Natural process, yes. Accidental, no. The the latest science says that the image is the result of a photochemical reaction in the first few molecular layers of the individual threads.
This geometry and chemistry can only be formed by a hugely intense very short pulse of deep UV radiation. There was nothing 2000 years ago capable of producing such a pulse, and certainly not from a dead human body....unless.....
Note...I'm a chemist and spectroscopist, so have fairly good grounding in the science.
Au contraire, a very small degree of ionizing radiation over a very long period of time ... the long period of time which, according to the Byzantine history of the Mandylion, the cloth remained in hiding in the walls of Edessa. Radiation from radioactive elements that occur naturally in sedimentary rock, of the sort used to produce statuary.
Hope all is well, sirrah.
So am I (PhD in it), and observe that however and whenever this piece of linen cloth received the markings discernable on it, some of they may have been by blood-staining it (which would have been through and through), but widely and generally the visible differentiation must be due to the formation of either molecular color centers, and/or local carbonization of the cellulosic flaxen fibers.
Any shading perceived as depth of features must be studied to determine how the color centers were formed, and whether or not by radiation damage from an external source.
It is incredible to me that the markings do not display the variations due to folds in the cloth over raised features.
In analyzing the markings, any resulting from blood stains should be clearly localized and separated from other visible marking, and each studied as separate entities.
Regarding exposure to excessive heat in the silver container, was any of the cloth exposed to silver vapor or other to the effect of other metallic impurities in the molten (~1000 oC) state. And what about the vapors and particulate smoke generated by burnt natural fibers in the heating of the silver coffin?
Etc.
So far, I see the estimations and lines of attack being puerile, shallow, and not worthy of having been addressed by the true science method. Of course, the worshiping of this piece of cloth has prevented its submission for direct thorough examination, non-destructive or destructive, by thoughtful and experienced professionals.
What is patently obvious in this matter is that the superstition of Roman Catholicism proceeding from the papal oversight has so thoroughly ruled that impartial analysis and impassive conclusions have not been permitted.
Getting embroiled in argumentation over it is asinine. The essence to development of spiritual maturity is not even zero--it is negative, fit only for the natural soulish human who cannot receive the deep things of the Spirit of God, because they are foolishness to him/her. The Shroud of Turin has no spiritual significance. Engrossment with it is entirely carnal, not to be disregarded, but only fit for those whose perception and belief is limited by their lack of regeneration in the Spirit.