tag:blogger.com,1999:blog-4111782305190930044.post7134838798791737046..comments2023-10-19T04:59:08.088-07:00Comments on science buzz: The Turin Shroud - could it have been produced by thermo-stencilling?sciencebodhttp://www.blogger.com/profile/12051016731274875332noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-4111782305190930044.post-36553292329024952412012-01-09T02:21:11.298-08:002012-01-09T02:21:11.298-08:00Postscript:
Since this post was written, this blo...Postscript:<br /><br />Since this post was written, this blogger/retired science bod has proposed a more comprehensive theory as to how the Shroud was created in the 14th century as a ‘holy relic’. The essence of the theory is the making of a thermo-stencil, using linen impregnated with a heat-sensitive chemical substance or cocktail, from a partially-mummified, minimally-skeletonised cadaver possibly in a monastery (think Brno). The desiccated proxy for the crucified Christ would have been heated in an oven of some kind, until radiating sufficient infrared as to be capable of leaving an image on thermo-sensitized cloth. <br /><br /><a href="%E2%80%9Dwww." rel="nofollow">link to mummy theory</a>sciencebodhttps://www.blogger.com/profile/12051016731274875332noreply@blogger.comtag:blogger.com,1999:blog-4111782305190930044.post-64085942905262335522012-01-03T00:31:14.716-08:002012-01-03T00:31:14.716-08:00Afterthought: how superficial is my homemade scorc...Afterthought: how superficial is my homemade scorched image? Is there anyway that could be approximately gauged without using specialized equipment?<br />One could try abrading the surface lightly, say with fine-grade sandpaper, one stroke at a time, to see if the image can be removed without "roughing-up" the fabric too severely. Another idea has just occurred to me - to see whether the image can be stripped off with sellotape. That was the trick used to strip individual sheets of graphene off graphite - winning the discoverers a Nobel prize no less! Separation of the lamellae of graphite requires breaking the adhesive van der Waals forces between the carbon sheets, produced by temporary electrical dipoles which though much weaker needless to say than full covalent bonds, can be sizeable when there's a lot of them holding the two slices together. I'll give it a try later in the day, and may also experiment with applying charcoal as a water-suspended paste, i.e. painting it on the cotton with minimum applied force. Much depends on whether the char particles are bonded in any way to the cellulose matrix, or are free-standing, so to speak...<br /><br />Incidentally, my reading of the pyrolysis paper cited above would suggest that cellulose char ie scorch mark, is not elemental carbon ("charcoal") but polymeric material with hydrogen and oxygen as well as carbon. It might be better described as a resin rather than a "char". Clearly there is a lot more reading that needs to be done to get a better understanding of the surface scorching of cellulosic fabrics...sciencebodhttps://www.blogger.com/profile/12051016731274875332noreply@blogger.comtag:blogger.com,1999:blog-4111782305190930044.post-8034770736994624892012-01-03T00:09:26.776-08:002012-01-03T00:09:26.776-08:00Have posted this comment to "Shroud of Turin&...Have posted this comment to "Shroud of Turin" site re the claim there that heating could not have produced the image, based on what I would regard as somewhat tendentious reasoning and/or assumptions, eg. that heating would disturb the structure of otherwise unaffected cellulose:<br /><br />"I overlooked to thank MouseintheHouse earlier for agreeing to transplant a comment from my own blog prior to my (re)registering with WordPress, to say nothing of Dan Porter for responding to an email almost instantly with this post. Many thanks to you both.<br /><br />It seems somewhat uncharitable then, to say the least, to immediately take issue on the details, but hey ho, that’s science for you.<br /><br />While my knowledge on many of the issues is patchy, there is one apparent discrepancy that strikes the newbie quite quickly. On the one hand we read that the image is exceedingly superficial, scarcely penetrating into the fibres, yet above we read that if scorching were the mechanism then we would expect to see changes in the structure of the flax fibres. I do not see the latter as in any way self-evident, far less obligatory, if one supposes that scorching affects the most superficial top surface only. Indeed, if a sketched image in charcoal or a similar black pigment were used to absorb radiant heat, as I have suggested, that might also tend to restrict scorching to a very small depth of penetration, such that fibrils look relatively intact immediately below the scorched layer… In other words, the carbon particles serve to protect deeper layers.<br /><br />There is also a recent paper on cellulose pyrolysis that starts by listing the initial depolymerisation products – levoglucosan, furfurals etc – and then makes the interesting observation that char is formed by re-polymerisation of the decomposition products (rather than stripping out of volatiles, say, to leave a C-skeleton).