Photographic" section of "Z Film: Peculiar Data Now Explicable", handout by David Mantik at JFK-Lancer, page 6. 1. Foreground-background discontinuity 2. Enlarging Stemmons sign: Z212-218 3. Absence of occipital defect after Z313 4. Head snap 5. White object in grass 6. No posterior airborne tissue debris 7. Greer head turns 8. Single + double images in same frame 9. Jackie's torso and arm: Z315-317 10. Jackie's hand: Z326-328 11. Moorman-Zaprduer disparity 12. Image eccentricity during head shots 13. Image of right motorcycle 14. Right tail light on--9 frames (Muchmore) 15. Image clarity changes in successive frames 16. Relative blurring of limousine-motorcycle 17. Bronson-Zapruder discontinuity 18. Muchmore-Zapruder disparity > > 19. Motocycles overtaking limousine > > 20. Partial head absence: Z327-330 > > 21. Lamppost images > > 22. Numerous oddities: Z315-316