First, Thibault wrote:
Can you explain step by step your onion experiment ? I am not sure to understand well, but I see no connection with the scorch hypothesis on the Shroud.
I’m a little surprised I have to explain (all over again) what to me seems self-evident. Never mind. Let’s start again.
And it goes from there. For more on the subject see, Modelling the image of the Turin Shroud – an interrupted experiment using onion epidermis – just one cell thick, a posting on Colin’s blog from two years ago.