Yep Jabali agree with everything you said but as OSR is supposedly damage to the barrel caused by a dimensional change (so it seems everyone is inferring or saying as a fact) I was really inferring that a colour or appearance change was not measurable dimensionally or as I put it, in the physical sense although as you then quite rightly put it, even colour changes are in some way measurable.

Gets confusing when using all these terms. I guess what frustrates me a bit in this thread and the previous one on the subject is that nobody has said (to my knowledge) that they can run their finger over the barrel surface and 'feel' OSR. Just like the ubiquitous UFO, it's all just visual until someone grabs hold of one and can say for sure they are real objects.