<br /><br />http://pubs.acs.org/doi/abs/10.1021/jp906702p<br /><br />Given that the monomers for the secondary polymerisation are small molecules and volatile, at elevated temperatures they will tend to diffuse rapidly from their sites of formation into the surrounding air. So there are further grounds, albeit theoretical ones, for thinking that the scorched zone could be very superficial indeed, resulting in minimal damage to fibrils at a gross level observed by light microsocopy or possibly even SEM."sciencebodhttps://www.blogger.com/profile/12051016731274875332noreply@blogger.comtag:blogger.com,1999:blog-4111782305190930044.post-40942177366246529752012-01-02T03:52:16.300-08:002012-01-02T03:52:16.300-08:00PS: the site in question is Dan Porter's splen...PS: the site in question is Dan Porter's splendid "Shroud of Turin Blog" which has very generously devoted a post to my little experiment with the lamp and charcoal:<br /><br />Here's the link:<br /><br />http://shroudofturin.wordpress.com/2012/01/02/thermo-stenciling-the-shroud-of-turin/sciencebodhttps://www.blogger.com/profile/12051016731274875332noreply@blogger.comtag:blogger.com,1999:blog-4111782305190930044.post-48817172364822046892012-01-02T03:36:12.648-08:002012-01-02T03:36:12.648-08:00Thanks Mouse. I just tried responding to your same...Thanks Mouse. I just tried responding to your same comments over on Dan's site, but WordPress does not seem to accept my login and the commenst has not appeared.<br /><br />Here it is:<br /><br />"MouseInThe? is absolutely correct when he says that a thermal stencil image is a positive, not a negative, since dark charcoal-covered areas become dark scorched areas. I thank him for the opportunity to back-track a little on what I may have said previously, or at any rate to qualify it.<br /><br />To produce a Turin-Shroud like negative, one that becomes a positive on the photographic negative, then the hypothetical sketched image would have had to be drawn as a negative, with a reversal of light and shade, which is admittedly unconventional. <br /><br />But there may be strong practical reasons for doing so given the proposed technique: in a well-illuminated subject there will be a predominance of light reflective areas over ones that are in shade (eye sockets and the like). That would tend to give a scorch pattern with just a little scorch, but an awful lot of white space. By reversing lighjt and dark in the sketch, one ends up with something that makes a much bolder image but one that is still recognizable as a man, despite the reversal of light and shade.<br /><br />I hope that makes sense..."<br /><br />Could you oblige by cutting and pasting into Dan's blog. I'll try and sort out the WordPress thing later. Odd, because I am able to post comments to another WordPress blog without being pre-registered for that site...sciencebodhttps://www.blogger.com/profile/12051016731274875332noreply@blogger.comtag:blogger.com,1999:blog-4111782305190930044.post-46596848431051051082012-01-02T03:04:28.197-08:002012-01-02T03:04:28.197-08:00wait a minute that is not a negative and it can;t ...wait a minute that is not a negative and it can;t produce3D data, no it can;t. it can;t be doubly superficial or pixelated like the shroud.i;ll bet thermal stencil images fluoresce under UV light. try it. shroud images do not. major fail.MouseInTheHousehttp://shroud.comnoreply@blogger.comtag:blogger.com,1999:blog-4111782305190930044.post-46822934985206874172012-01-02T01:54:12.465-08:002012-01-02T01:54:12.465-08:00Well, you have raised the 3D angle, which I suspec...Well, you have raised the 3D angle, which I suspect will be a major one that needs to be addressed. I don't intend to say much until I've done some more reading. For the moment, I would just express scepticism re that term "coded information". If an image is photographed and then digitized into thousands of pixels for analysis, then what would the discovery of encoding mean precisely? Hidden coding in the original image, as implied, which seems improbable, or coding as an artefact of digitization?<br /><br />Is there not a sense in which the skill of the artist in making a 2D image seem at least partially 3D-like - through light and shadow to represent relief and contours - is to fool the brain's mechanisms in the visual cortex to "decode" images received as a series of nervous impulses from the retina. That might then be detected as "coding" after digitization, but merely reflect the skill of the artist in making 2D seems quasi-3D.<br /><br />"Coding" and "decoding" then is arguably a can of worms unless a clear distinction is made between what the brain is doing, as distinct from the computer of an image-analysis expert using his sophisticated but possible too-clever-by-half statistical and modelling techniques. <br /><br />I hope some of that makes sense. Thanks for the interest.sciencebodhttps://www.blogger.com/profile/12051016731274875332noreply@blogger.comtag:blogger.com,1999:blog-4111782305190930044.post-1774078257041331192012-01-02T01:37:04.437-08:002012-01-02T01:37:04.437-08:00Interesting. Didn't the Dutch Masters use the...Interesting. Didn't the Dutch Masters use the camera obscura to get perfect 3D perspective? An image copied carefully using charcoal and a camera obscura would obviously contain all the 3D 'coded information' which seems to be baffling the scientists. You could be onto something here...Anonymousnoreply@blogger.com