Here, in the low country of South Carolina, some of the best game fishing requires you to kayak or wade into the isolated murky salt water marshes. There, you will find the great and tasty Redfish that only sportsmen are allowed to pursue. Sometimes, searching through blogs for the best material seems similar. You must walk in, slog about, cast here and there, until you get a bite.
In this blog, Charles Freeman had commented that his hypothesis “is a plausible hypothesis and so needs to be tested out, just as the Oxford lab tested out John Jackson’ s hypothesis about carbon monoxide affecting the radiocarbon date and finding that it did not” and that “… the artist WAS trying to create a mirror image but that the apparent negative image is what is left when the pigments came off …”
Moreover, Charles had explained that this negative image came from shadows that remained when the pigment flaked away. Shadows? Shadows that remained?
It was in his own blog, deep in a posting on another subject, that Colin Berry chose to reply to Charles:
You may consider it a plausible hypothesis Charles. However, your plausible hypothesis required your making late-in-the-day qualifying assumptions, not only about total detachment of pigment leaving no traces for STURP to detect by microchemical testing. It now involves some wild speculation about pigment leaving shadows (why? how? what?). As if that were not stretching credulity enough we’re now told that thick paint leaves light shadows and thin paint leaves dark. "Plausible hypothesis" you say Charles, when it involves your building a house of cards, making qualifying assumptions that no one, least of all yourself, would have dreamed up that rider unless or until, er, painted into a corner. Last but not least you are looking to art technologists and historians to verify your hypothesis rather than physicists and chemists. Do you have these people at your beck and call, or will there be more who fail to answer your emails?
This not science. It is not even vaguely scientific. It’s an attempt to dress up a dud hypothesis with ever increasing layers of fantasy.
Give it up Charles. This is getting you nowhere, and for the rest of us is a serious distraction from the real business of getting to the bottom of that iconic negative image.
I knew you would want to see this.