Alternative name (afterthought, added 25th April): this new technique produces what might be called a "tactile chemograph". Maybe there was only one ever produced (the image that we now call the Turin Shroud). The tactile chemograph may be thought of as a forerunner of the photograph. (In both instances, one produces a latent image from a real person without harming them in any way, one that can then be developed in a bath (or vapour chamber) with the appropriate developing chemicals.
Details will follow. That's if anyone is interested (comments invited- see sidebar for quick link). If not I'll leave it at this - short and (arguably) sweet and take a holiday from scientific model-building for a while (weeks rather than days). It can be an exhausting business, and somewhat hazardous too when fumes off concentrated nitric acid are my suggested means for producing the elusive result - that 'enigmatic' and highly superficial Shroud of Turin image - at least at the macro level.
Reminder (from posting preceding this one):
Step 1:Imprint off 3D template (possibly a real person, living or dead OR an effigy thereof in wood, stone, clay etc) painted with heat-gelatinized white flour.
Step 2. Develop the proto-image by exposing to nitric acid (HNO3) fumes
Step3. Neutralise the unreacted acid in the fibres (e.g. by dusting with chalk, or rinsing with lime water).
Here's an earlier picture showing the crucial testing of the third step (neutralization of acid) performed on the unsightly excised portion of the hand imprint.
The portion on the right is the untreated control, i.e. hand imprint after partial dissipation of nitric acid fumes in air (outdoors!).
The left hand portion was cut off between the two crosses. That.s when I noticed the stiff nature of the image area with a coarse texture (hardly surprising, given that flour is mainly starch). Would the stiffness disappear if the cloth were washed, while leaving the image? But first, there was another test that could be done before wetting the fabric. I crumpled and kneaded the fabric. Immediately the fabric in the image area began to disintegrate, assisted no doubt by the presence of the stiffening agent that assisted thread fracture. All the more reason, then, to minimise the weakening of the linen by getting the fabric from the fumigation chamber into a weak alkali solution ASAP. The left hand portion in the photo above was the appearance AFTER doing just that - immersing the offcut in sodium bicarbonate solution, testing before and after with pH indicator to check that acid had been neutralised, then rinsing thoroughly and drying. Not only had the image not washed out, but it had intensified and changed from yellow to yellow-brown, becoming arguably more Shroud-like.
Expect some more experimental details to be added in the next day or two, plus the results of imprinting off a miniature effigy made from moulded clay (after air-drying and sealing).
That's the home-made template on the right, alongside the brass crucifix used in so many of my previous "heat scorch" experiments. Quick-drying emulsion paint was used as a sealant (what would medieval folk have used to seal the pores of unfired earthenware on wonders?). Imprints are developing in acid fumes (locked garage) as we speak.
Some details re the imprinting technology thus far (as promised)
I used my right hand to paint the left one with a thick paste made the previous day using white flour and hot water (it set to a gel overnight in the fridge, which reverted to a paste on stirring). Linen was placed on top, as shown, and then pressed down firmly to produce an imprint on the underside of the linen. Note the considerable detail in the imprint, even at this early stage.
Here's an early stage in setting up the fumigation (garage! eye protection? face mask! ).
The linen with its flour imprint has been stuffed into the 'goldfish bowl', secured with the blue tape to leave a clearance between fabric and base to leave room for acid. The concentrated nitric acid (hazardous! not for the faint-hearted) is then introduced via the funnel so as to form a 1cm deep layer under the fabric without touching it directly. The idea is to funigate the image. After carefully removing the funnel a sheet of glass was used as a lid, weighed down to get a reasonable seal. The garage was then vacated ASAP and locked with a no-entry sign on door. Chemical development took place overnight.
Here's the imprint after development with nitric acid, but before neutralizing the excess acid. There's not a lot to see at this stage, and it's still a chemical hazard, needless to say.
Here's the developed imprint in the wash hand basin, ready for rinsing and neutralization of unreacted acid with sodium bicarbonate.
Ready to neutralize the excess acid.
The acid has been neutralized (the pH now being greater than 7). Already the image on the linen looks darker (now more brown than yellow).
All the photos on this posting are 'as is' from the camera. Apart from cropping, there have been no changes to brightness, contrast or other photoediting.
Afterthought: who'll be first to say that I've failed to produce a perfect facsimile copy of the fingers on the Shroud - that mine are ordinary everyday sort of fingers, not the spindly unnaturally elongated fingers one sees on the Shroud? As for the hint of fingernails on my image - well, that rules it out of contention straightaway! You read it here first.
Afterthought to afterthought: there's a simple answer to those overlong fingers on the Shroud. The subject was alive, say a non-deceased medieval monk, and his hands shifted during the imprinting process. Maybe the imprinter briefly applied to much pressure, causing the hands to slide on the slippery abdomen, creating a skid-mark effect, captured for posterity.
Update: Wednesday 22 April, 15:10
I have a new imprinting medium, a very different one from the flour gel used so far. It's of animal origin, not plant, it requires much shorter development times, and if I'm not mistaken, appears to protect the background non-image areas of linen (maybe 'trapping ' nitric acid more efficiently?). What's more it was well known in medieval times, indeed for millennia.
Here's what an imprint off my trusty brass crucifix looks like with the new wonder material after neutralizing excess acid, and applying the autocorrect menu option to the snapshot:
Here's a light/dark reversal, using the Edit Invert function of ImageJ (autocorrected for additional contrast).
Update: Wednesday April 22, 22:00
Here's a further responses or rather query, regarding the new model, appearing just now on shroudstory.com, and my immediate reply.
...and the last of those comments had this appended as a postscript, though how many get to see it when a single individual then posts 6 comments in short order (more on the way?) remains to be seen. This blogger NEVER forgets those who abuse blog sites that have a fixed number of entries under Recent Comments, in this instance 10 only.