Dear Alan. Do you think that the stry finish with your post? You are wrong! ? 

Take that vase, and bring him together with the test certificate to one (I will not say the name) of the three major auction houses in London.

Do you know what? They will tell you that the certificate is not valid because they only trust Oxford Authentication, which is idiot.

I am not saying that Oxford Authentication is not reliable, what is idiot is the fact that such aution house only rely on them, without knowing if, as is the case with another test laboratory, there are others equally reliable if not even better.

Who at least release the test results (which Oxford do not do) and are more available to discuss and answer questions.

My experiences with Oxford authentication has been really bad to say the least.

If you pay a lab for your blood tests and all what they will tell you is "you are ok, do not worry", are you happy? Absurd.

Giovanni

Dear Alan,

something strange there, actually. In my previous post I was going to say that I ahve already heard elsewhere that there have been problems with Kotalla, but at the end I didn't say it because it is not right to say something only based on what has been heard.

But then I went at the site of the auction and did read the description made by the Auction house. It sounds odd to say the least, they say that it has been confirmed authentic but they guarantee nothing.

And then, I have seen that the item has ben canceled from the sale!

Something not right there, it seems.

Giovanni

Dear Giovanni,

I promised I would post nothing more today, and now I am breaking my promise!

You are quite right about the total nonsense that only Oxford Authentication is acceptable. If nothing else, this is an insult to other laboratories which are just as competent. It may be that there is some business connection between Oxford Authentication and the auction house you have in mind. And I think I know which one it is!

And now the reason why I have broken my promise. If you are following Rasmussen online now, as I am, you will see that lot 14, the Yuan jar, was withdrawn a few minutes ago! Can it be that the adverse and dismissive opinion of the London dealers has destroyed its credibility, even though an entirely respectable laboratory has confirmed its age by TL testing? If so, this is appalling. 

Mr Rasmussen did announce, however, that if anyone is interested in buying it, they should make contact after the sale. Here is your chance!

Alan

Dear Alan we did post at the same time!

Indeed!

A.

Dear Alan and Giovanni:

Your posts just confirm what most of us already knew or suspected namely that even so-called experts in Chinese porcelains are completely fallible. I think the experts get more assessments correct than most of us do based on a lifetime of experience but they presumably have their own biases. Also, there are few real scientific or objective criteria for dating an  individual piece. There are a lot of subjective assessments that go into every decision. I still get very confused when I hear discussions about how a vase's foot, for example, identifies it as belonging to a certain reign.

Regarding the Oxford Authentication test, I assume that like all tests it is subject to errors? However, thermoluminescent testing is presumably overall a more accurate way of assessing the age of a bronze or porcelain object than simply looking at it?  However, various thermoluminescent tests might differ in accuracy depending on how good the laboratories are.

Regarding your comments on Michael Vermeer, I think it is likely that like every expert he made errors and Christie's might have not agreed with some of his labeling of items in his collection. I did not know Mr. Vermeer or ever correspond with him. However, a USA dealer for whom I have a lot of respect told me that he was an inveterate collector and that he was not above occsionally buying substandard items just because he liked them. So with all due respect to his undoubted expertise some of his items might truly have been substandard or of a later period than the one he subsequently assigned them to.

So Chinese art is a difficult field filled with pitfalls and even the experts might be completely wrong about individual items as you point out.

Regards,

Errol 

Hi Alan and Giovanni you both may recall the former head of Sotheby's Mr Julian Thompson stating prior to his death that the 2 doucai chicken cups held currently at the Beijing palace museum were fakes.

If you go to the major auction today and enquire with x and go back one year later, the odds are that that person no longer works there. It is very odd with the large turnaround of experts who seem to be more concerned with Provence than anything else.

I did not know V himself but I did know Julian.

Mark

Dear Mark,

I was never in touch personally with Julian Thompson, though I rather fancy that by the strange alchemy of associations that we all share, we know people who know people who knew people, and so on and on, world without end. I seem to recollect that Sotheby's sold his study collection of ceramics off, not all that long ago, or am I confusing this? Nor did I know he had said that the Chenghua chicken cups in Beijing were fakes. I wonder how he came to know that?

Best wishes,

Alan

Hi Alan,

I am trying to find said essay. I do know that it was published in a Sotheby's catalogue that was written by Regina Krahl.

If I find said essay I shall post.

Mark

Dear All,

TL testing has it's problems if an object has ever been subject to X ray or buried in soils with a high radiation content. Absolutely not trying to suggest that the item which is the subject of this thread has been  subject to x ray prior to it's test.  As with most scientific testing you need more than one sample to be sure of your results. That may prove difficult with antique porcelain You have to be able to prove that both your samples have had a similar history. If one item has spent time in Chernobyl for instance it would give a false reading. I do not pretend to fully understand the science but apparently there are other tests that need to be done in conjunction with TL testing to filter out anomalies. Perhaps Oxford have a better understanding or more advanced equipment to do these other tests. And that's why they are favored by the major Auction houses.

Regards

Michael   

Dear Mark, Dear Michael,

Mark - please do let me know if you find Julian Thompson's discussion in a past Sotheby's catalogue, I'd certainly be interested to read it, but don't put yourself out, there aren't enough hours in the day most of the time.

Michael - distortion of TL readings by X-ray exposure and any attempt to falsify the glow curve can be detected now by proficient laboratories and taken into account. This means that if an item has been tampered with, while its date may not be derivable, the test would equally never express a view on its age; rather, any attempt at a falsifying radiation exposure is likely to be detectable, and would not result in the expression of the view that the item tested was of such and such a date. (Have a look at Oxford Authentication's website.) In the case of the TL test result obtained on lot 14 of the recent Rasmussen sale, an opinion of a fourteenth century date for it was stated. Such a date would never have been advanced by any lab capable of detecting an exposure to falsifying radiation, and I'm assuming that the lab which did the test on lot 14 ought to be proficient in that regard. A second TL done by an independent lab seems the sensible way forward in this instance. There are other, less invasive tests available, but they are still in relatively early stages of development. X-ray fluorescence is one of them, a promising technique that you can read up on for yourself. Bohams had heralded a partnership with the Cranfield Laboratory a few years ago for the development of XRF testing, but as far as I can tell from talking to some of the Bonhams staff in Bond Street, the initiative appears to have gone quiet of late.

Regards,

Alan

Thanks Alan,

I did visit the Oxford site a month or so ago, i had read a news story that referenced them. I noticed then that Oxford stated they had recently changed one of their methodologies to slicing the core sample rather than crushing it. Apparently due to the hardness and crystalline structure of porcelain the heat generated in the crushing distorted the test results. The point I was trying to make perhaps poorly is that maybe it is the method of testing that is in question and rather than some dark conspiracy against the object, it's owners or the auction house. I seem to recall when I visited the Oxford site quite a few of the photographic examples of discovered fakes gave grateful acknowledgement to the auctioneer involved in this sale so assume they have had a good relationship.  

Regards

Michael           

Thanks Alan,

I did visit the Oxford site a month or so ago, i had read a news story that referenced them. I noticed then that Oxford stated they had recently changed one of their methodologies to slicing the core sample rather than crushing it. Apparently due to the hardness and crystalline structure of porcelain the heat generated in the crushing distorted the test results. The point I was trying to make perhaps poorly is that maybe it is the method of testing that is in question and rather than some dark conspiracy against the object, it's owners or the auction house. I seem to recall when I visited the Oxford site quite a few of the photographic examples of discovered fakes gave grateful acknowledgement to the auctioneer involved in this sale so assume they have had a good relationship.  

Regards

Michael           

Thanks Alan,

I did visit the Oxford site a month or so ago, i had read a news story that referenced them. I noticed then that Oxford stated they had recently changed one of their methodologies to slicing the core sample rather than crushing it. Apparently due to the hardness and crystalline structure of porcelain the heat generated in the crushing distorted the test results. The point I was trying to make perhaps poorly is that maybe it is the method of testing that is in question and rather than some dark conspiracy against the object, it's owners or the auction house. I seem to recall when I visited the Oxford site quite a few of the photographic examples of discovered fakes gave grateful acknowledgement to the auctioneer involved in this sale so assume they have had a good relationship.  

Regards

Michael           

Thanks Alan,

I did visit the Oxford site a month or so ago, i had read a news story that referenced them. I noticed then that Oxford stated they had recently changed one of their methodologies to slicing the core sample rather than crushing it. Apparently due to the hardness and crystalline structure of porcelain the heat generated in the crushing distorted the test results. The point I was trying to make perhaps poorly is that maybe it is the method of testing that is in question and rather than some dark conspiracy against the object, it's owners or the auction house. I seem to recall when I visited the Oxford site quite a few of the photographic examples of discovered fakes gave grateful acknowledgement to the auctioneer involved in this sale so assume they have had a good relationship.  

Regards

Michael